Abstract
BACKGROUND: Uncontrolled hypertension is a major public health challenge in low- and middle-income countries. The Hypertension Control Program in Argentina (HCPIA) showed that a community health worker-led multicomponent intervention was effective for blood pressure (BP) reduction in resource-limited settings, but whether the intervention was equally effective across participant subgroups is unknown. OBJECTIVE: To identify participants who benefit the most from the HCPIA BP control intervention. METHODS: This secondary analysis used data from HCPIA, a successful 18-month cluster-randomized trial in 18 health centers with 1,432 low-income hypertensive patients in Argentina. Fifteen baseline characteristics were used to define subgroups. The proportion of controlled BP (<140/90 mmHg) was estimated using generalized linear mixed models with arm-by-subgroup interaction terms. The distribution of trial BP response among intervention patient subgroups was assessed. RESULTS: Participants were 53.0% female, a mean age of 56 years, and 17.4% controlled BP at baseline. After the intervention, 72.9% of intervention and 52.2% of control participants had controlled BP. The intervention was more effective in physically inactive patients (OR = 2.76, 95% CI: 1.82 and 4.21; p for interaction = 0.04), moderately active patients (OR = 3.08, 95% CI: 1.90 and 4.99; p for interaction = 0.03), and those with uncontrolled BP at baseline (OR = 2.77, 95% CI: 2.15 and 3.57; p for interaction = 0.05). Among intervention participants, 20.2% had no BP response (BP change < -4 mmHg), 41.3% had a moderate BP response (BP change: -4 mmHg to -24 mmHg), and 38.5% had a high BP response (BP change > -24 mmHg). Women (p=0.01), those who were physically inactive (p=0.03), and those not taking antihypertensive medications at baseline (p=0.001) had the greatest BP response. CONCLUSION: The effect of the intervention was consistent across many subgroups with some key groups showing a particularly strong intervention effect. These findings could be useful for planning future hypertension control programs in low- and middle-income countries.