Nepal Journ

Background: Tuberculosis (TB) is one of the major public health problems in Bhutan. Evaluation of treatment outcomes of TB and identification of the risk factors are important components for the success of National TB control program. Therefore, this study was undertaken to assess the TB treatment outcome and factors associated with it in Samtse General Hospital. Methods: This was a retrospective, cross sectional study using the TB data from Samtse General Hospital from 2008–2019. A univariate and multiple logistic regression was used to check for associations between the outcome and other independent variables. Results: The study included a total of 634 TB patients. Of this, 44.0% (279) were smear positive TB (PTB+), 36.1% (229) were extra pulmonary TB (EPTB) and 19.9% (126) were smear negative TB (PTB-). During the study period, 56.2% (356) of them completed treatment, 33.3% (211) were declared cured, 0.2% (1) had defaulted, 5.1% (32) died and 5.4% (34) had treatment failure. The mean treatment success rate (TSR) was 89.4% (567). The TSR was highest for EPTB with 96.9% (222/229), followed by PTBat 88.1% (111/126) and lowest for PTB+ with 83.9% (234/279). Successful treatment outcome was observed in EPTB patients (AOR: 7.3; 95% CI: 2.46-21.36), patients in age 15-28 years (AOR: 3.4; 95% CI: 1.59-7.46) and 29-42 years (AOR: 9.1; 95% CI: 2.44-33.61). Conclusion: The treatment outcome of TB in Samtse General Hospital is satisfactory and at par with the national level. Since, smear positive TB and elderly patients are prone to develop poor treatment outcome, they need to be monitored and followed up adequately.


Introduction
Globally, around one billion over the age of 25 years were diagnosed with hypertension in 2008 [1].Hypertension is defined as an increase in systolic blood pressure above 140 mmHg and/or diastolic blood pressure equal to or above 90 mmHg [2,3].Its prevalence is more in low and middleincome countries compared to high-income countries [3].It is responsible for 45% of deaths due to heart diseases [4].Hypertension is caused by both modifiable and non-modifiable risk factors [3].Modifiable predisposing factors include hyperlipidaemia [5], physical inactivity [6], obesity, kidney disease [7], diabetes, high salt intake [8], alcohol consumption [9,10], and smoking [11].Age, ethnic background and gender (female) are important non-modifiable risk factors of hypertension [10].Effective intervention includes early detection and treatment of hypertension, increased physical activity; reduce salt intake, moderate alcohol consumption, and cessation of smoking.In the last two decades, Bhutan has undergone a marked nutritional transition [12].This has resulted in increased disposable income levels and change in food habit with more consumption of saturated fat and salt diet from a traditional low-fat and low-salt diet.Furthermore, people engage in sedentary lifestyle with less physical activity [13].Rapid urbanisation in last two decade resulted in rural-urban migration and >31% of Bhutanese now live in urban areas.An earlier study reported a national prevalence of hypertension to be 17.1% in 2007 [14], while in the capital city Thimphu it was estimated at 26.0% [15].However, there is a lack of study on the national prevalence of hypertension and its associated correlates.Therefore, this study aims to determine the prevalence of hypertension and explore the correlates of hypertension in the Bhutanese population.Exploration of such data in Bhutan is anticipated to provide associated correlates for hypertension in a population undergoing the epidemiologic and nutrition transition.

Methodology Study design and participants
A secondary retrospective study was undertaken using the National Health Survey (NHS 2012) data.The Ministry of Health of Bhutan used the Surveillance of non-communicable diseases (STEP) survey guidelines to collect the data in all the 20 districts of Bhutan.The census sample frame for the NHS 2012 was developed using the Population and Housing Census of Bhutan 2005.

Inclusion criteria
The records of participants above the age of 18 years were extracted from the NHS data for analysis.

Exclusion criteria
Records with incomplete data were excluded from the final analysis.

Data collection
The data were obtained from the Ministry of Health data repository.District poverty was obtained from the Bhutan Multidimensional Poverty Index 2012 published online by the National Statistical Bureau (NSB) of Bhutan [16].The data were then linked to the proportion of hypertension by districts to examine the relationship between hypertension and poverty.

Sample size calculation
The sample size was calculated for each district using the following formula: Where: n is the required number of households; z is the value of the statistic in a normal distribution for a 95% confidence interval (this value is 1.96 and for purposes of calculation it is rounded to 2); p is the proportion of households within 1 hour to any health facility; e is the margin of error in calculating p, (was 0.05 for this study); f is the sample design effect, assumed to be 2.0; and k is an anticipated non-response of 5%.A total of 13,600 households were sampled corresponding to 45,635 individuals aged between 10-75 years.

Outcome variable
The dependent variable was self-reported hypertension on medication.The participants in this study were the adult population above 18 years.Independent variables were selfreported correlates obtained from the STEPS survey questionnaire.

Independent variable
Independent variables of interest were age, sex, education level, occupation, urban-rural residence, ever smokers, ever consumed alcohol, vigorous exercise, vegetable servings per day and feeling of worried.This study included all records of participants older than 18 years.One standard vegetable serving was defined as: (a) 1 cup of raw green leafy vegetable such as spinach, salad greens, etc.(b) ½ cup of other vegetables, cooked or chopped, such as carrots, pumpkin, corn, beans, onion, etc., but excluding tubers such as potatoes.A "standard drink" was quantified through the amount of ethanol in standard glasses of beer, fortified wine such as sherry, wine, and spirits (around 8-13 grams).Worried was defined as a feeling of stress resulting in an inability to sleep at night in the last 12 months.Vigorous activity was defined as any activity that increased heart rate/breathing as in lifting heavy loads, or similar to digging a field for 10 minutes.Hypertension was ascertained by recording medications which lower high blood pressure [17].

Characteristics of the study population
A total of 31,066 participants aged 18-75 years were extracted from the NHS 2012.The mean age of the survey participants was 39.3 years (95% confidence interval [CI] 39.2, 39.5) and there were 16,731 (53.9%) women.Twenty-six percent of the participants were in 25-34 age group and 24.6% lived in urban areas.Nearly half of the study population did not have formal education and <1% were diploma or certificate level educated.Two-third were married and 59.8% were farmers.The prevalence of diabetes in the survey was 1.8%.Forty-seven percent and 4.2% drank alcohol and smoked, respectively.Vegetables were consumed by 41.0% in a week.Only 1.0% of participants were always worried.More than 47.4% of the study participants were involved in the physical activities resulting in increased breathing (Table 1).

Socio-demographic characteristics of hypertensive patients
The national prevalence of hypertension was 17.4% and female constituted 62.3% of the study population.Nearly 11.4% of hypertensive patients were >64 years.Most (76.7%) hypertensive people lived in rural Bhutan.Married participants and those with no formal education made up 81.5% and 59.4% of study participants.Most of the hypertensive patients were farmers, unskilled and clerical workers, 5.7% has concurrent diabetes, and nearly half-consumed alcohol (48.5%), 3.3% were current smokers and 17.1% ever smoked.Only 3.3% did consume vegetables in a typical week, while 40.2%, 29.2% and 27.3% consumed vegetables in 6-7, 4-5 and 1-3 days respectively.More than half of the participants were never worried or felt lonely.Forty-six percent of hypertensive participants engaged in vigorous physical activity (Table 1).The proportion of hypertensive participants ranged from 10.7% to 22.0% with Paro, Punakha and Trashigang districts reporting a higher proportion of hypertension (Figure 1).There was a significant negative association between the proportion of hypertension and district poverty level in the Pearson correlation analysis (r=-0.4831,p=0.0309).

Discussion
The national prevalence of hypertension was 17.4% and the factors associated with hypertension were age, female, being a single, occupation in armed forces, managers, salespersons, technicians and monks, having diabetes and being worried.

Prevalence of hypertension
Hypertension is one of the top five non-communicable diseases in Bhutan [21].Uncontrolled and untreated hypertension can lead to a number of complications such as heart failure, renal diseases, ischemic heart disease, pulmonary hypertension and cerebrovascular diseases including stroke [22].Globally, it is responsible for significant disability and premature deaths [4].Further, medical expenses in managing hypertension associated complications results are huge [23][24][25].Therefore, this nationally representative first epidemiological study is timely and provides much-needed evidence to policymakers of Bhutan to initiate prevention strategies for hypertension.

Risk factors of hypertension
As in other studies, women were at high risk of hypertension compared to men [26][27].As the women reach menopause, the protection offered by oestrogen decreases thereby increasing the risk of hypertension [28,29].In this study, age was an important non-modifiable risk factor for hypertension which is in conformity with the published literature [30].The life expectancy of the Bhutanese population has increased from 48 years in 1975 to 69 years in 2008.This increase is due to the introduction of modern health facilities in the 1960s [31,32].As population ages, many pre-hypertensive populations will progress to full hypertension in the absence of appropriate preventive measures including screening and pharmacological management.
Diabetes was associated with hypertensive in other studies [33][34].This is due to the shared risk factors such as sedentary lifestyle and obesity [35], smoking and alcohol use, and share a common metabolic pathway [36].Diabetes in general Bhutanese population was around 1.8% [17,37].Therefore, national preventive strategies should take a holistic approach incorporating both hypertension and diabetes.
In this study, occupations with less physical activity including monks were at risk of hypertension as compared to jobs that require physical activity.Such findings were reported in other studies from our region [38][39].The finding that monks are at higher risk of hypertension is important because there is a large number of monks in the monasteries, and most of these monasteries do not engage in regular physical activities since appropriate facilities are not readily available.Preventive measures including regular physical activity need to be initiated, targeting these groups of people.Hypertension was associated with poor mental health including anxiety [40,41].The pathway between anxiety and hypertension is complex.Anxiety can increase blood pressure in the short term.For instance, a phenomenon of increased blood pressure due to the white coat effect associated anxiety is well known [42,43].Other pathways that increase blood pressure due to anxiety include a change in the systemic vascular resistance, sympathetic activity, plasma renin activity, the homeostasis model and blood lipids [44][45].An indirect association between hypertension and anxiety could be related to the characteristics of anxious subjects-who may engage in an unhealthier lifestyle including increased food intake, smoking, alcohol use, and sedentary lifestyle due to stress and anxiety [46].The risk of hypertension increased with the decreasing level of poverty in this study.This is also evident from the hypertension distribution map of Bhutan.This finding is supported by previous studies from India and Nepal [47,48], but contrary to other published literature [49,50].A plausible reason could be-increased disposable income led to increased buying capacity of fatty, energy-dense processed foods and engage in sedentary lifestyle by the wealthier people.

Conclusion
The study provides a nationally representative hypertension prevalence of 17.4%.Hypertension was associated with age, being women, occupation with less physical activity, being worried and diabetes.The preventive measures both at community and health facility-based through cost-effective strategies should target these covariates.

Limitation of the study:
This study has some limitations, firstly, the cross-sectional study design cannot establish a causal relationship.Secondly, hypertension status was self-reported so respondents were subjected to probable recall bias and could not be validated and are generally underreported [51].However, this recall bias could be minimal since they were those on medication.
Thirdly, only hypertensive individuals on medication were included in the study and missed those who were asymptomatic or undiagnosed.Fourthly, self-reported behavioural habits such as vegetable consumption, smoking, alcohol use and physical activity were likely to over or underreported as a result of social desirability.Finally, the data for this data is rather old and the trends might have changed over time.Nevertheless, it is the first study on the prevalence of hypertension and its correlates in the Bhutanese population using nationally representative data.Therefore, the findings from this study can be used for national preventive strategies in Bhutan.
Future scope of the study: Hypertension prevalence in Bhutan was high.The identified risk factors were age, being women, occupation with less physical activity, being worried and diabetes.Therefore, Bhutan should initiate regular screening programmes to detect hypertension in the older population.In addition, it is recommended to undertake prospective studies to monitor the trends of hypertension and identify the associated risk factors.

What is already known on this topic?
Previous studies on hypertension were done in the capital city Thimphu only.The risk of hypertension increased with age but other risk factors were not explored.

What this study adds:
This study presents nationally representative hypertension in adult Bhutanese.The identified risk factors in this study can be used to target preventive measures.Further, the findings can be used as a baseline to access the effectiveness of any preventive measures in the country.Authors' affiliations:

Data management and statistical analysis:
The ethical approval for this study was provided by the Research Ethics Board of Health (REBH), Ministry of Health Bhutan via REBH/Approval/2018/041.

Table 2 : Bivariate logistic regression analysis with the correlates of hypertensionTable 3 : Multivariate logistic regression analysis with risk factors for hypertension
1Research Fellow, Department of Global Health, Research School of Population Health, The Australian National University, Canberra, Australia.