Background: Elements of malnutrition-inflammation complex syndrome (MICS) may blunt the responsiveness of anemia of end-stage renal disease (ESRD) to recombinant human erythropoietin (EPO).
Methods: The authors examined cross-sectional associations between the required dose of EPO within a 13-week interval as prescribed by practicing nephrologists who were blind to the study and several laboratory values known to be related to nutrition and/or inflammation, as well as the malnutrition-inflammation score (MIS), which is a fully quantitative assessment tool based on the subjective global assessment of nutrition.
Results: A total of 339 maintenance hemodialysis (MHD) outpatients, including 181 men, who were aged 54.7 +/- 14.5 years (mean +/- SD), who had undergone dialysis for 36.3 +/- 33.2 months, were selected randomly from 7 DaVita dialysis units in Los Angeles South/East Bay area. The average weekly dose of administered recombinant human EPO within a 13-week interval was 217 +/- 187 U/kg. Patients were receiving intravenous iron supplementation (iron gluconate or dextran) averaging 39.5 +/- 47.5 mg/wk. The MIS and serum concentrations of high-sensitivity C-reactive protein, interleukin 6 (IL-6), tumor necrosis factor-alpha, and lactate dehydrogenase had positive correlation with required EPO dose and EPO responsiveness index (EPO divided by hemoglobin), whereas serum total iron binding capacity (TIBC), prealbumin and total cholesterol, as well as blood lymphocyte count had statistically significant but negative correlations with indices of refractory anemia. Most correlations remained significant even after multivariate adjustment for case-mix and anemia factors and other relevant covariates. Similar associations were noticed across EPO per body weight tertiles via analysis of variance and after estimating odds ratio for higher versus lower tertile via logistic regression after same case-mix adjustment.
Conclusion: The existence of elements of MICS as indicated by a high MIS and increased levels of proinflammatory cytokines such as IL-6 as well as decreased nutritional values such as low serum concentrations of total cholesterol, prealbumin, and TIBC correlates with EPO hyporesponsiveness in MHD patients.