Population Based Strategies for Effective Control of High Blood Pressure in Pakistan

Studies have established that high blood pressure (BP) is the most common risk factor for cardiovascular disease (CVD). Despite a heavy burden of hypertension (33% of all persons aged 45 years and over), there are no reliable data on comparative strategies to manage hypertension in Pakistan. Our Wellcome Trust funded pilot study in Karachi, Pakistan on 320 adults aged 40 years and over showed that the prevalence of hypertension (95% CI) was 40.3% (34.9-45.7%), and CVD was 32.5% (27.6-37.8%).

We will now conduct a study with two components: 1) cross sectional study to determine the prevalence of CVD, and its determinants in Karachi, Pakistan; and 2) prospective, 2x2 factorial design, cluster allocation intervention study to evaluate the impact of a i) Population approach of household health education (HHE) by community health workers (CHW) on BP levels of population aged 5 years or over in low-middle income communities of Karachi; and ii) High-Risk approach of special BP management administered by intensively trained local general practitioners on BP levels of hypertensive subjects aged > = 40 years from the above population.

The cost effective BP control strategy would serve as a model for a much-needed national level hypertension control programme in Pakistan, and possibly other developing countries in South Asia.

We hypothesize that 1) HHE delivered by trained CHW is superior to no HHE in lowering BP levels of the population; and 2) management of hypertension by specially trained GPs is better than usual care provided in the communities of Karachi in lowering blood pressure of hypertensive subjects.

The proposed study will be conducted among the low and middle-income population in Karachi. This population is likely to be particularly prone to CVD, has the poorest access to quality care, and is often prescribed expensive drugs by GPs.

Screening visit: The Community Health Workers (CHW) will pay home visits to invite all subjects aged 5 years or over to participate in the survey. The screening would have three levels: 1) Household screening for subjects aged 5 years and over (n= 17,850 individuals, 3000 households). 2) Adult screening for individuals aged 40 years or over (n= 4200 individuals). 3) Hypertensive adults screening (n= 1860 individuals) for those identified to have hypertension on adult screening will be invited for re-measurement of BP to confirm hypertension.

Intervention Effectiveness Study: This is a 2x2 factorial design, cluster allocation intervention study comparing controls with intervention by primary care GP, with or without health education. The main comparisons relate to the reduction of BP in a) all household members (aged > 5 years), and b) hypertensive adults (aged > 40 years).

Interventions: The sample will be assigned to four intervention groups:

• Group A: Routine care.
• Group B: Routine care plus Health Education
• Group C: Care provided by trained GP
• Group D: Care provided by trained GP plus Health Education.