Socioeconomic Inequalities in Hypertension in Kenya: A Decomposition Analysis of 2015 Kenya STEPwise Survey on Non-communicable Diseases Risk Factors

Abstract

IntroductionOne in four Kenyans have raised blood pressure. Despite this high prevalence of hypertension and known association between socioeconomic status and hypertension, there is a paucity of evidence on inequality in raised blood pressure in Kenya. Hence, we quantified the socioeconomic inequality in hypertension in Kenya and decomposed the determinants contributing to such inequality.MethodsWe used data from the 2015 Kenya STEP wise survey for non-communicable diseases risk factors. We included 4,398 respondents aged 18–69 years. We estimated the socioeconomic inequality using the concentration index (C) and decomposed the C using Wag staff decomposition analysis.ResultsThe overall concentration index of hypertension in Kenya was − 0.08 (95% CI: −0.14, − 0.02; p = 0.007), showing socioeconomic inequalities in hypertension disfavouring the poor population. Half (52.8%) of the pro-rich inequalities in hypertension was explained by body mass index (52.8%) while 21.1% by socioeconomic factors (paid employment (9.3%), education (7.7%) and poorest wealth quintile (4.1%)) and 17.6% by demographic factors (female gender (11.8%), age (5.2%) and marital status (0.6%)). Regional differences explained 8.1% of the estimated inequality with the Central region alone explaining 6.9% of the observed inequality. Our model explained 98.3% of the estimated socioeconomic inequality in hypertension in Kenya with a small non-explained part of the inequality (− 0.001).ConclusionThe present study shows substantial socioeconomic inequalities in hypertension in Kenya, mainly explained by metabolic risk factors (body mass index), individual health behaviours, and socioeconomic factors. Kenya needs gender- and equity-focused interventions to curb the rising burden of hypertension and inequalities in hypertension.