Effects of lifestyle-related interventions on blood pressure in low and middle-income countries: Systematic review and meta-analysis

Despite the overwhelming evidence supporting the effectiveness of antihypertensive medication, hypertension remains poorly controlled in low and middle-income countries (LMICs). Lifestyle intervention studies reporting effects on blood pressure published from January 1977 to September 2012 were searched on various databases. From the 6211 references identified, 52 were included in the systematic review (12024 participants) and 43 were included in the meta-analysis (in total 6779 participants). We calculated and pooled effect sizes in mmHg with random-effects models. We grouped interventions into behavioral counseling (1831 participants), dietary modification (1831 participants), physical activity (1014 participants) and multiple interventions (2103 participants). Subgroup analysis and meta-regression were used to evaluate origins of heterogeneity. Lifestyle interventions significantly lowered blood pressure levels in LMIC populations, including in total 6779 participants. The changes achieved in SBP (95% confidence interval) were: behavioral counseling -5.4 (-10.7, -0.0)mmHg, for dietary modification -3.5 (-5.4, -1.5)mmHg, for physical activity -11.4 (-16.0, -6.7)mmHg and for multiple interventions -6.0 (-8.9, -3.3)mmHg. The heterogeneity was high across studies and the quality was generally low. Subgroup analyses showed smaller samples reporting larger effect sizes; intervention lasting less than 6 months showed larger effect sizes and intention-to-treat analysis showed smaller effect sizes Lifestyle interventions may be of value in preventing and reducing blood pressure in LMICs. Nevertheless, the overall quality and sample size of the studies included were low. Improvements in the size and quality of studies evaluating lifestyle interventions are required.