Association of hyperhydration evaluated by bioelectrical impedance analysis and mortality in patients with different medical conditions: Systematic review and meta-analyses

Summary Background and aims Fluid retention is a risk factor for mortality in several medical conditions. However, the accurate and fast assessment of hydration status remains a challenge in the clinical practice. Bioelectrical impedance analysis (BIA) could be an alternative to assess volume status. This systematic review aimed to evaluate the use of BIA to identify hydration status in patients with different medical conditions and to verify the association of hyperhydration, assessed by BIA, with mortality. Methods This systematic review and meta-analyses included 29 studies conducted from 2002 to 2017 among different medical conditions in adults. Eligible studies were randomized and non-randomized clinical trials, prospective and retrospective observational studies. For quality assessment of studies, Effective Public Health Practice Project (EPHPP) was used. Results Twelve studies provided data eligible for meta-analyses. A direct association between hyperhydration and mortality was observed (Odds Ratio [OR] 4.38; Confidence interval 95% [95% CI] 2.76–6.94), even when stratified for medical condition (OR 4.37; 95% CI 1.15–6.92) and BIA device (OR 4.37; 95% CI 2.75–6.92). Conclusion Hyperhydration, evaluated by BIA, was positive associated with mortality. Therefore, the prognostic impact of hyperhydration may be properly assessed by a bedside tool such as BIA.