Body fluid distribution in elderly subjects with congestive heart failure

The aims of this study were to investigate body fluid changes in elderly patients suffering from congestive heart failure (CHF) and to identify the fluid measurement that best characterizes fluid overload states in CHF patients by comparison with normal hydration in the elderly. In a case-controlled experimental design, 72 elderly subjects (65-98 yr), 38 healthy and 34 with CHF, were studied. Total body water (TBW) and extracellular water (ECW) were determined by dilution methods; fat-free mass (FFM) and fat mass (FM) were determined by dual-energy X-ray absorptiometry (DEXA). In healthy subjects, the FFM hydration expressed as TBW% FFM (males 72.0 +/- 4.3 vs females 72.4 +/- 5.0%) and ECW% TBW (males 47.3 +/- 3.4 vs females 47.8 +/- 5.1) were similar in both genders. ECW in liters for FFM and for TBW (ECW% TBW), corrected for body weight, was greater in the group with CHF than in the control group, in both sexes. Among the relative fluid measures, only ECW% TBW [odds ratio (OR) 1.5] independently predicted fluid retention. Having an ECW% TBW greater than 50% corresponded to an OR of about 10. In conclusion, elderly patients suffering from CHF have a characteristic increase in body fluid levels, mainly affecting the extracellular compartment, and ECW% TBW is a useful indicator of fluid retention.