Depression increases the risk of hypertension incidence: a meta-analysis of prospective cohort studies

Background: It has long been known that depression is associated with hypertension but whether depression is a risk factor for hypertension incidence is still inconclusive. Objectives: To assess whether depression increases the incidence of hypertension. Method: Literatures were searched from PubMed, EMBASE, Cochrane and PsycINFO without language restrictions. Any prospective cohort study was included, which reported the correlation between depression and incidence of hypertension in apparently healthy normotensive individuals. At baseline, the studies which had at least one self-report or interview-based assessment on depressive symptoms/disorders were selected. The definition of hypertension was defined as a repeatedly elevated blood pressure exceeding 140 (systolic) and/or over 90mmHg (diastolic) determined in interview, use of antihypertensive medications, or self-reported or recorded diagnosed hypertension. Studies with cross-sectional or case-control design were excluded. Data abstraction was conducted independently by two authors. Results: Seventy-five full texts were initially searched, but only nine studies met our inclusion criteria, and they were comprised of 22 367 participants with a mean follow-up period of 9.6 years. We found that depression increased the risk of hypertension incidence [adjusted relative risk 1.42, 95% confidence interval (CI) 1.09 to 1.86, P=0.009] and the risk was significantly correlated with the length of follow-up (P=0.0002) and the prevalence of depression at baseline (P < 0.0001). Conclusions: Our meta-analysis supports that depression is probably an independent risk factor of hypertension. It is important to take depression into consideration during the process of prevention and treatment of hypertension. Further studies are needed to exclude the effects of other confounding factors.