Knowledge change related to hypertension in the Southern province of Vietnam: a community based, before and after intervention evaluation

Hypertension is a key modifiable risk factor for cardiovascular disease. According to a 2019 World Health Organization report, an estimated 1.13 billion people worldwide have raised blood pressure (BP) representing 7.5 million deaths and 12.8% of the total mortality.1, 2 This prevalence doubled compared to the rate reported globally in 1975, which was nearly 600 million2 The majority of cases are found in low- and middle-income countries that face the double burden of infectious and chronic diseases.2 Vietnam, a middle-income country, faces a “double burden” of communicable and non-communicable diseases, including hypertension. The prevalence of hypertension increased by 8% from 2002 to 2008, posing a massive health problem in Vietnam.3 In 2012, it was estimated that approximately 25.0% of Vietnamese adults aged 25 and above had been diagnosed with hypertension, and the prevalence among urban citizens was more than twice that of those living in rural areas.4, 5 These prevalences increase sharply for both sexes in those above 40 years of age.5

Modifiable risk factors of hypertension include tobacco use and the harmful use of alcohol, excess sodium intake, physical inactivity, and high body mass index. Knowledge of hypertension and its risk factors are stressed as an important aspect of improving healthy behaviors and guided behavior change in various models.6 A previous finding also indicated that a strong association was found between hypertension knowledge and a higher frequency of BP measurement.7 Participants may be more aware of their risk and may try to control it through daily habits such as reducing salt intake, regular physical activities, and stop/limit tobacco-use and alcohol consumption.7 Thus, inadequate rates of hypertension knowledge throughout the world emphasize the need for community-based interventions to reach more people and improve their awareness and knowledge of hypertension.8, 9, 10, 11

To reduce the hypertension burden in Vietnam, the National Strategy on Prevention and Control of NCDs (2015-2025) prioritizes lowering the rate of uncontrolled hypertension to less than 30% in 2025.12 At the same time, to support this strategy, the Vietnam Ministry of Health established national standards and guidelines for hypertension management. The Communities for Healthy Hearts program, funded by the Novartis Foundation and implemented by PATH in Ho Chi Minh City (HCMC), Vietnam was a well-timed program. The Communities for Healthy Hearts program was established in 2016, it drew on international best practices, and was built upon local innovations in developing, testing, and incubating novel models of hypertension service delivery that could strengthen primary health care options, bring services closer to home for people at risk or affected by hypertension, and engage multiple sectors in an effort to both increase access and affordability without burdening the public health system. A variety of awareness campaigns were introduced to reach the public including street-side banners, mobile loudspeaker broadcasts (a traditional and culturally appropriate mode of communication), leaflets distributed by community collaborators and checkpoints, and a social media campaign in HCMC. Together with BP checks, face-to-face consultation was stated as the most effective communication channel. For those with hypertension, they received an SMS reminder weekly that focuses on the importance of taking hypertension medication every day as prescribed medication adherence, medical appointment retention, or modifiable behavior change; and the many benefits of physical activity, limiting salt intake, and eating fruits and vegetables (Supplementary Data 1). These campaigns reached approximately 1,287,520 people at risk of hypertension.

To know the changes after the Communities for Healthy Hearts program implemented, an independent monitoring and evaluation project was put in place. This paper reports on an endline evaluation of community surveys after a 3-year implementation (from 2016 to 2019). It aimed to describe the changes in knowledge of hypertension among adults aged 40 and above in HCMC at the completion of the Communities for Healthy Hearts program as compared to the baseline survey's data. The resulting analysis provides insights that illustrate the changes after the Communities for Healthy Hearts program developed to increase the community's knowledge of hypertension and hypertension services.

Using the sampling method described above, we interviewed 2,592 participants, equally divided into baseline and endline surveys. Demographic characteristics are presented in Table 1.

Table 1
Participants' characteristics at baseline and endline surveys

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Table 1 shows the participants' characteristics at baseline and endline surveys. A similar pattern was observed in baseline and endline surveys. Most of the participants had only secondary school or lower education level, were self-employed, retired, or currently unemployed, and almost all were married or living with a partner. Approximately half of the participants had a normal BMI with a mean of 22.5 ± 3.1 at baseline survey and 23.0 ± 3.0 at the endline. While there was a considerable variation in the household income in the endline survey, nearly two-thirds of the respondents reported less than five million VND per month in the baseline (equal to less than the US$ 215.3). Additionally, the age- and sex-standardized hypertension prevalence were 33.7% and 41.6% for the baseline and endline evaluation, respectively.

Table 2 presents the knowledge of hypertension among all respondents. The number of respondents who correctly identified a normal BP increased from one half to nearly two-thirds between baseline and endline surveys. Whereas, the number of those who correctly identified at least three risk factors of hypertension increased nearly double from 44.9% in baseline to 91.7% in the endline survey. A high sodium diet was cited by most of the participants in both surveys. While the knowledge of the influence of inactivity and a stressful lifestyle on hypertension was extremely low in the baseline survey, it sharply increased in the endline measurement. When it comes to identifying at least three hypertension symptoms, the endline results were three times higher compared to baseline (from 27.4% to 85.5%).

Table 2
Knowledge of threshold and risk factors of hypertension

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The outcomes of the multivariate analysis of the factors associated with the knowledge of hypertension among respondents in the baseline and endline evaluation are shown in Table 3. The pattern was quite similar between the two evaluations. Overall, we identified that having higher educational level (adjusted odds ration [aOR], 2.22 and aOR, 2.08 in baseline and endline survey, respectively, for those had secondary school attainment; and aOR, 3.91 and aOR, 3.36 in baseline and endline survey, respectively, for those had high school or above attainment) and suffering from hypertension (aOR, 2.21 and aOR, 1.85 in baseline and endline survey, respectively) were positively associated with a higher knowledge of hypertension in both round evaluations. Whereas, compared to those who worked in the formal office, those were retired or unemployed had a lower knowledge level of hypertension (aOR, 0.53; 95% confidence interval, 0.32–0.90) in the baseline survey.

Table 3
Multivariate logistic analysis for hypertension knowledge in the baseline and endline evaluation

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Table 4 presents participants' accessibility and their information source preference related to hypertension messaging. Overall, 38.8% of participants had heard/seen/received information about hypertension in the baseline survey, and this number increased to 43.2% in the endline round. Regarding information sources, TV still remained the key informative channel. However, in the endline survey, health care professionals and the program's related channels (SMS message and collaborators) were reported as having provided hypertension information to the public.

Table 4
Accessibility and preference for the source of information related to hypertension in the last six months

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This study describes the changes in hypertension knowledge among adults aged 40 and above in four districts of HCMC after the implementation of the Communities for Healthy Hearts program. Overall, hypertension knowledge improved from baseline to endline evaluations including the normal BP range, hypertension risk factors, and its symptoms. Additionally, those who had higher educational levels, and experienced hypertension had higher levels of hypertension knowledge. Whereas, in the baseline round, the knowledge was poorer in those who were retired or unemployed, especially compared to government and non-government officers/staffs (Table 3).

The in-depth knowledge of hypertension was low in the baseline survey but increased in the endline, which sheds a light on the changes after the Communities for Healthy Hearts program implemented. The knowledge about the BP threshold was found to increase by nearly 15% between the two evaluations, standing at around two-thirds of the those surveyed in the endline survey. This percentage was also higher than findings in a rural population in China,16, 17 Tibet,18 and other Southeast Asian nations.11, 19 This difference may be explained by the difference in the data collection location and time. Respondents in HCMC, a metropolitan city in southern Vietnam, could have higher education levels and consequently a higher chance of getting more information on hypertension than those living in rural areas. The difference in knowledge of the normal range of BP level and study location was also shown in the previous study in Tibet where the sample was divided into resident areas.18

The likelihood of identifying a least three modifiable risk factors doubled from the baseline to the endline survey. Commonly cited risk factors included a high-sodium diet, excessive use of alcohol, and obesity; alcohol intake in both rounds was in line with previous findings in Vietnam5 and other parts of the world.16, 18, 20, 21 The number of people able to identify three or more hypertension symptoms were three times higher in the endline survey than the baseline survey, emphasizing the favorable changes of the Communities for Healthy Hearts program. Of these identified symptoms, the headache was cited as one of the common symptoms and that was consistent with previous findings.22, 23

Besides, factors associated with hypertension knowledge included maximum education level - the higher educational level someone attained, the better knowledge of hypertension they had. This finding is similar to other findings around the world.9, 10, 11 Participants previously diagnosed with hypertension had a greater amount of knowledge of hypertension, which is in line with a study in India.10 It could be explained by the fact that these people had greater health-seeking behaviors and implement preventive measures such as limiting tobacco and alcohol consumption, reducing salt intake, or doing regular exercise. They may previously have had medical appointments, frequently access health care services, and receive advice from health care professionals. On the other hand, hypertension knowledge was significantly lower among retirers/unemployed workers (applied even among those who had previously been diagnosed with hypertension). This had been attributed to the difference in education levels, lack of information access, and lesser likelihood to utilize health care services. Therefore, this study may serve as a guideline for promoting educational campaigns that are targeted to these subsections of the community.

In terms of receiving information about hypertension, more than two-fifths of participants had heard/received information during the last six months in the endline evaluation. In line with the national survey of hypertension in Vietnam and other nations, mass media, particularly television, was the main channel of obtaining hypertension information for participants in the surveys.5, 9 Almost all Vietnamese people had accessed to some type of mass media channels daily ay, which can provide information and improve their basic knowledge, such as the impact of high salt intake, tobacco smoking, and the harmful use of alcohol.24 Mass media channels should be taken into account for increasing and further spreading hypertension knowledge to the wider public.

With specialized knowledge, healthcare professionals usually are reliable sources for both receiving information and hypertension services.9 Improving and strengthening the knowledge of health care workers, at the primary care level and in community outposts, is needed for them to take further responsibility in hypertension prevention and management and reduce the health burden at higher levels of the healthcare system, will be critical for the long term management of chronic diseases like hypertension. In the endline measurement, the impact of the programs' channel was clearly seen since a number of respondents cited these channels as their informative sources (SMS message or collaborators). These findings are supportive evidence of the favorable changes after the implementation of the Communities for Healthy Hearts program.

This is one of the very first comprehensive, community-based hypertension interventions in Vietnam. With a relatively large sample size and employment of a clustered random sampling method, our findings have the potential to be generalized across urban Vietnam. Participants in the endline survey were more exposed to educational information throughout the Communities for Healthy Hearts program and therefore tended to have more knowledge about hypertension. On the other hand, there are some limitations to be acknowledged. We must note the possibility of other projects with interventions related to hypertension in HCMC (e.g. Abundant health program) that may have had an impact on the people's knowledge of NCDs. Further, this study only focuses on the change in hypertension knowledge and prevalence, not on the control rate and their behavior over time. Also, data was employed in a cross-sectional study, so it beyond the present scope to determine any causal relationship. This series cross-sectional studies were employed participants in the baseline and endline separately and had not followed them by time. Therefore, we could not make any further advanced analysis including difference-in-difference analysis.

For all the aforementioned reasons, our findings have several implications for forthcoming researches. The Communities for Healthy Hearts program improved the knowledge of normal range BP and was coupled with a relatively high level of knowledge on risk factors of hypertension and its symptoms for those surveyed in the endline of this evaluation. It has notable implications for future educational campaigns if it is to have further impact in similar studies. These campaigns should ensure even more targeted approaches for those who have lower educational levels and those who work as farmers or laborers. Besides Television, healthcare workers were the most frequently accessed source of information for the Vietnamese public.

In conclusion, the Communities for Healthy Hearts program improved the knowledge of hypertension among people in the areas of the intervention, particularly on its risk factors and symptoms. These findings shed light on the importance of comprehensive community-based hypertension management programs to improve prevention efforts through educational campaigns in Vietnam. Given the results, it highlights remaining gaps between different demographics and highlights the need for targeted approaches in several specific subgroups of the population in order to increase the knowledge levels of hypertension and its risk factors. These findings have the potential to inform research uptake, as well as provide guidance to similarly-designed interventions in Vietnam.

Supplementary Data 1

CH2 project overview.

Supplementary Data 2

Questionnaire.