The prevalence and heterogeneity of prehypertension: a meta-analysis and meta-regression of published literature worldwide

OBJECTIVE Prehypertension appears to be a precursor of hypertension and has been recognised as a major risk factor for cardiovascular disease (CVD). Recognition of prehypertension provides important opportunities for preventing hypertension and CVD. We aimed to investigate the worldwide prevalence and heterogeneity of prehypertension. METHODS We performed a meta-analysis of cross-sectional studies worldwide that reported the prevalence of prehypertension. We searched for publications between January 1966 and November 2010, using PubMed, Ovid and the Cochrane Library, with the keyword 'prehypertension', supplemented by a manual search of references from recent reviews and relevant published original studies. Pooled prevalence of prehypertension was calculated using random-effects models. Heterogeneity was investigated by subgroup analysis and meta-regression. Twenty-two articles met our inclusion criteria, with a total sample of 242 322 individuals. RESULTS The overall pooled prevalence of prehypertension was 38%. Significant heterogeneity across estimates of prevalence was observed (p = 0.000, I(2) = 99.9%). The prevalence rose as the sample size increased, and was higher among men than women (41 vs 34%). The non-Asian population was more likely to be prehypertensive than Asian individuals (42 vs 36%). A high prevalence of 47% was observed among the black African population in the non-Asian subgroup. The inception year of the surveys was the only source of heterogeneity we found by meta-regressional analysis (p = 0.06). CONCLUSION These results indicate that the prevalence of prehypertension was relatively high, particularly among males. Although more attention has been paid to this segment of the population since 2003, additional practical and reasonable steps should be taken to prevent and treat prehypertension.