Authors

1. Skar, Pal
2. Young, Lynne
3. Gordon, Carol

Abstract

Review question/objective: The objective of this review is to identify studies reporting on lay health worker- or volunteer-led community-based programs for blood pressure screening and cardiovascular awareness in order to determine if these programs contribute to changes in blood pressure among participants over time.

The specific question for this review is: What are the changes in blood pressure among adult users of community-based blood pressure screening and awareness programs operated by lay health workers or volunteers as measured by the differences in systolic and diastolic blood pressure between the user's first visit to the program and their last visit to the program?

Background: Cardiovascular diseases, such as stroke and heart disease, are quickly becoming global diseases manifesting in countries and communities where they traditionally had not been widespread. The World Health Organization (WHO) has reported that "in the Asia/Pacific region, [cardiovascular disease] has become increasingly prevalent in recent decades, and now accounts for about one third of all deaths".1^(p20) One risk factor that can lead to cardiovascular disease is hypertension. Based on WHO data from 2008, hypertension is now a global problem affecting 27% of the population 25 years of age or older.2

The risk for cardiovascular disease also appears to be higher among people in urban areas.3 A recent United Nations population report indicates that in the next 40 years we could see an increase in the world's population by 2.3 billion people.4 The majority of these people will be residing in urban areas, particularly in developing nations. Between 2011 and 2050, "the population living in urban areas is projected to gain 2.6 billion, passing from 3.6 billion in 2011 to 6.3 billion in 2050".5^(p1) Population growth in urban areas is therefore not only projected to include the expected population growth but also expected to include a shift of rural population to urban centers and "most of the population growth expected in urban areas will be concentrated in the cities and towns of the less developed regions".5^(p1) This growth of urban areas has the potential to put enormous pressures on health care systems that are already struggling to cope with the rapid increase in diseases thought to be more prevalent in Western societies, such as cardiovascular diseases.

Hypertension may be difficult to treat due to a number of factors. Globally, access to antihypertensive medications, hypertension screening, and access to medical care vary from one country to another.12 Lifestyle factors, such as salt and alcohol consumption, stress, smoking, body weight, and exercise, are risk factors for hypertension that may be influenced by culture, which can in turn support or hinder lifestyle decisions that could significantly affect blood pressure.1 Hypertension, however, is easy to detect. A trained person with access to a low-cost sphygmomanometer can detect abnormal blood pressures quickly; however, access to trained personnel is not universally guaranteed. Globally - according to one model of skilled health care worker density and total requirement offered for discussion by the Global Health Workforce Alliance and WHO12 - there could currently be an estimated shortage of over seven million skilled health care workers (midwifes, nurses and physicians), as measured against a theoretical density of skilled health care workers to population. The shortage of skilled health care workers in this model could grow to over 12 million by 203512 if the assumptions of the model and population growth estimates are valid. Through rapid urbanization5 the potential for inequities in access to healthcare is also increased.3

Over the last few years, a number of community-based blood pressure screening and education initiatives have been established.9 These initiatives have been created either as part of research,13 as part of community outreach programs by publicly funded agencies,16 or as part of an outreach by not-for-profit organizations with a particular interest in reducing cardiovascular disease in specific hard-to-reach populations.14,15 Several systematic reviews have been conducted to assess different models for delivering services to people living with high blood pressure6,7,19,20 to assess community-based programs with a focus on cardiovascular disease,8,9 and to assess effectiveness of community health workers (CHW) in a variety of settings.10 These systematic reviews point to the importance of distinguishing between different categories of health care providers, their training and their roles in program delivery when assessing studies for possible inclusion in a systematic review.

In a systematic review of studies from the US by Brownstein et al.8 focusing on the effectiveness of community health workers (CHWs) in the care of people with hypertension, this category of health care providers went under many different names. Community health workers in this review were defined as "any health workers who carried out functions related to health care deliver, were trained as part of an intervention, had no formal paraprofessional or professional designation, and had a relationship with the community being served".8^(p436) One of the findings from this review was the wide variety of formal training of the CHWs. In other parts of the world, a CHW might be defined differently. In their review of CHW-based programs focusing on children's health, Bhattacharyya, Winch, LeBan and Tien17 found that "in general CHWs are not paid salaries because the MOH (Ministry of Health) or donors do not consider salaries to be sustainable. Yet CHWs are often held accountable and supervised as if they were employees. Community health worker programs must recognize that CHWs are volunteers (emphasis in original), even if they receive small monetary or nonmonetary incentives. They are volunteering their time to serve the community".17^(pxii) One Canadian model for delivering a cardiovascular awareness program designed to reach older adults through their primary care provider is based on volunteers with basic training to perform blood pressure measurements and cardiovascular health information.13

In a global review of a wide range of public health and health promotion initiatives operated by lay health workers from 2005, Lewin et al.11 identified over 40 different names or terms for a lay health worker. However, the definition of a lay health worker used by Lewin et al. is very similar to the definition of CHWs offered by Brownstein et al.8 Lewin et al.'s systematic review was the only study with a global focus that was located that reviewed studies of programs with a cardiovascular component using lay health workers. In this study, the sample size of studies focusing on lay health workers and cardiovascular disease was small (N=3) and the results from two of the studies were inconclusive to the point where the authors felt they could not pool the results.11

While a lay health worker may or may not receive some compensation for their work, volunteers in higher income areas of the world such as in North America typically do not receive any compensation. Volunteers, as observed by Bhattacharyya et al.,17 are common in many parts of the world, and in some areas they provide delivery of programs and services that reach hundreds of thousands of individuals.18 One challenge for this systematic review will therefore be to isolate those programs that are delivered by lay health workers or volunteers who receive little or no compensation and programs where staff is paid. The importance of this distinction is on one hand related to cost - as observed by Bhattacharyya et al.,17 many organizations responsible for delivery of community-based programs do not have funding for salaried staff. On the other hand there might be other factors in the relationship between a community being served by a program and the staff delivering the program. One such factor could be linked to the role of the person delivering the program as either a paid health care professional or an unpaid lay health worker or volunteer.17

Through this proposed JBI systematic review, the reviewers will focus on community-based blood pressure screening and health information programs delivered by either lay health workers or volunteers. Previous systematic reviews6-9,19,20 have indicated that programs focusing on blood pressure reduction delivered in a variety of settings and delivered by a variety of health care professionals might lower blood pressure among program participants over time. This systematic review will be limited to community-based programs rather than hospital or research facility-based programs, and to programs delivered by lay health workers or volunteers rather than programs delivered by paid community health workers, nurses or teams of health care providers under direction of a primary care provider. Compared to other recent systematic reviews which focused on studies with comparison groups6,7 and included few studies where lay health workers were involved, this systematic review will attempt to fill this gap in knowledge about programs delivered by lay health workers or volunteers by focusing on non-randomized controlled studies which report blood pressure changes over time in programs targeting the general population. Community-based programs might have a variety of designs with a number of different interventions, and where possible these designs and interventions will be identified and subgroup analysis conducted as appropriate. It is hoped that this systematic review can extend the work by Lewin et al.11 by identifying additional studies globally, focusing on programs delivered by lay health workers or volunteers but limited to studies reporting changes in blood pressure over time. Where possible, a meta-analysis of the changes in blood pressure over time among participants in these programs will be conducted.

It is hoped that this proposed systematic review may assist those who fund and plan community-based blood pressure and health awareness initiatives by providing additional evidence for decision=making regarding which model for program delivery will provide the optimal solution given local circumstances, culture, goals and resources.

The Cochrane Database of Systematic Reviews, PROSPERO and the JBI Database of Systematic Reviews and Implementation Reports were searched for published systematic reviews or protocols on this topic with a global scope and a focus on lay health workers or volunteers. None were found with the exception of the study by Lewin et al.11 from 2005 as previously reported.