Hypervolemia is associated with increased mortality among hemodialysis patients

摘要

Among chronic hemodialysis patients, 217 hospitalizations/1000 patient-years are due to congestive heart failure; some are attributable to unrecognized hypervolemia. Hypervolemia can be detected by relative plasma volume (RPV) monitoring. The purpose of this study was to examine among 308 patients on long-term hemodialysis the value of slope of RPV compared to either ultrafiltration volume or ultrafiltration rate index in determining all-cause mortality. RPV slopes were calculated by least-squares regression. These slopes were related to all-cause mortality in unadjusted and adjusted Cox proportional hazards models. Over a median follow up of 30 months (IQR 14 – 54 months) 96 (31%) patients died yielding a crude mortality rate of 113/1000 patient years. We found that 1) RPV slope measurements were of prognostic significance (hazard ratio of flatter slopes (>1.39%/hour) 1.72, p = 0.01); 2) the ultrafiltration volume alone was not prognostically informative (hazard ratio of higher UF volume (>2.7 liter/dialysis) 0.78, p=0.23); 3) the ultrafiltration rate index alone was also not prognostically informative (hazard ratio of higher UF rate index (>8.4 mL/kg/hr) 0.89, p=0.6); and 4) the prognostic relationship of RPV slope to mortality was independent of conventional and unconventional cardiovascular risk factors including the ultrafiltration volume, ultrafiltration rate or ultrafiltration volume/kg post weight. RPV monitoring yields information that is prognostically important and independent of several risk factors including ultrafiltration volume, aggressiveness of ultrafiltration, and interdialytic ambulatory BP. Its use to assess excess volume among chronic hemodialysis patients should be tested in randomized controlled trials.