Sustainability of a 12-month lifestyle intervention delivered by community health workers in reducing blood pressure in Nepal: 5-year follow-up of the COBIN open-label, cluster randomised trial

Background The sustainability and scalability of limited-duration interventions in low-income and middle-income countries remain unclear. We aimed to investigate the sustainability in reduction of blood pressure through a 12-month lifestyle intervention led by community health workers to reduce blood pressure in Nepal, 4 years after the intervention ceased. Methods The Community-Based Intervention for Control of Hypertension in Nepal (COBIN) trial was a non-blinded, cluster-randomised trial done in Kaski, Nepal. Adults aged 25-65 years were eligible. People were excluded if they declined consent, were severely ill, unlikely to be in the community throughout the intervention, or pregnant. During the 12-month intervention, female community health volunteers (FCHVs) visited participants in the intervention groups and provided lifestyle counselling and blood pressure measurement every 4 months. At the end of the 12-month intervention, systolic blood pressure was significantly lower in the intervention group than in the usual care group in all cohorts, ranging from -2 center dot 3 mm Hg (95% CI -3 center dot 8 to -0 center dot 8) lower in those with normal blood pressure to -4 center dot 9 mm Hg (-7 center dot 8 to -2 center dot 0) in the hypertensive cohort. The primary outcome for this follow-up study was a mean change in systolic blood pressure from baseline to follow-up at 60 months. We did an intention- to-treat analysis. Findings Between April 1, 2015, and Dec 31, 2015, 1638 participants were recruited in COBIN (939 [57 center dot 3%] assigned to intervention and 699 [42 center dot 7%] assigned to usual care). Of the 1468 (89 center dot 6%) who completed the 12-month assessments, we followed up 1352 (92 center dot 1%) participants at 60 months, between Oct 11, 2020, and May 5, 2022. 964 (71 center dot 3%) participants were women and 388 (28 center dot 7%) were men. From baseline to 60 months, the mean systolic blood pressure increased by 10 center dot 4 mm Hg (95% CI 9 center dot 1-11 center dot 6) in the intervention group and 6 center dot 0 mm Hg (4 center dot 6-7 center dot 5) in the usual care group (adjusted mean difference 4 center dot 1 mm Hg [2 center dot 2 to 5 center dot 8]). Interpretation Lifestyle counselling and blood pressure monitoring by community health workers is effective in substantially reducing blood pressure while adults are being monitored in a trial but, following cessation of the intervention, this benefit is not maintained in the long term, with potential for harm. This finding could have important implications for funders and research communities to regularly target participants for education and follow-up at an optimal timepoint to reduce any likelihood of harm. Copyright (c) 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.