Inflammation and Inverse Associations of Body Mass Index and Serum Creatinine With Mortality in Hemodialysis Patients

Objective: Protein-energy wasting and inflammation are common and associated with an increased risk of mortality in hemodialysis (HD) patients. We examined the extent to which they mediate the associations of each other with death in this population. Study Design: Retrospective analysis of the Hemodialysis (HEMO) Study data. Setting: Prevalent HD patients. Participants: One-thousand HEMO study participants with data available on C-reactive protein (CRP), body mass index (BMI), and serum creatinine. Intervention: None. Main Outcome Measure: The associations of CRP, BMI, and serum creatinine with time to all-cause mortality separately and together in multivariate Cox models. Results: In 1,437 patient-years of follow-up, there were 265 (26.5%) all-cause deaths. Compared with the lowest CRP quartile, the highest quartile was associated with a hazard ratio (HR) of 2.02 (95% confidence interval [CI], 1.31-3.10) for all-cause mortality. This association of highest CRP quartile with mortality was not attenuated with further adjustment for BMI and serum creatinine (HR, 2.13; 95% CI, 1.38-3.30). When serum albumin was added to the model, the hazard of death associated with highest CRP quartile was modestly attenuated (HR, 1.88; 95% CI, 1.21-2.92). In contrast, both BMI (for each kg/m² increase; HR, 0.94; 95% CI, 0.91-0.96 for all-cause mortality) and serum creatinine (for each mg/dL increase; HR, 0.85; 95% CI, 0.79-0.90 for all-cause mortality) had strong, independent protective effects. Further adjustment with CRP had a negligible effect on these associations. Conclusion: The associations of markers of nutrition and inflammation with mortality are largely independent of each other in HD patients.