Primary Care Strategies to Reduce High Blood Pressure: A Cluster Randomized Trial in Rural Bangladesh, Pakistan and Sri Lanka Cardiovascular diseases (CVD) have become the leading cause of mortality globally. In South Asia, high rates of CVD are observed at a younger age than in other countries causing a reduction in productive life years with severe economic consequences. High blood pressure (BP) confers the greatest attributable risk to death and disability associated with CVD.  Our Wellcome Trust funded Control of Blood Pressure and Risk Attenuation (COBRA) trial (2004 to 2007) in Karachi, Pakistan, suggested the combined strategy of family based home health education (HHE) delivered by trained community health workers (CHW) plus care of individuals by trained private general practitioners (GP) to optimally manage hypertension had the most marked beneficial impact on BP compared to usual care, or single interventions. However, the COBRA intervention was designed for an urban South Asian setting, where private GPs cater to over 75% of the patients seeking care. Most of South Asia is still rural (73% Bangladesh, 64% Pakistan, 71% India, 85% Sri Lanka) where prevalence of hypertension is high and healthcare infrastructure and provider characteristics are very different compared to the urban setting. The COBRA trial did not evaluate effectiveness of strategies delivered using the public health infrastructure, or generalizability to the rural population in Pakistan. It is also not clear whether any benefit would extend to rural communities in other South Asian countries.  In our ongoing COBRA-BPS feasibility study in Bangladesh, Pakistan, and Sri Lanka, we modified COBRA by developing a comprehensive "multicomponent intervention (MCI)" for effective delivery of hypertension care using the rural predominantly public primary care infrastructure. We also conducted extensive stakeholder consultation and received very favourable response for a full scale trial to evaluate MCI in 3 countries.  We now propose a cluster randomised controlled trial (RCT) on 2550 adults with hypertension in 30 rural communities in Bangladesh, Pakistan and Sri Lanka, to evaluate a comprehensive MCI comprised of specifically comprised 1) home health education (HHE) by government community health workers (CHWs),  2) blood pressure (BP) monitoring and stepped-up referral to a trained general practitioner (GP) using a checklist,  3) trained public and private providers in management of hypertension and using a checklist,  4) designated hypertension triage counter and hypertension care coordinators in government clinics,  5) a financing model to compensate for additional health services including targeted subsidies.    A total of 15 communities (5 in each country) will be randomised to MCI and 15 (5 in each country) to usual care in 3 countries. Individuals with hypertension will be followed for 2 years to assess whether MCI compared to usual care is more effective at lowering BP, and cost effective in terms of preventing CVD related disability and death. We will also interview stakeholders and conduct serial focus group discussions of patients on their experience with the strategy in relation to various components of MCI.  If shown to be successful, our findings will be helpful in securing political commitment from stakeholders for up-scaling MCI strategies at the national level in these South Asian countries. The South-South collaboration and shared experiences will be very valuable in co-ordinating a regional action plan on NCDs with a focus on hypertension as an entry point. Our trial will provide direct evidence of the value of using comparable models and platforms for non-communicable disease management which would extend to other Asian countries with similar ethnic population and healthcare infrastructure. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.