Abstract
This study examines the prevalence, awareness, treatment, and control of hypertension in Ulaanbaatar, Mongolia, using both the American Heart Association and conventional thresholds (130/80 and 140/90 mm Hg, respectively). In this randomized cross‐sectional study, two‐stage cluster sampling was used to obtain a sample of 4515 individuals aged ≥20 years. Hypertension was defined by the use of antihypertensives in the last 2 weeks or a blood pressure at or above the thresholds of 140/90 and 130/80 mm Hg. The mean age of the participants was 41.1 ± 14.0 years and 54.5% were women. Hypertension prevalence was 25.6% (using 140/90 mm Hg) and 46.5% (using 130/80 mm Hg). Prevalence increased with age and below 50 years men were consistently more likely to be hypertensive. Among hypertensive participants, the rates of awareness, treatment, and control were 69.7%, 46.8%, and 24.0% (using 140/90 mm Hg) and 49.1%, 25.8%, and 6.4% (using 130/80 mm Hg, respectively). Men had lower rates of awareness, treatment, and control compared with women, with the most pronounced differences at younger ages. This study shows that awareness, treatment, and control rates in Ulaanbaatar are better than in most low‐ and middle‐income countries but are still suboptimal. The largest “care gap” was in young men where a regulatory requirement for annual workplace blood pressure screening has the potential to enhance care. A major hypertension control program has just been initiated in Ulaanbaatar.
Keywords: hypertension awareness, hypertension control, hypertension prevalence, hypertension treatment
1. INTRODUCTION
Increased systolic blood pressure is the leading single risk for cardiovascular disease (CVD) and overall mortality worldwide and in Mongolia.1, 2 Hypertension is the major risk factor for stroke and precedes hemorrhagic stroke in as many as 80% of all hemorrhagic stroke cases.3 This makes hypertension a particularly important public health issue in Mongolia which has one of the highest mortality rates from hemorrhagic stroke in the world.2, 4 Hypertension prevalence in low‐ and middle‐income countries (LMICs) is increasing faster than in high‐income countries (HICs), yet hypertension awareness, treatment, and control in are much lower and increasing at a slower rate.5
The Better Hearts Better Cities (BHBC) initiative (Novartis Foundation) aims to reduce the burden of CVD in Ulaanbaatar through a focus on hypertension control.6 With over 1.45 million people, Ulaanbaatar is the most populous city in Mongolia and represents 45.7% of the national population.7 The prevalence of hypertension in Mongolia has previously been measured using the World Health Organization (WHO) STEPwise approach to Surveillance of noncommunicable diseases (STEPS) methodology, most recently in 2013, but these measurements are not specific to Ulaanbaatar.8 Furthermore, new hypertension guidelines were published in 2018 from the Ministry of Health, Mongolia, which changed the threshold of hypertension from 140/90 to 130/80 mm Hg to match that published in 2017 by the American Heart Association (AHA), and the results of past surveys are no longer applicable when using this new definition.9
We performed a STEPS‐like cross‐sectional population‐based blood pressure survey to provide updated and accurate information about the baseline prevalence of hypertension and rates of awareness, treatment, and control of hypertension in Ulaanbaatar before the BHBC intervention, using both the conventional (140/90 mm Hg) and newer (130/80 mm Hg) definitions of hypertension.10 BHBC has also reported the baseline knowledge, attitudes, and practices (KAP) of health care professionals.11, 12 A multisectoral hypertension control program designed along the lines of the World Health Organization HEARTS program has been developed and is currently being launched.13, 14 This survey is designed to highlight the clinical care gaps (ie, lack of awareness of diagnosis, lack of treatment of those diagnosed, and lack of control in those treated) which along with the KAP survey results have been used to prioritize the hypertension control interventions of BHBC.
2. METHODS
2.1. Population
The target population consisted of all individuals aged 20 years or older living in Ulaanbaatar, Mongolia. The sample size needed was based on guidance from the WHO STEPS Surveillance Manual.10 The figure for hypertension prevalence (140/90 mm Hg threshold) from the previous STEPS study in Mongolia in 2013 was 26.7%, and this was selected for the estimated baseline level.8 To report different estimates for age and sex, we created eight age‐sex categories (20‐29, 30‐39, 40‐49, and 50+ years for men and women). For a confidence level of 1.96 (associated with a 95% confidence interval), a margin of error of 0.05, a design effect of 1.50, and an anticipated response rate of 80%, a sample size of 4511 was required.10
Two‐stage cluster sampling was used to select individuals, first sampling geopolitical units and then sampling individuals within these units. Family health care centers (FHCCs), of which there are 142 in Ulaanbaatar, provide primary health care services to all citizens. The WHO STEPS Surveillance Manual recommends that at least 50 primary sampling units (PSUs) are selected from over 100.10 Every citizen is registered at their local FHCC, and thus, FHCCs were appropriate to serve as PSUs with which to sample from the general population. One district, Bagakhangai, was excluded because it was geographically isolated and had a small population, and 25 FHCCs were excluded because they were being used to develop and test the BHBC hypertension control training program. Following this, proportional probability sampling was used to select 52 FHCCs, from the eight districts in the first stage of cluster sampling.
In the second stage, 88 individuals aged 20 years or over were randomly selected from the registers of each of the 52 FHCCs. Only Mongolian citizens registered for 6 months or longer were considered to meet the inclusion criteria. If participants could not be reached by the research team, they were replaced by the next participant within the same age and sex category.
2.2. Data collection
Before data collection, all field members successfully completed a training program on conducting the interview and measuring blood pressure. A pilot study was conducted on five randomly selected FHCCs in November 2017. The data collection process was conducted between December 2017 and January 2018. In total, 4515 participants were included in the sample.
The entire data collection procedure was conducted on an electronic tablet (Fire HD 8, Amazon). To avoid data loss, an android application with an offline mode, QuickTapSurvey (TabbleDabble Inc), was used.
Interviews were conducted using a Mongolian version of the WHO STEPS Instrument for Noncommunicable Disease Risk Factor Surveillance.10 To ensure the adequacy of the Mongolian translation of questionnaires, the Mongolian language versions were separately back‐translated by two independent translators and reviewed.
Finally, blood pressure was measured using the accuracy‐validated BP A6 BTs (Microlife Corporation), digital automatic blood pressure monitors.15 Participants were instructed to abstain from alcohol, cigarette smoking, caffeine consumption, and exercise for at least 30 minutes before blood pressure measurement. Data collection teams ensured that participants were seated with legs uncrossed and back and arm supported, in accordance with the American Heart Association (AHA) guidelines, and used appropriate cuff sizes.16 After a 10‐minute rest, blood pressure was measured three times, with 3‐minute interval between the measurements.
2.3. Ethical considerations
This study was fully approved by the Medical Ethics Committee, Ministry of Health, and Expert Committee at the School of Public Health, Mongolian National University of Medical Sciences. An informed consent form was obtained from each participant before the interview and physical measurements.
2.4. Definitions
Two different thresholds were used to define hypertension: the conventional definition of a mean SBP ≥ 140 mm Hg or a mean DBP ≥ 90 mm Hg as recommended by the WHL, and the newer definition of mean SBP ≥ 130 mm Hg or a mean DBP ≥ 80 mm Hg in line with the updated 2017 AHA guidelines.9, 17 Participants were classified as hypertensive if either BP reached the hypertension threshold or responses to a standard questionnaire indicated that prescribed antihypertensive medication had been taken in the last 14 days.
Definitions of hypertension awareness, treatment, and control were based on recommendations from the WHL.17 All hypertensive participants were classified as either unaware, aware but untreated, treated but uncontrolled, or controlled as follows:
Participants were classified as unaware if blood pressure reached the hypertension threshold and questionnaire answers showed that they had never been diagnosed with hypertension.
Participants were classified as aware but untreated if blood pressure reached the hypertension threshold and questionnaire answers showed that they were aware of a diagnosis of hypertension but had not taken prescribed antihypertensives in the last 14 days.
Participants were classified as treated but uncontrolled if questionnaire answers showed that they had taken prescribed antihypertensives in the last 14 days and blood pressure reached the hypertension threshold.
Participants were classified as controlled if questionnaire answers showed that they had taken prescribed antihypertensives in the last 14 days and blood pressure did not reach the hypertension threshold.
2.5. Data analysis
Data analysis was performed in SPSS Statistics version 25 (IBM). Age was presented as mean ± standard deviation (SD). Frequencies were presented with a percentage. For analysis of blood pressure, the first of the three recordings was discarded and the average of the last two recordings was used. If one of the blood pressure recordings was missing, the other two were used. For both systolic blood pressure (SBP) and diastolic blood pressure (DBP), both the mean with SD and the median with first and third quartiles were reported as recommended by the World Hypertension League (WHL).17 Hypertension prevalence, awareness, treatment, and control were expressed as percentages with 95% confidence intervals (CIs). All 95% CIs were generated by bootstrapping using 1000 samples. Percentages were compared using two‐tailed independent‐samples t tests. After presenting crude overall data, results were also weighted for age and sex using the 2015 Population and Housing By‐Census of Mongolia, to ensure results were representative of the population.7
3. RESULTS
3.1. Demographic information
In total, 4515 participants were included in the sample. The overall response rate of those listed in the registry consenting and participating was 45%. The mean age was 41.1 (±14.0) years: 40.3 (±14.0) years for men and 41.7 (±14.1) years for women. The absolute number of participants from each age‐sex category in the sample compared with data from the 2015 Population and Housing By‐Census of Mongolia is shown in Table 1.7
Table 1.
The absolute number and percentage of the sample in each age‐sex category compared with results from the 2015 Population and Housing By‐Census of Mongolia7
| Age‐sex category | Sample (n) | Population (n) |
|---|---|---|
| Male | ||
| 20‐29 | 548 (12.1%) | 135 117 (15.0%) |
| 30‐39 | 568 (12.6%) | 116 883 (13.0%) |
| 40‐49 | 415 (9.2%) | 81 954 (9.1%) |
| 50+ | 523 (11.6%) | 85 001 (9.5%) |
| Female | ||
| 20‐29 | 620 (13.7%) | 144 713 (16.1%) |
| 30‐39 | 598 (13.2%) | 127 188 (14.1%) |
| 40‐49 | 519 (11.5%) | 94 000 (10.5%) |
| 50+ | 724 (16.0%) | 114 265 (12.7%) |
| Both sexes | ||
| 20‐29 | 1168 (25.9%) | 279 830 (31.1%) |
| 30‐39 | 1166 (25.8%) | 244 071 (27.1%) |
| 40‐49 | 934 (20.7%) | 175 954 (19.6%) |
| 50+ | 1247 (27.6%) | 199 266 (22.2%) |
| Age 20+ | ||
| Male | 2054 (45.5%) | 418 955 (46.6%) |
| Female | 2461 (54.5%) | 480 166 (53.4%) |
| Overall | 4515 (100%) | 899 121 (100%) |
Our sample slightly underrepresented those in the younger age groups and overrepresented those in older age groups. The proportions of men and women in the sample and the population were very similar. To account for any differences, overall results were weighted for both age and sex. The frequencies of other demographic characteristics are shown in Table S1.
3.2. Distributions of SBP and DBP
The overall mean blood pressure for the sample population when weighted for age and sex was 122/78 mm Hg. Blood pressure increased with age from 116/73 mm Hg (20‐29 years) to 133/84 mm Hg (50+ years). Mean blood pressure was also higher in men than in women: 128/82 mm Hg among men vs 119/76 mm Hg among women (Table 2).
Table 2.
The distributions of systolic blood pressure (SBP) and diastolic blood pressure (DBP) in each age‐sex category
| Age‐sex category | SBP (mm Hg) | DBP (mm Hg) | ||
|---|---|---|---|---|
| Mean | Median | Mean | Median | |
| Male | ||||
| 20‐29 | 123 (±12) | 123 (115‐130) | 76 (±9) | 76 (70‐81) |
| 30‐39 | 126 (±14) | 124 (117‐134) | 82 (±10) | 81 (75‐88) |
| 40‐49 | 129 (±15) | 128 (120‐138) | 86 (±10) | 86 (78‐93) |
| 50+ | 135 (±20) | 132 (121‐148) | 87 (±12) | 86 (78‐94) |
| Female | ||||
| 20‐29 | 110 (±10) | 110 (103‐117) | 70 (±8) | 70 (64‐75) |
| 30‐39 | 112 (±13) | 111 (104‐119) | 73 (±9) | 72 (67‐78) |
| 40‐49 | 120 (±17) | 117 (109‐130) | 78 (±11) | 77 (71‐85) |
| 50+ | 132 (±19) | 129 (118‐144) | 81 (±11) | 80 (74‐88) |
| Both sexes | ||||
| 20‐29 | 116 (±13) | 115 (107‐124) | 73 (±9) | 73 (66‐78) |
| 30‐39 | 119 (±15) | 118 (109‐128) | 77 (±11) | 76 (52‐136) |
| 40‐49 | 124 (±17) | 123 (112‐134) | 82 (±11) | 81 (73‐89) |
| 50+ | 133 (±20) | 131 (119‐146) | 84 (±12) | 83 (75‐91) |
| Age 20+ | ||||
| Male | 128 (±16) | 126 (117‐137) | 82 (±11) | 81 (75‐89) |
| Female | 119 (±18) | 116 (107‐128) | 76 (±11) | 74 (68‐83) |
| Overall (crude) | 123 (±17) | 121 (111‐133) | 79 (±12) | 78 (71‐86) |
| Overall (weighted) | 122 | ‐ | 78 | ‐ |
3.3. Prevalence of hypertension
The overall weighted prevalence of hypertension was 25.6% when using a 140/90 mm Hg threshold and 46.5% when using a 130/80 mm Hg threshold. Hypertension prevalence increased with age. Comparing the 20‐29 years and 50+ years age categories, hypertension prevalence was significantly greater in the older age category whether using the 140/90 mm Hg threshold (7.7% vs 57.3%, P < .0001) or using the 130/80 mm Hg threshold (25.1% vs 73.8%, P < .0001). Furthermore, hypertension prevalence was significantly higher in men than in women, whether using the 140/90 mm Hg threshold (31.9% vs 25.5%, P < .0001) or the 130/80 threshold (60.5% vs 39.6%, P < .0001) (Table S2).
Although there were relatively small differences in hypertension prevalence between men and women in the 50+ years category (Figure 1, 140/90: P > .05; 130/80: P < .01), hypertension was substantially more common in men than women in the other age categories (Figure 1, 20‐29, 30‐39, and 40‐49 years using a 140/90 threshold: P < .0001, P < .0001, and P < .0001, respectively; using a 130/80 threshold: P < .0001, P < .0001, and P < .0001, respectively).
Figure 1.
The prevalence of hypertension in each age‐sex category for both the 140/90 mm Hg (A) and 130/80 mm Hg (B) thresholds with 95% confidence interval error bars
3.4. Awareness, treatment, and control of hypertension
Among those with hypertension according to the 140/90 mm Hg threshold, overall weighted figures indicated that 30.3% were unaware they had hypertension, 24.1% were aware they had hypertension but not on antihypertensive drug treatment, 22.8% were on antihypertensive drug treatment but their hypertension was not controlled, and 24.0% were on antihypertensive drug treatment and had their hypertension controlled. Using a 130/80 mm Hg threshold, these figures were 50.1% unaware, 23.3% aware but untreated, 19.4% treated but uncontrolled, and 6.4% treated and controlled.
Comparing the youngest (20‐29 years) and oldest (50+ years) participants with hypertension, a greater proportion of the younger participants were unaware of their diagnosis (140/90: 51.7% vs 17.0%, P < .0001; 130/80: 72.6% vs 29.7%, P < .0001) and a greater proportion of the older participants were controlled (140/90 mm Hg: 31.7% vs 21.3%, P < .05; 130/80 mm Hg: 10.7% vs 4.8%, P < .01). Additionally, a greater proportion of the older participants were on treatment but not controlled (140/90 mm Hg: 33.0% vs 6.7%, P < .0001; 130/80 mm Hg: 39.4% vs 3.8%, P < .0001). There was no significant difference in the proportion of older and younger participants who were untreated despite being aware they had hypertension (140/90 mm Hg: 20.2% vs 18.3%, P > .05; 130/80 mm Hg: 18.8% vs 20.2%, P > .05).
Comparing the sexes, a significantly greater proportion men than women with hypertension were unaware of their diagnosis (140/90 mm Hg: 41.1% vs 15.1%, P < .0001; 130/80 mm Hg: 59.3% vs 34.4%, P < .0001). Conversely, a significantly greater proportion of women had their hypertension controlled (140/90 mm Hg: 37.5% vs 13.0%, P < .0001; 130/80 mm Hg: 12.2% vs 2.6%, P < .0001). A significantly greater proportion of men than women were aware they had hypertension but untreated when using the 140/90 mm Hg threshold (25.9% vs 18.8%, P < .0001), but not when using the 130/80 mm Hg threshold (23.3% vs 23.1%, P > .05). Finally, a significantly greater proportion of women were on treatment that did not control their hypertension (140/90 mm Hg: 28.6% vs 19.9%, P < .001; 130/80 mm Hg: 30.3% vs 14.8%, P < .0001) (Table 3).
Table 3.
The percentages of hypertensive participants who were classified as unaware, aware but untreated, treated but uncontrolled, or controlled in each age‐sex category for both thresholds of hypertension
| Age‐sex category | Using 140/90 | Using 130/80 | ||||||
|---|---|---|---|---|---|---|---|---|
| Unaware (%) | Aware but untreated (%) | Treated but uncontrolled (%) | Controlled (%) | Unaware (%) | Aware but untreated (%) | Treated but uncontrolled (%) | Controlled (%) | |
| Male | ||||||||
| 20‐29 | 66.7 (55.0‐78.3) | 20.0 (10.0‐31.7) | 6.7 (1.7‐13.3) | 6.7 (1.7‐15.0) | 79.3 (73.7‐85.4) | 16.7 (11.1‐21.7) | 3.5 (1.5‐6.6) | 0.5 (0.0‐2.0) |
| 30‐39 | 51.0 (43.4‐58.6) | 31.0 (24.1‐38.6) | 9.7 (5.5‐14.5) | 8.3 (4.1‐13.1) | 69.2 (64.7‐74.3) | 23.1 (18.6‐27.2) | 6.0 (3.6‐8.7) | 1.8 (0.6‐3.3) |
| 40‐49 | 52.3 (44.5‐60.0) | 27.1 (20.0‐34.2) | 14.8 (9.7‐10.6) | 5.8 (2.6‐10.3) | 62.5 (56.8‐68.1) | 26.9 (21.6‐31.9) | 9.6 (6.3‐13.3) | 1.0 (0.0‐2.3) |
| 50+ | 25.0 (20.2‐30.5) | 24.0 (18.8‐29.1) | 30.5 (25.3‐36.3) | 20.5 (15.8‐25.0) | 39.0 (34.2‐43.4) | 24.1 (19.6‐28.3) | 31.5 (27.5‐36.2) | 5.5 (3.5‐7.7) |
| Female | ||||||||
| 20‐29 | 20.7 (6.9‐37.9) | 20.7 (6.9‐37.9) | 6.9 (0.0‐17.2) | 51.7 (34.5‐69.0) | 58.5 (48.9‐68.1) | 23.4 (14.9‐33.0) | 4.3 (1.1‐8.5) | 13.8 (7.4‐20.2) |
| 30‐39 | 21.8 (11.0‐32.7) | 29.1 (18.2‐40.0) | 9.1 (1.8‐16.4) | 40.0 (27.3‐52.7) | 52.1 (43.8‐60.3) | 29.5 (22.6‐37.7) | 7.5 (3.4‐12.3) | 11.0 (6.2‐16.4) |
| 40‐49 | 23.4 (16.9‐30.6) | 29.0 (21.0‐37.1) | 21.8 (14.5‐29.8) | 25.8 (18.5‐33.9) | 40.2 (33.8‐47.0) | 32.9 (26.5‐39.3) | 21.0 (15.5‐26.5) | 5.9 (2.7‐9.6) |
| 50+ | 11.4 (8.5‐14.5) | 14.3 (11.1‐18.1) | 34.8 (30.2‐39.4) | 39.6 (35.0‐44.4) | 22.4 (19.1‐26.1) | 17.1 (13.9‐20.2) | 45.6 (41.3‐50.1) | 14.9 (11.8‐17.9) |
| Both sexes | ||||||||
| 20‐29 | 51.7 (40.4‐62.9) | 20.2 (12.4‐29.2) | 6.7 (2.2‐12.4) | 21.3 (13.5‐30.3) | 72.6 (67.1‐77.7) | 18.8 (14.4‐23.6) | 3.8 (1.7‐5.8) | 4.8 (2.4‐7.5) |
| 30‐39 | 43.0 (36.0‐50.0) | 30.5 (24.0‐36.5) | 9.5 (5.5‐13.5) | 17.0 (12.0‐22.5) | 64.0 (59.4‐68.1) | 25.0 (21.3‐29.2) | 6.5 (4.4‐8.8) | 4.6 (2.7‐6.7) |
| 40‐49 | 39.4 (33.7‐45.2) | 28.0 (22.6‐33.0) | 17.9 (13.6‐22.6) | 14.7 (10.8‐19.0) | 53.1 (48.7‐57.1) | 29.4 (25.4‐33.7) | 14.4 (11.7‐17.7) | 3.1 (1.7‐4.6) |
| 50+ | 17.0 (14.6‐19.7) | 18.3 (15.4‐21.0) | 33.0 (29.9‐36.5) | 31.7 (28.2‐35.1) | 29.7 (26.6‐32.8) | 20.2 (17.4‐23.0) | 39.4 (36.3‐42.8) | 10.7 (8.8‐12.9) |
| Age 20+ | ||||||||
| Male | 41.1 (37.4‐44.8) | 25.9 (22.5‐29.4) | 19.9 (16.6‐23.0) | 13.0 (10.6‐16.0) | 59.3 (56.7‐62.2) | 23.3 (21.0‐25.7) | 14.8 (12.7‐16.8) | 2.6 (1.7‐3.5) |
| Female | 15.1 (12.4‐18.2) | 18.8 (15.8‐22.0) | 28.6 (25.2‐32.3) | 37.5 (33.9‐41.5) | 34.4 (31.4‐37.2) | 23.1 (20.6‐25.9) | 30.3 (27.1‐33.2) | 12.2 (10.1‐14.4) |
| Overall (crude) | 28.4 (25.9‐30.6) | 22.4 (20.2‐24.9) | 24.2 (21.8‐26.7) | 25.0 (22.5‐27.4) | 48.4 (46.3‐50.3) | 23.2 (21.6‐24.9) | 21.6 (20.0‐23.4) | 6.8 (5.8‐8.0) |
| Overall (weighted) | 30.3 | 22.9 | 22.8 | 24.0 | 50.9 | 23.3 | 19.4 | 6.4 |
The large difference between men and women in control of hypertension is largely because of a lack of awareness of hypertension among men. Furthermore, these differences in awareness and control are mostly accounted for by the younger age categories (Figure S1). Among hypertensive men aged 20‐29 years, 66.7% were unaware they had hypertension when using a 140/90 mm Hg threshold and 79.3% when using a 130/80 mm Hg threshold. However, among hypertensive women in this same age category, 51.7% were not only aware of their hypertension but on treatment and controlled when using a 140/90 mm Hg threshold. Women had higher rates of awareness and control than men in every age category, with the differences more pronounced among the younger age categories.
4. DISCUSSION
Compared with the average of LMICs, the prevalence of hypertension (using a 140/90 mm Hg threshold) is higher in Ulaanbaatar but the awareness, treatment, and control rates are also higher.18 On average, the prevalence, awareness, treatment, and control rates of hypertension for adults living in LMICs are 17.5%, 39.2%, 29.9%, and 10.3%, respectively, while corresponding rates in Ulaanbaatar are 25.6%, 69.7%, 46.8%, and 24.0%, respectively.18 The rates of hypertension prevalence, awareness, treatment, and control in Ulaanbaatar are in fact similar to the average of HICs (28.5%, 67.0%, 55.6%, and 28.4%, respectively).5 In order to explore whether this was due to recent improvement, we obtained data from the 2013 STEPS survey and calculated the hypertension prevalence, awareness, treatment, and control rates among adults aged 20 years or older in Ulaanbaatar using identical analytical methodology.8 The weighted results were 23.4%, 73.0%, 48.8%, and 18.8%, respectively, also similar to our results and the average of HICs. This suggests that the better‐than‐expected hypertension indicators must have been largely attained prior to 2013. This may reflect the impact of the Millennium Challenge Corporation, which ran a short‐term hypertension control program initiative in Mongolia from 2008 to 2013.19
Using a 130/80 mm Hg threshold for diagnosing hypertension has a marked influence on hypertension prevalence in Mongolia, as has been similarly documented in other countries.20, 21, 22, 23, 24 The prevalence of hypertension defined by the 130/80 mm Hg threshold increased to almost 50% of adults and awareness, treatment, and control rates were markedly lower.
This survey has the usual limitations of cross‐sectional population surveys. It is possible that the characteristics of the participants were different to those of the population. Although there was a slight underrepresentation of younger age groups and overrepresentation of older age groups, any differences in age‐sex distribution between the sample and the population were accounted for by the weighted analysis. However, a selection bias due to respondents having different characteristics from those who did not respond cannot be excluded, especially given the 45% response rate. The response rate was relatively consistent, between 41% and 46%, across all clusters of age, sex, and sampling location, and therefore conclusions drawn from comparison between these clusters will not have been affected by relative differences in response rate. As a further limitation, we recognize that this epidemiological method for determining the prevalence of hypertension does not strictly follow the AHA guidelines, recommending the diagnosis be made using an average from more than one occasion, which can lead to an overestimation of hypertension prevalence by around 12%.9, 25 The exclusion of a more isolated district also limits the generalizability of the survey findings to that specific population. However, the last national STEPs survey did not find substantive rural‐urban differences in hypertension indicators.8
Despite being better than expected, the rates of awareness, treatment, and control in Ulaanbaatar remain suboptimal. In Canada, a HIC, in 2012‐2013, the awareness rate was 84.3%, treatment rate was 79.6%, and control rate was 68.1%.26 Marked increases in hypertension control in Canada are attributed to a highly simplified, extensively disseminated, long‐term health care professional, and public education program.27 In Ulaanbaatar, a multisectoral intervention that includes extensive health care professional education, enhanced subsidies to medications, updated hypertension management guidelines, the use of a simplified diagnostic and therapeutic algorithm, and a registry with performance reporting is underway. The intervention is consistent with the HEARTS program which was developed with the leadership of the WHO.13, 14 The goal of the intervention in Ulaanbaatar is to achieve a hypertension control rate of 50% by 2025.
The findings above suggest that the main barrier to hypertension control is a lack of awareness of hypertension, particularly among younger men. This subpopulation was also identified as relatively vulnerable to adverse health outcomes due to hypertension by a 2013 national KAP study.28 No matter the definition of hypertension used, more than half of hypertensive men in any age category under 50 years were unaware they had hypertension. This is likely in part because men are less likely to access the health care system than women, and similar sex patterns are seen worldwide. However, Mongolian regulations provide a relatively unique opportunity to improve hypertension control: all workplaces must screen for hypertension, among other health risks, annually. By systematically linking this screening with hypertension management, the BHBC initiative could make significant improvements in hypertension control in Ulaanbaatar.
5. CONCLUSIONS
Hypertension control in Ulaanbaatar is a major civil health priority. The reported survey showed some surprising results in terms of better‐than‐expected hypertension awareness, treatment, and control rates. More research is required to examine when the hypertension control rate improved and the likely reasons for the surprising results. Nevertheless, the control rate remains suboptimal. The initial focus of the BHBC intervention is to enhance hypertension management in clinical settings and increase the capacity for such management and then subsequently integrate those identified by workplace screening. The Ulaanbaatar program is also being scaled nationally. Publication of the implementation of the BHBC is planned for the near future, as well as publication of the impact of the education intervention on KAP of health care professionals.
CONFLICT OF INTEREST
NRCC was a paid consultant to the Novartis Foundation (2016‐2017) to support their program to improve hypertension control in low‐ to middle‐income countries which includes travel support for site visits and a contract to develop a survey. NRCC has provided paid consultative advice on accurate blood pressure assessment to Midway Corporation (2017) and is an unpaid member of World Action on Salt and Health (WASH).
AUTHOR CONTRIBUTIONS
Harry Potts performed the analysis, drafted the manuscript, and designed the figures. Uurtsaikh Baatarsuren performed the analysis, performed the measurements, and processed the experimental data. Maral Myanganbayar performed the measurements and processed the experimental data. Baigal Purevdorj, Burtu‐Ujin Lkhagvadorj, Namuun Ganbat, Alimaa Dorjpalam, Delgerbat Boldbaatar, and Khatantuul Boldbaatar performed the measurements and were involved in planning. Khulan Tuvdendarjaa, Dulmaa Sampilnorov, Myagmartseren Dashtseren, Batbold Batsukh, Namkhaidorj Tserengombo, Tsolmon Unurjargal, Enkhtuya Palam, Roberta Bosurgi, and Geoffrey So were involved in planning and supervised the work. Norm R. C. Campbell, Andreas Bungert, and Naranbaatar Dashdorj aided in interpreting the results and worked on the manuscript. Naranjargal Dashdorj aided in interpreting the results, worked on the manuscript, was involved in planning, and supervised the work. All authors discussed the results and contributed to the final manuscript.
Supporting information
ACKNOWLEDGMENTS
We wish to thank all the students, nurses, and staff members of the Onom Foundation and Liver Center who worked tirelessly in the acquisition of these data.
Potts H, Baatarsuren U, Myanganbayar M, et al. Hypertension prevalence and control in Ulaanbaatar, Mongolia. J Clin Hypertens. 2020;22:103–110. 10.1111/jch.13784
Potts, Baatarsuren and Myanganbayar contributed equally as first authors.
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