Orthostatic hypotension and mortality risk: a meta-analysis of cohort studies

Context Orthostatic hypotension (OH) has been found to be related to increased risk of mortality, although results of previous cohort studies were not always consistent. Objective The aim of this meta-analysis was to investigate the association between OH and mortality risk. Data source Medline, Embase and references cited in related reviews and studies. Study selection Cohort studies evaluating the association between OH and mortality risk were identified. Data extraction Two investigators read all papers and extracted all relevant information. Results A total of 56125 subjects with 11580 mortality cases from nine cohorts were included in the meta-analysis. Pooled results indicated that the presence of OH at baseline was significantly associated with an increased risk of all-cause mortality (adjusted risk ratio (RR)=1.40, p<0.001). Subgroup analysis suggested that the association between OH and all-cause mortality was less strong for the studies in which classic risk factors were adequately adjusted compared with those in which they were not adequately controlled. In addition, although our meta-analysis failed to reveal a significant association between OH and cardiovascular (CV) mortality (RR=1.20, p=0.47), we did find that subjects with OH had an increased risk of non-CV mortality (RR=1.18, p=0.05). Conclusions The presence of OH is associated with a significantly increased risk of all-cause mortality, which may partially be mediated by classic risk factors. Further research is needed to determine whether the association between OH and mortality risk is causal.