Nghiên cứu đặc điểm dịch tễ học lâm sàng và đánh giá kết quả can thiệp điều trị bệnh phổi tắc nghẽn mạn tính tại tỉnh nghệ an tt tiếng anh

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BACKGROUND
1. Rationale
Chronic obstructive pulmonary disease (COPD) is a common
respiratory disease worldwide as well as in Vietnam, the incidence and
mortality rate increasing with high burdens of treatment costs and
causing severe disability. According to the World Health Organization,
COPD is the third leading cause of death (after ischemic heart disease
and stroke). COPD is also one of the 10 incurable diseases worldwide.
There are estimated 329 million people with COPD worldwide and this
number will continue to increase in the coming decades due to increased
exposure to COPD risk factors and aging of the population. Although the
disease is preventable and treatable, diagnostic and treatment guidelines
for stable COPD and exacerbations are frequently updated, but
implementation is still challenging, especially in the community and
primary care settings. It’s the fact in Vietnam that not many patients with
COPD are properly diagnosed, managed and treated in accordance with
the MOH's guidelines at the primary care level, the main reasons are
unfavorable geographical, economic and social conditions of the patients,
others factors included the limitation of healthcare facilities, equipment,
qualifications of health workers and health insurance payment at primary
care levels. Therefore, intervention in health education and
communication to raise awareness for people, patients and health
workers about COPD is an immediate and long-term task to coordinate
the detection, treatment and prevention of this dangerous disease.
2. Scientific meaning and practicality of the dissertation
- Determined the prevalence of COPD in Nghe An, estimate the
number of people with COPD in the community, thereby establishing a
screening plan and effective COPD management office in the
community.
- Assess the main risk factors of the disease, determine which risk

factors can be prevented, then propose effective prevention methods to
reducing the incidence of COPD in the future.
- Analyze the clinical characteristics, ventilation function and
electrocardiogram findings in COPD patients, then suggest screening
people with high risk factors for COPD.
- Assess the treatment counseling methods at the community level,
contributing to reducing the economic burden on the family and society.
On the other hand, raise awareness for patients about adherence to
treatment, re-examination to reduce exacerbation and hospitalization.


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3. Research objectives
i. To determine the prevalence and main risk factors for chronic
obstructive pulmonary disease in people aged 40 and over in Nghe
An province, the period of 2017-2019.
ii. To describe the clinical characteristics, ventilation function and
ECG findings among subjects with chronic obstructive pulmonary
disease.
iii. To measure the results of therapeutic interventions for chronic
obstructive pulmonary disease in the community.
4. Structure of the dissertation
- The dissertation consists of 135 pages (not including the references
and appendices). The dissertation consists of 7 parts: Introduction: 2
pages, Chapter 1. Overview: 32 pages, Chapter 2. Subjects and research
methods: 25 pages, Chapter 3. Research results 36 pages, Chapter 4.
Discussion: 37 pages, Conclusion: 2 pages, Recommendations: 1 page.
- The dissertation consists of 33 tables (the results section 31 tables),
17 charts and 6 figures, 212 references including 14 articles in
Vietnamese, 198 articles in English. The appendix includes research

sample, list of enrolled patients, list of intervention-control patients,
intervention forms ...
CHAPTER 1: LITERATURE REVIEW
1.1. Epidemiology of COPD
Epidemiology of COPD worldwide
WHO report shows that, in 2017, there were 56.9 million deaths
worldwide, of which 54% died from 10 common causes and COPD was
the 3rd leading cause of death. According to WHO forecasts, by 2020,
COPD will be the third leading cause of death after coronary and
cerebrovascular disease. Data from studies show that the COPD mortality
rate in 2000 was 2.95 million, ranking the fourth leading cause of death.
Smoking is the second leading risk factor for death with 7.1 million
cases, and this is also a major risk factor for COPD. Thus, it is predicted
that the mortality rate due to COPD will increase, while infectious
diseases will tend to decrease.
Epidemiology of COPD in Vietnam
An epidemiological study of Ngo Quy Chau et al. (2006) in Hanoi
showed that the prevalence of COPD for both genders was 4.7% of the
population over 40 years old, of which male 7.1% and female 2.5%. A
recent study by Phan Thu Phuong (2010) on the prevalence of COPD in
suburban Hanoi and Bac Giang province, the prevalence of COPD among


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people over 40 years old was 3.6%, of which male 6.5% and female 1.2%.
According to Dinh Ngoc Sy et al, in a national COPD epidemiological
survey in 2006, the prevalence of COPD among the population aged 40
and over was 4.2%, male 7.1%, female 1.9%, rural areas 4.7%, urban
3.3%, mountainous 3.6%, North 5.7%, Central 4.6%, South 1.9%.
1.2. Risk factors of COPD

Smoke: Statistical studies have confirmed that smoking is the
leading cause of COPD. According to ATS, approximately 15-20% of
smokers have COPD and 80-90% of COPD patients are addicted to
smoking.
Environmental pollution and indoor pollution: Doiron D et al
(2019) studying the effect of air pollution on lung function in the UK
showed that an increase in the concentration of PM 10 and PM2.5 in air has
related to the decline in FEV1 (-83.13 mL) and FVC (-73.75 mL), on the
other hand, the prevalence of COPD is also higher in areas where the
concentrations of PM2.5 and PM10 are above 5 µg/m3. Indoor air pollution
also affects lung function and COPD. In developing countries, using
natural gas in cooking or firewood, straw, coal... accounts for 50%,
which pollutes the living environment.
Exposure to occupational smoke and dust: Occupational
environmental factors play an important role in respiratory disease. The
risk of COPD related to occupational factors was first widely publicized
and accepted in the study results of Schilling et al. in the 1960s.
Subsequent studies have shown that COPD and occupational factors are
closely related.
Infections: The development of respiratory tract disease in adults is
related to a history of childhood respiratory disorders, the impact of
pneumonia in young children, and COPD is not well defined.
Climate: There is a link between COPD exacerbations and climate
(especially temperature and humidity). It is possible that the high
humidity associated with air infections or dry air in cold weather causes
the appearance and aggravation of respiratory symptoms, and the number
of COPD exacerbates hospitalized also increases during cold weather.
Genetic factors: Deficiency of α1 - antitrypsin is a known risk
factor of genes for COPD. Deficiency of α1 - antitrypsin increases the
risk of COPD by 30 times. However, this protein deficiency only

accounts for less than 1% of cases of COPD.
Asthma and airway hyper-reactivity: Asthma and airway hyperresponsiveness have also been identified as risk factors for COPD.


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Age and sex: In most epidemiological studies on COPD, the
prevalence, disability level, and death rate increase with age. The
increased prevalence of COPD in recent years is due to an aging world
population and a lower death rate due to cardiovascular diseases and
acute infections.
1.3. Pathogenesis of COPD
The pathogenesis of COPD is very complex, so far a number of
theories have been mentioned.
- Inflammatory reaction of the respiratory tract.
- The imbalance of proteinase and anti-proteinase system.
- The attack of free oxygen radicals.
1.4. Clinical manifestations, evaluation and diagnosis of COPD
Clinical manifestations: A chronic cough is often the first
symptom of the disease; Chronic sputum production is common in 50%
of smokers. Dyspnea on exertion, progressively worsening over time,
chest tightness, shortness of breath, or panting are symptoms that can
make a patient worried. Chest pain is a common symptom but tests that
look for the cause of chest pain in patients often give a negative result.
Evaluation: Spirometry is the gold standard for definitive
diagnosis, especially early diagnosis, determination of severity, and
monitoring of disease progression. Airflow limitation that is irreversible
or only partially reversible with bronchodilator is the characteristic
physiologic feature of COPD: post-bronchodilator Gaensler index
(FEV1/FVC) <70%. Lung x-rays are useful for differential diagnosis.
Electrocardiogram has prognostic significance as well as assessment of

concurrent cardiovascular disease.
The diagnosis of COPD is confirmed by the following:
- Confirmed diagnosis of COPD: when Gaensler index after
bronchodilator test (FEV1 / FVC) < 70%.
- Diagnosis disease severity base on to respiratory function and clinical
manifestations.
1.5. Methods of epidemiological research
In medical science, there are two basic types of research methods:
descriptive and analytical research.
Cross-sectional research is now widely used as an analytical study
to test causal hypotheses between exposure and disease, based on
findings from cross-sectional studies and the support of other available
evidence. The advantage of cross-sectional research is that it is easy to


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implement, inexpensive, but the disadvantage is that it is not possible to
determine the chronological order between cause (exposure factor) and
consequence (disease), because both of these factors are recorded at the
same time.
Intervention research: this type of research has great practical
value in medical research. The research design must be meticulously
rigorous, conducting research in according to the proposal, ethical issues
need to be considered and addressed. Selection of control group must
consider about the living environment and physical condition of the study
subjects. Consider the measure to be implemented, ability of the study
subjects to comply with the study measures or medication used.
1.6. The role of Communication for Health Education
Communication for Health Education has 3 important tasks:
improving people's knowledge about health; change people's attitudes

about health; people's practice of health.
There are two methods to conduct communication for health
education activities: direct and indirect.
1.7. Management of COPD in the community
Outpatient treatment of COPD at a stable stage to avoid
exacerbation is a highly effective solution. The direct cost of maintaining
therapy for a patient with COPD in a stable period per year is only about
VND 20 million compared to more than VND 200 million which is the
cost to pay for patients who have to be admitted to the hospital for
exacerbations. This means that we can help reduce costs by 90% if we
treat patients with COPD at a stable stage. Therefore, to reduce the
burden of COPD exacerbation, the most economical solution is to build a
standard COPD Outpatient Management Unit at the district level.
1.8. Research on treatment adherence of patients with COPD
Treatment adherence is a concept that indicates to which extent a
patient's behavior corresponds with the agreed recommendations from a health
care provider, including medication use, dietary and/or lifestyle changes.
There are many factors associated with treatment adherence,
including age, gender, education, ethnic, smoking status, amount of
medication taken per day, stage of the disease or cost of treatment.
Different methods of adherence assessment will bring different results.
Currently there are 2 ways to assess treatment adherence: subjective and
objective measure.


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CHAPTER 2
SUBJECTS AND METHODS OF RESEARCH
2.1. Scope, place and time of research
The research was conducted on 4,000 subjects aged 40 and over,

distributed over 4 regions of Nghe An province during the period of
January 2017 to February 2019.
2.1.1. Research subjects
Criteria for selecting research subjects
- People aged 40 and above follow the selected sample size.
- People with COPD in the intervention research group: physically and
mentally healthy enough, have adequate time to participate in the study.
- COPD diagnostic criteria: Airflow limitation that is irreversible or
only partially reversible with bronchodilator: FEV1/FVC <0.7 after
bronchodilator test (FEV1 increase <200ml and increase <12% after
bronchodilator test).
Exclusion criteria
- Subjects with: mental disorders, non-cooperating, incapable to
answer the questionnaire.
- Subjects suffer from diseases that hinder measurement and affect
the results of spirometry.
- Subjects did not agree to participate in the study.
2.1.2. Research sites
The study was conducted in 4 districts: Tuong Duong, Tan Ky, Dien
Chau and Quynh Luu.
Sites for Clinical epidemiological research: at 20 commune health
stations in 4 studied districts.
Sites of intervention for COPD patients: at 4 district health centers
and 20 commune health stations.
2.1.3. Research period: From January 2017 to February 2019
2.2. Research Methods
2.2.1. Research design:
Cross-sectional descriptive epidemiological study with analysis:
+ Determining the prevalence of COPD in people aged 40 and older
in Nghe An.

+ Analyzing risk factors of disease
+ Assessing clinical symptoms, analyzing ventilation functions and
ECG strips of patients with COPD.
Controlled therapeutic counseling research:


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+ Conducting therapeutic counseling intervention with club
activities of patients with COPD within 1 year.
+ Cross-sectional survey to evaluate the effectiveness after 1 year of
intervention.
2.2.2. Research Sample Size
- Formula for calculating cross-section epidemiological study sample size
𝑝(1−𝑝)
2
n =𝑍1−𝛼/2
x DE
𝑑2
Of which:
 𝑍1−𝛼/2 (Reliability coefficients) = 1,96 (standard percentile scale
at statistical significance level α = 0.05)
 p = 0,05 (Estimated prevalence of COPD, take p = 5% according
to previous studies in Vietnam)
 d: confidence level (desired accuracy), choose d = 0.01
 DE = 2 (Design Effect)
Sample size calculated: n = 3650 people
Adding 10% to eliminate errors of cases of absence or noncooperation in the survey, the actual number of subjects needed for the
study is n = 4000 people.
- Formula to calculate intervention study sample size:
2

n = 𝑍(𝛼,𝛽)

𝑝1(1−𝑝1)+𝑝2(1−𝑝2)
(𝑝1−𝑝2)2

p1: estimated rate of practice using a bronchodilator dispensing
device before intervention is 5%.
p2: The rate of practice using the bronchodilator dispensing device
after intervention expected to reach 25%.
2
𝑍(𝛼,𝛽)
= 10,5 (Look in table Z with α = 0.05, β = 0.1)
Sample size calculated: n = 62
In fact, we selected entire 166 COPD patients through
epidemiological studies, divided into 2 groups: 83 patients in the
intervention group and 83 patients in the control group.
2.2.3. Research variables and indicators
- Variables of general information of research subjects: age, age
group, gender, education, height, weight, blood pressure.
- Variables and indicators of clinical epidemiological research:
history of disease, exacerbation, hospitalization, exposure to risk factors,
symptoms.


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- Variables and indicators of clinical and laboratory examination:
clinical examination, ECG results, ventilation function.
- Variables and indicators of intervention research: time of study,
time after intervention, symptoms, number of exacerbations, number of
hospital admissions, number of follow-up visits, adherence to treatment,

amount of medication used, steps to use drugs ...
2.3. Planning and implementing research
- Staff training
- Prepare for questionnaires
- Research facilities: spirometer, ECG Machine, stethoscope,
sphygmomanometer...
- Implementing research:
+ Information gathering technique
+ Clinical examination
+ Ventilation functions measurement and results analysis
+ ECG measurement and results analysis
- Intervention research and results assessment:
+ Object, time, place of intervention
+ Implementation steps
+ Content of implementation
+ Assessing the results of intervention
2.4. Research bias and errors
2.5. Data processing methods
The data collected were imported and processed with medical
statistical algorithms using the computer software program STATA
version 13.0.
2.6. Research ethics
+ Research was approved by the Proposal Approval Council and
the Medical Ethics Council of Hanoi Medical University.
+ Research was approved by local authorities and local healthcare
facilities.
+ People and patients of 4 studied districts were consulted and
voluntarily agreed to participate in the study.
+ People who have been diagnosed with COPD for the first time
are advised to have examination, treatment and prevention of diseases in

accordance with regulations.
+ Research results are reported back to patients


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CHAPTER 3: RESULTS
During the study period, we screened 4,000 people who met the
cross-sectional epidemiological research criteria, and identified 166
patients with COPD according to GOLD and MOH’s standards.
3.1. Prevalence and risk factors for COPD in people aged 40 and older
3.1.1. Prevalence of COPD
We combine clinical examination, pulmonary ventilation function
measurement and bronchodilator test to determine disease. The study has
identified 166 people with COPD among 4,000 people aged ≥ 40
screened, accounting for 4.15%. The proportion of patients diagnosed
with COPD for the first time is 93.34%.
Table 3.8. Prevalence of COPD by districts, gender
Gender
District
Dien
Chau
Quynh
Luu
Tan Ky
Tuong
Duong
In
General

COPD
Non
COPD
COPD
Non
COPD
COPD
Non
COPD
COPD
Non
COPD
COPD
Non
COPD

Male

Female

Total

(n=1671)

%

(n=2329)

%

(n=4000)

%

40

10,10

9

1,55

49

5,02

356

89,90

572

98,45

928

94,98

37

8,49

6

1,02

43

4,21

399

91,51

580

98,98

979

95,79

31

7,77

4

0,69

35

3,56

368

92,23

579

99,31

947

96,44

33

7,50

6

1,04

39

3,83

407

92,50

573

98,96

980

96,17

141

8,44

25

1,07

166

4,15

1530

91,56

2304

98,93

3834

95,85

Dien Chau has 49/977 research subjects diagnosed with COPD,
that’s the highest prevalence of COPD among studied districts (5.02%),
meanwhile the prevalence of COPD detected in Quynh Luu was 4.21%,
Tuong Duong 3.83% and the lowest prevalence is in Tan Ky (3.56%).
The prevalence of COPD is highest in the age group ≥ 60 years,
accounting for 83.73%. Among them, the age group of 60-69 accounts
for 35.54% and age group ≥70 years makes up 48.19%. Prevalence in
males was 8.44% and female was 1.07%.


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The average age of the subjects with COPD was 68.81 ± 10.06,
higher than the average age of the group without COPD (60.44 ± 11.18),
with p <0.001.
3.1.2. The Association between Risk Factors and COPD
Table 3.18. Multivariate logistic regression analysis of risk factors
for COPD
Related factors
Smoking
Non-smoking
Smoking <15 pack-years
Smoking 15-30 pack-years
Smoking ≥ 30 pack-years
Kitchen smoke exposure ≥30 years
Occupational dust exposure ≥ 20 years
History of respiratory disease

Age subgroup
40-49
50-59
60-69
≥70
Gender (male)
BMI <18.5 (underweight)

COPD Subjects
(166) (3834)

%

OR

95%CI

35
33
63
35
160
16
36

2803
496
366
169
3178

35
185

1,23
6,24
14,69
17,16
4,79
45,71
19,46

1
5,33 3,3-8,6
13,8 9,0-21,1
16,6 10,1-27,2
3,7
1,6-8,7
16,3 7,0-38,1
2,7
1,6-4,3

8
19
59
80
141
49

749
1118

1235
898
1671
500

1,07
1,7
4,78
8,91
8,44
9,8

1
1,6
4,6
9,1
3,2
0,4

0,7-3,7
2,2-9,8
4,3-18,9
1,9-5,6
0,3-0,6

+ Variables have significant association with COPD were smoking,
kitchen smoke exposure ≥ 30 years, occupational dust exposure ≥ 20
years, history of respiratory disease, age and gender:
+ Smokers with ≥ 30 pack-years are 16.6 times more likely to have
COPD than non-smokers, while smokers with 15-30 pack-years and with

< 15 pack-years are at 13.8 times and 5.33 times higher risk of COPD
compared to non-smokers, respectively.
+ Exposure to cooking fumes ≥ 30 years, exposure to occupational
dust for ≥ 20 years is at risk of COPD 3.7 and 16.3 times higher than
those who have no contact or less exposure, respectively.
+ People with a history of respiratory disease are at 2.7 times higher risk
for COPD, men are at 3.2 times higher risk of COPD than women.


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+ The risk of COPD increases with age, people aged 70 and over
are 9.1 times more likely to have COPD compared to people aged 40-49.

Chart 3.2. Risk factors to COPD
3.2. Clinical and laboratory characteristics of subjects with COPD
The clinical symptoms of COPD subjects such as cough, sputum
production and dyspnea account for a high proportion (62.65%, 52.41%
and 45.78%). The asymptomatic group accounted for 15.06%.
Subjects with COPD most often encountered in subgroup A
accounted for 45.22%, subgroup B accounted for 37.35%. C and D
subgroups account for less than 5%.
004%

037%

Subgroup A (n=90)
Subgroup B (n=62)
Subgroup C (n=6)
Subgroup D (n=8)

005%

054%

Chart 3.4. Classify COPD according to GOLD 2019 (n = 166)
Subjects with COPD had hypertension accounted for 26.51%
(systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥
90mmHg). Lung examination with decreased breath sounds and
increased resonance to percussion accounted for respectively 60.84% and


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54.22%. Wheezes, crackles at the lung bases accounting for 25.9%,
tachypnea with > 20 times/minute accounts for 13.25%.
Ventilation function of the COPD group has decreased, manifested in
obstructive ventilatory disorder with average FEV1/FVC ratio was 54.8% ±
10 after bronchodilator test, FEV1% was 70.4 (% of theoretical value).
The indicators of small airway obstruction are also significantly
reduced. Comparing the measured results of ventilation function of the
COPD subjects after bronchodilator test, the indicators increased very
little or not. Subjects with COPD encountered the most in the GOLD 2
stage accounting for 45.78%, followed by GOLD 1 accounting for
32.53%. GOLD 4 stage only accounted for 3.01%.
GOLD 1 (n=54)
GOLD 2 (n=76)
GOLD 3 (n=31)
GOLD 4 (n=5)

046%
019%

033%

003%

Chart 3.5. Classification of airflow limitation severty in COPD based
on post-bronchodilator FEV1 (n = 166)
100%

096% 100%

80%

070%

067%

055%

60%

054%

40%

032%

031%

029%

029%

027%

033%

031%

025%

20%
0%
FVC (% of
predicted)

FEV1 (% of
predicted)

FEV1/FVC
(%)

MMEF (% of
predicted)

Pre-test

FEF75 (% of
predicted)

FEF50 (% of
predicted)

FEF25 (% of
predicted)

Post-Test

Chart 3.6. Spirometry results of subjects with COPD (n = 166)


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The most common arrhythmias on ECGs are sinus tachycardia
accounting for 19.28%, right bundle branch block accounts for 4.22%,
atrioventricular block accounts for 1.2%, atrial fibrillation accounts for 3.61%.
The most common atrial and ventricular abnormalities found on ECGs were
the right atrial enlargement accounts for 20.48%, right ventricular
enlargement accounts for 2.41% and left ventricle enlargement accounts for
1.81%. There are 2 patients with anterior wall myocardial ischemia
accounting for 1.2%. There are differences of abnormal ECG findings
between GOLD1-2 and GOLD3-4 COPD patients. Groups with severe and
very severe obstruction are 2.77 times more likely to have ECG abnormal
findings compared to the mild and moderate obstruction group, with
p<0.01.
Table 3.24. Electrocardiographic changes of the study subjects

Heart rate

Atrial/ventricula
r enlargement

Other changes

ECG findings
Sinus rhythm
Sinus tachycardia
Atrial fibrillation
Premature atrial complexes
AV Blocks
Right bundle branch block
Right atrial enlargement
Right ventricular
enlargement
Left ventricular enlargement
Myocardial ischemia

n
118
32
6
1
2
7
34

Percentile (%)
71,08
19,28
3,61
0,6
1,2

4,22
20,48

4

2,41

3
2

1,81
1,2

Table 3.25. Association between COPD and abnormal ECG findings
GOLD
GOLD 1-2
GOLD 3-4
OR
p
ECG
(95%CI)
n
%
n
%
Normal
83
50
14
8,43

2,77
Abnormal
47
28,31
22
13,26
<0,01
(1,27-6,05)
Total
130
78,31
36
21,69
3.3. Results of intervention after 12 months
The longitudinal follow-up of intervention and control groups after
12 months showed that the study completion rate accounted for 78.3%
(130/166), the is no difference in the number of subjects dropping out of
the study between the 2 groups, with p > 0.05.
At the time prior to the intervention, there is no different in the rate
of subjects currently smoking between the two groups, p> 0.05. After the
intervention, the smoking cessation rate in the intervention group


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decreased from 16.67% to 3.03%. Meanwhile, the control group
decreased slightly, from 15.6% to 14.1%. Smoking rates decreased in 2
groups has statistical significance with p <0.001.

20%

17%

16%
14%

15%
Before intervention
(p>0.05)

10%

After intervention
(p<0.001)

03%

5%
0%
Intervention
group (n=66)

Control group
(n=64)

Chart 3.8. Smoking rates before and after the intervention of the
study subjects (n = 130)
The percentage of subjects with cough symptoms in the intervention
group decreased from 60.6% to 51.5%, p <0.01. In the control group, it
decreased from 64.0% to 53.1%, p <0.01. The different in reduction rate
between 2 groups is not statistically significant, p> 0.05. The percentage

of subjects with symptoms of sputum production decreased from 47.0%
to 45.4%, p<0.01, while in the control group, it decreased from 53.1% to
39.0%, p<0.01. The different in reduction rate between the 2 groups is
not statistically significant, p> 0.05.


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20%

25%
20%

17%
14%

15%

Before Intervention
(p>0.05)
After Intervention
(p>0.05)

09%

10%
5%
0%
Intervention
Group (n=66)

Control Group
(n=64)

Chart 3.11. Rate of exacerbations before and after the intervention of the
study subjects (n = 130)

16%
14%
12%
10%
8%
6%
4%
2%
0%

14%

14%

13%

03%

Before Intervention
(p>0.05)
After Intervention
(p<0.05)

Intervention Control Group
Group (n=66)
(n=64)

Chart 3.12. Rate of hospitalization for acute exacerbations of COPD
before and after intervention of study subjects (n = 130)
Mean acute exacerbations rate in the intervention group decreased
from 0.18 ± 0.52 to 0.1 ± 0.36 after 12 months with p <0.05, meanwhile
the control group decreased from 0.31 ± 0.75 to 0.26 ± 0.57, p> 0.05.
Mean acute exacerbations rate in the intervention group decreased
compared to the control group after 12 months, p <0.05. Hospital
admissions of acute exacerbations in the intervention group decreased from
0.17 ± 0.48 to 0.03 ± 0.17 with p <0.01, the control group was 0.17 ± 0.45 to
0.14 ± 0.39 after 12 months, p> 0.05. Difference in the mean acute


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exacerbations and hospitalization rates between control group and
intervention group after 12 months are statistically significance with p <0.05.
Table 3.26. Mean exacerbations and hospitalizations rates of study
subjects (n = 130)
Subgroups
Mean/year

Intervention group
(n=66)
Before
After (2)
P
(1)

(1)-(2)
̅
̅
𝑋 ±SD
𝑋 ±SD

Control group
(n=64)
Before
After
P
(3)
(4)
(3)-(4)
̅
̅
𝑋 ±SD
𝑋 ±SD

Mean acute
exacerbations 0,18±0,52 0,10±0,36 <0,05 0,31±0,75 0,26±0,57
rate
Mean hospital
admission 0,17±0,48 0,03±0,17 <0,01 0,17±0,45 0,14±0,39
rate

P
(1)-(3)*
(2)-(4)**

>0,05

>0,05*
<0,05**

>0,05

>0,05*
<0,05**

Before intervention, the rate of hospitalization for acute exacerbations
in the intervention group accounted for 13.64%, the control group 14.06%,
p> 0.05. After 12 months, the hospitalization rate for acute exacerbations of
intervention group decreased from 13.6% to 3.03%, the control group
decreased from 14.1% to 12.5%. There are differences between the 2 groups
with p <0.05.
Before intervention, the rate of the use of pressurized metered-dose
inhaler (pMDI) was low in both groups. After 12 months, the number of
people using pMDI in the intervention group increased from 6.06% to
40.91%, and the control group increased from 10.94% to 12.5%. There is
a difference in using pMDI between 2 groups after 12 months, with p
<0.001. The rate of using Turbuhaler in the intervention group after 12
months increased from 3.03% to 27.27%, the control group increased
from 6.25% to 10.94%. There is a difference in the rate of increase of
Turbuhaler use in the intervention group compared to the control group,
with p <0.05.
At the time of study, the intervention group had 4 subjects using
pMDI, the control group had 7 subjects, none of them completed all 6
steps correctly. After 12 months, the intervention group had 27 subjects
using pMDI, the rate of correct implementation of all 6/6 steps accounted

for 44.44%; The control group had 8 subjects but none of them
performed 6/6 steps correctly. There is a difference in the rate of
preforming correct steps between the two groups with p <0.001.
The intervention group had 2 subjects and the control group had 4
subjects using Turbuhaler before the intervention, none of the subjects
performed all 4 steps correctly. After 12 months, the intervention group


17
had 18 subjects using pMDI, the correct implementation of 4/4 steps
accounted for 61.11%; the control group had 1 subject performed 4/4
steps correctly, accounting for 14.28%. There is difference in the rate of
performing all correct steps between two groups with p <0.001.
The re-visit rate after 12 months reached ≥ 80% of scheduled
visits/year (over 10 visits/12 months) in the intervention group,
accounted for 24.24%, while in the control group was 9.38%, p <0.05.
Table 3.30. Precentage of Morisky adherence scale (n=130)
Group
Adherence Scale
High adherence
(Score = 8)
Medium Adherence
(6 ≤ score < 8)
Low Adherence
(Score < 6)
Mean score (𝑋̅±SD)

Intervention Group
(n=66)
n

%

Control group
(n=64)
n
%

21

31,82

6

9,38

25

37,88

13

20,31

20

30,30

45

70,31

6,0 ± 1,59

4,8 ± 131

p

<0,0001

<0,001

Morisky adherence scale of the intervention group in the order of high
adherence, medium adherence and poor adherence respectively 31.82%,
37.88% and 30.30%. Meanwhile, the control group with low adherence
accounted for 70.31%, good adherence accounted for 9.38%, there is
difference between two groups with p <0.0001. The average Morisky score
was higher in the intervention group than in the control group, p <0.001.
CHAPTER 4: DISCUSSION
4.1. Prevalence and risk factors for COPD
4.1.1. Methods
Epidemiological studies of COPD are usually conducted with crosssectional study, prevalence is usually calculated based on the study of a
group of subjects representing the general population. In the past, COPD
epidemiological studies around the world have relied on a variety of
diagnostic approaches, possibly based on the physician's clinical
diagnosis, patient's questionnaire set, spirometry or combined above
aspects. The inconsistency in diagnostic approach and assessment of
airway obstruction leads to differences in the prevalence of COPD
among studies. Nowadays, based on the standard of GOLD that diagnosis
by measuring ventilation functions with FEV1/FVC ratio <0.7 postbronchodilator test as the gold standard for definite diagnosis of COPD.
4.1.2. Prevalence and risk factors associated with COPD

Prevalence of COPD


18
Our study showed that out of 4,000 participants, 166 cases of COPD
were detected, accounting for 4.15%, of which male accounted for 8.44%
and female 1.07%. Among studied districts: COPD prevalence in the
plains (Dien Chau, 5.02%) and coastal (Quynh Luu, 4.21%) is higher
than in mountainous areas (Tan Ky, 3.56%), high mountainous areas
(Tuong Duong, 3.83%). Looking at this difference, we found that the
plains and coastal areas have a high proportion of people smoking; The
average number of pack-years of smoking in Dien Chau and Quynh Luu
was 21.8 ± 11.8 and 19.5 ± 11.47. Whereas in mountainous and high
mountainous areas, people often have a habit of smoking waterpipe
tobacco, the average number pack-years of smoking is lower (Tan Ky
16.7 ± 11.38, Tuong Duong 15.9 ± 11.29). Therefore, it is possible to
cause disparities in the prevalence of COPD due to different smoking
levels in different regions.
The influence of risk factors
Age and COPD
Our study detected 166 COPD patients with an average age of 68.80
± 10.06, the lowest age was 40 and the highest was 91. The prevalence of
COPD tends to increase with age, in male higher than in female. The
lowest prevalence in the age group 40-49 accounts for 4.82%, in the age
group 50-59 is 11.45%, the age group over 60 is 35.54% and the highest
proportion belong to the age group over 70 with 48.19%. Using
multivariate regression analysis of COPD-related factors, we also found
that when compared to the age group of 40-49, the risk of COPD of age
group 50-59 increased 1.6 times, age group 60-69 increased by 4.6 times
and age group 70 and older was 9.1 times more likely to develop COPD.

The higher the age, the higher the risk of developing COPD.
The results in our study are consistent with the study of Phan Thu
Phuong (2010), in which the multivariate logistic model of the age group
50-59 the risk is 4.9 times higher and the age group over 60 is 13 times
higher than the age group 40-49.
Seok Jeong Lee et al (2015) studied non-smoker subjects aged 40
and older in Korea found that men were 4.2 times more likely to develop
COPD than women. Compared to the age group of 40-49, the age group of
60-69 is 3.8 times, the age group of 70-79 is 9.2 times and the age group 80
and older is 17,7 times more like to develop COPD, respectively.
Gender and COPD
In the group with COPD, men accounted for 84.9%, and women
15.1%. The prevalence of COPD in men aged 40 and older in the
community was 8.44% and women 1.7%. Analyzing two variables
(COPD and gender), we found a significant difference in the prevalence


19
of COPD between men and women. However, we found that one of the
confounding factors is the smoking status, the smoking habit among
Vietnamese women in general and rural areas in particular has a
significant difference, in which women were mostly passive smokers.
However, in analyzing the multivariate logistic model, we still found a
difference in the prevalence of COPD by gender, men are 3.2 times
higher risk of COPD (1.9-5.6) than women. Comparing the local studies,
all of the studies show that the prevalence of COPD is higher in men than
women, the rural areas is higher than in urban areas.
Effects of smoking on COPD
Out of our 4,000 study subjects, there were 1161 smokers,
accounting for 29.02%. Of which smokers, 1131/1671 were male

accounting for 69.5%, and only 30/2329 was female, accounting for
1.29%. The percentage of smokers among subjects with COPD is
131/166, accounting for 78.92% and smokers have 10.2 times higher risk
of COPD than non-smokers. The prevalence of COPD tends to increase
with the level of smoking, smokers <15 pack-years with COPD account
for 6.24%, increased by 5.33 times than non-smokers, while smokers 1530 pack-years was 13.78 times more likely to develop COPD and 16.59
times higher among smokers over 30 pack-years compared with those
non-smokers. Studies nationwide and around the world demonstrated that
smoking is closely related to COPD.
Effects of kitchen fumes, occupational dust and a history of
respiratory disease with COPD
Our study results showed that the proportion of people exposed to
kitchen fumes ≥ 30 years accounted for 83.45%, the time of exposure of
subjects live in the mountains area is higher than those live in the plains
and coastal areas, p <0.05. Analyzing with Univariate regression found
that people exposed to kitchen fumes ≥ 30 years were at higher risk of
COPD 5.5 (95%CI, OR 2.42-12.52) times, with multiple regression
analysis we also found that exposure to kitchen fumes ≥ 30 years at
higher risk of COPD 3.7 times (95%CI, OR 1.6-8.7). This result is
similar to Phan Thu Phuong (2010), in which those who were exposed to
kitchen fumes for ≥ 30 years were 3.7 times more likely to have COPD than
those who were not exposed or exposed for less than 30 years. However, in
multivariate regression analysis, the risk factor of kitchen fumes exposure
≥ 30 years gives OR = 1.1 (95% CI, 0.3-3); This may be due to in our
study, the proportion of people exposed to kitchen fumes ≥ 30 years is
higher than the study of Phan Thu Phuong (83.45% compared to 62.3%).
Occupational risk factors in our study also account for a low
proportion, subjects are mainly farmer, some people living in coastal

20
plains are engaged in fishing and salt making. In total, there are 45
people in contact with risk factors suffering from COPD such as mine
workers, cement factory workers, carpenters ... accounting for 1.13%, of
which the study subjects have time to be exposed to occupational dust ≥
20 years accounting for 0.88%. Univariate regression analysis showed
that occupational exposure ≥ 20 years’ group was 21.4 times higher risk
to developing COPD than non-exposed or less than 20 years’ exposure
group; We continued to analyze using multivariate regression, the results
also showed that the risk of developing COPD was 16.3 times higher in
the exposed group ≥ 20 years.
A history of respiratory disease is also one of the risk factors for
COPD after a period of illness. In our study, there were 185 subjects with
a history of respiratory disease, of which 36 subjects had irreversible
obstructive ventilatory disorder, accounting for 19.46%, common
diseases were bronchitis, pneumonia, asthma, pulmonary tuberculosis,
diagnosed at the district or commune healthcare level where spirometer is
not available. Thus, these 36 patients may have COPD but have not been
confirmed, this is one of the limitations to the identification of risk
factors for history of disease in the community.
4.2. Clinical characteristics, ventilation function and ECG findings of
COPD subjects
4.2.1. Clinical characteristics of subjects with COPD
In the analysis of COPD patients, we found that 62.65% of patients
had cough symptoms, 52.41% of patients with sputum production,
dyspnea seen in 45.78% patients, the group of asymptomatic patients
accounted for 15.06%. The extent of dyspnea of COPD patients is graded
based on mMRC scale that corresponds to a score of 0 to 4 points, which
is a relatively easy scale for assessing dyspnea symptoms in the
community when compared to a CAT scores, on the other hand, the

mMRC scale makes more sense in emergency room visits or inpatient
visits. Using the mMRC scale and history of exacerbations, history of
admissions, we classified COPD into groups, group A accounted for
54.22%, group B 37.35%, group C and D accounted for less than 5%.
The results reflect the degree of disease in the community mainly fall
into groups of few symptoms.
In analyzing physical symptoms of subjects with COPD, we found that
hypertension (based on MOH standards: systolic blood pressure ≥ 140
mmHg or diastolic blood pressure ≥ 90 mmHg) accounts for 26.51%.
According to GOLD criteria, hypertension is quite common in COPD
and may be a prognostic factor, but it is unclear whether COPD is
independently associated with risk of hypertension or due to influences


21
of common risk factors such as age or smoking. Seon Hye Kim et al
(2017) studied 4043 men over 40 years old with spirometry, the
proportion of hypertension accounted for 54.2%. After adjusting for age,
smoking status, BMI...The authors found that COPD is independently
associated with hypertension, OR = 1.71 [95% CI, 1.37-2.13].
Physical examination signs such as barrel-shaped chest, increased
resonance to percussion, decreased breath sounds, wheezes, crackles at the
lung bases are very typical signs of COPD, but physical signs often appear in
late stages when ventilation functions has been greatly declined. In our
study, we found that 4.22% of the subjects had thoracic deformity,
decreased breath sounds seen in 60.84% and wheezing, coarse crackles
on auscultation was only seen in 25.9%, which is consistent with the
disease stage in the community with 78.31% subjects were in the
GOLD1-2 stage. Our results are similar to Phan Thu Phuong (2010) with
38.9% decreased breath sounds, 34.7% of increased resonance to

percussion, lung rales on auscultation accounting for 12.5%.
4.2.2. Characteristics of spirometry
When analyzing the spirometry of COPD subjects, we found that the
average FEV1 decreased (67.2% of the theoretical value); Mean
FEV1/FVC ratio 54.54%, not increase or not increased significantly after
bronchodilator test, this is consistent with the diagnosis criteria of COPD.
MMEF, MEF75%, MEF50%, MEF25% are all significantly reduced
compared to the theoretical values (29.1%, 29.3%, 25.1%, 30.6%
respectively) and not improved after bronchodilator test.
4.2.3. ECG characteristics
It’s found abnormal ECGs accounting for 41.57%. In particular, the
most common abnormal findings on ECGs were atrial enlargement
accounts for 20.48%, followed by sinus tachycardia accounting for
19.28%, bundle branch block accounts for 4.22%, atrial fibrillation
3.61% and other abnormalities such as right ventricular enlargement, left
ventricle enlargement, atrioventricular block, myocardial ischemia all
accounted for less than 3%. There was a relationship between abnormal
ECGs and COPD classification according to the degree of airway
obstruction, p <0.01. The rate of ECG abnormalities in our study is low,
partly because most patients with COPD in the community have mild and
moderate airway obstruction, and the rate of hypertension in COPD
patients only accounted for 26.51%. This result is also consistent with
other studies when evaluating ECG abnormalities in patients with mild
and moderate stages of COPD.
4.3. Assess the effectiveness of interventions for people with COPD
4.3.1. Effectiveness of intervention in terms of clinical characteristics


22
The effect of smoking cessation: the number of smokers

significantly decreased in the intervention group compared to the control
group, maybe these patients were diagnosed for the first time and haven't
knew that smoking is the cause of the disease. On the other hand, the number
of current smokers in our study is less, the intervention effect will be more
concentrated and there will be more time to counseling for each case.
The effectiveness of therapeutic interventions is to raise people's
awareness about the importance of maintenance treatment in the stable
stage and the risk of death if there are many exacerbations and frequency
of hospitalizations. In our research, patients are often called by research
team to check adherence to treatment, the amount of medications being
regularly used, to provide medical advice and/or to prescribe appropriate
affordable medication. Within 12 months, the number of patients develop
acute exacerbations as well as hospitalizations significantly decreased
compared to the control group, this may be due to good treatment
adherence, well implemented risk prevention methods as well as home
treatment in mild cases.
4.3.2. Evaluate the technique of using the inhaler dispensing devices
Before intervention, the number of patients who used pMDI and
Turbuhaler was very little, mainly concentrated in the group that was
diagnosed and treated at the tertiary level, most patients did not perform
all the important steps correctly. We provide patients with posters that
give instructions on how to use pMDI and Turbuhaler correctly, show
them videos and let them practice using on sample equipment. The
intervention group was re-evaluated on performing steps after 1 month
and 3 months at the commune health station, the patients continued to be
guided by one-on-one methods including technical observation, guide to
correct errors on important steps. We found that patients often make
mistakes in the step "place mouthpiece between lips" and perform
reversed the step "Take a deep breath-in and press the tip of Turbuhaler
concurrently" before spraying for pMDI and forgetting to hold the breath

for 10 seconds for pMDI and Turbuhaler.
In our study, some subjects in both groups still used LABA/ICS that
were not suitable with the stage of disease, while COPD group D
accounted for only 4.82%. This may be due to the shortage of LABA ±
LAMA, due to prescribing habits, habit of self-purchasing drugs or
popularity of LABA/ICS locally.
4.3.3. Assess the level of adherence
In our study, the rate of re-examination at commune, district and
tertiary levels is quite low. The rate achieved from 80% of visits/year
(from 10 visits/12 months) in the intervention group was 24.24%, the


23
control group was 9.38%. In fact, patients who are re-examined at commune
level are not provided with spray-inhaled bronchodilators (mainly
salbutamol, theophyline, theostat tablets), while district hospitals often
provide generic medicines to patients, only provincial level hospitals
provided brand-name drugs. On the other hand, due to difficult travel
conditions, awareness of patients is still low, the affordability of health
insurance is limited, leading to low compliance with re-examination.
Assessing adherence to medication is an important factor in
determining whether a patient is taking medication in accordance with a
doctor's instructions. Currently, many studies use Morisky's self-filled
questionnaire that consist of 8 items to assess the extent of adherence.
Morisky classification results in our study: good adherence with 31.82%
(intervention group) and 9.38% (control group), average adherence of 37.88%
(intervention group) and 20.31% (control group), poor adherence with 30.30%
(control group) and 70.31% (control group), p <0.0001.
The percentage of patients complied is quite low, many patients stop
taking medication once the clinical signs improved or forgot to use or run

out of drugs when they could not buy or be granted medication.
Om investigating the reasons for the low compliance rate, we found
that most studied patients with COPD are in the group A and B that had few
clinical symptoms so they did not want to use the drug, on the other hand,
some patients cannot afford to pay for drugs or no re-examination book is
made (usually at the beginning of the year when the book is transferred).
CONCLUSION
1. Epidemiology of COPD in Nghe An province
1.1. Prevalence of COPD in Nghe An province in people aged 40 and over
The prevalence of COPD in people aged 40 and over is 4.15%, in
men 8.43% and women 1.07%. The plain district (Dien Chau) has the
highest prevalence of COPD with 5.02% and the lowest prevalence in the
mountainous district (Tan Ky) with 3.56%. The proportion of patients
diagnosed with COPD for the first time is 93.34%.
1.2. The risk factors for COPD
Men are 3.2 times more likely to have COPD than women. Smokers
are 10.2 times more likely to have COPD than non-smokers, the higher
the level of pack-years smoking, the higher risk of COPD. Other risk
factors such as exposure to kitchen fumes ≥ 30 years and occupational
dust ≥ 20 years have a significant influence on COPD in this study,
corresponding to OR = 3.7 and 16.3, respectively. In addition, people
with a history of chronic respiratory disease, advanced age is also the risk
factor for COPD.
2. Clinical and laboratory characteristics of COPD patients


24
2.1. Clinical characteristics
Chronic cough and sputum production are the most common
symptoms, account for 62.65%, 52.41%, respectively; dyspnea and chest

tightness accounted for 45.78% and 37.35%, respectively. The majority
of patients with COPD are in group A and B (accounting for 82.57%).
26.51% of COPD patients have concurrent hypertension; 60.84% of
patients with decreased breath sounds, 25.9% of patients have rales.
2.2. Characteristics of ventilatory functions on spirometry
Classification of airway obstruction according to GOLD 1 and
GOLD 2 accounted for 78.31%. Mean FEV1/FVC ratio 54.8% ± 10 postbronchodilator test, reduction in men than in women, p <0.05.
2.3. ECG characteristics
Abnormal ECGs accounted for 41.57%, the most common was right
atrial enlargement (20.48%), sinus tachycardia (19.28%), right bundle
branch block (4.22%), atrial fibrillation (3.61%), ... Severe and very
severe airway obstruction has risk of abnormal ECG 2.77 times higher
than mild and moderate obstruction group, p <0.01.
3. Results of intervention for patients with COPD after 12 months
130/166 patients completed the study after 12 months (accounting
for 78.3%).
The smoking cessation rate in the intervention group decreased from
16.67% to 3.03%, there was a significant difference compared to the
control group, p <0.001.
The reduction in clinical symptoms of cough and sputum production
was not significantly differ between 2 groups, p> 0.05.
Average number of exacerbations, hospital admissions and mean
hospitalizations due to acute exacerbations in the intervention group
decreased significantly compared to the control group, p <0.05.
The rate of using pMDI and Turbuhaler increased in both groups,
the intervention group increased the number used and less misperforming
important steps compared to the control group, p <0.05.
The rate of periodic re-examination and adherence to using
bronchodilators in the intervention group is higher than the control
group, p <0.05.