Does home-based screening improve hypertension diagnosis, treatment and control? A regression discontinuity analysis in urban India

As part of India's efforts to expand primary healthcare services, several state governments are implementing or considering home-based hypertension screening programmes to improve population-wide diagnosis and blood pressure (BP) control rates. However, there is limited evidence on the effectiveness of home-based screening programmes in India. Using six waves of population-representative cohort data (N=15574), we estimate the causal effect of a home-based hypertension screening intervention on diagnosis, treatment, and BP using a novel application of the Regression Discontinuity Design. We find that measuring individuals' BP in their homes and providing health information and a referral to those with elevated BP did not meaningfully improve hypertension diagnosis (0.12 percentage points (pp), 95% CI -1.39 to 1.75), treatment (-0.16 pp, 95% CI -2.18 to 1.03), or change in BP (systolic: -0.96mm Hg, 95% CI -5.63 to 1.14; diastolic: 0.21, 95% CI -1.65 to 1.65). Our heterogeneity analyses suggest that home-based screening may reduce systolic BP for women with secondary education and women living in Chennai. However, we find null effects for diagnosis and treatment among these subpopulations and in all outcome variables across the other subpopulations and alternative specifications. Our findings suggest that a lack of knowledge of one's hypertension status might not be the primary reason for low diagnosis and treatment rates in India, where other structural and behavioural barriers may be more relevant. Adapting screening efforts to address these additional barriers will be essential for India's efforts to achieve universal health coverage.