Influence of excess weight on mortality and hospital stay in 1346 hemodialysis patients

Background. Body mass index (BMI) at its extremes contributes to morbidity and mortality in the general population. Its influence on morbidity and mor tality in patients on hemodialysis is not clearly defined. Methods. The BMI in 1346 patients attending limited-care hemodialysis units across the stale of Mississippi was determined, and its relation to one-ye ar mortality and hospital stay was assessed using the Cox proportional haza rd model. Results. Of these patients, 89% were black, and 11% were white. Thirty-eigh t percent of patients were overweight (BMI > 27.5), and 13% were underweigh t (BMI < 20). The highest (27.60 +/- 0.29, mean +/- se) and the lowest (24. 54 +/- 0.48) BMI were noted in black females and white males, respectively. BMI, race, hematocrit (Hct), and biochemical markers of better nutrition p ositively influenced the survival, whereas age, serum globulin, and diabete s had a negative influence. In a Cox multivariate analysis, BMI, age, diabe tes, prealbumin, and creatinine, but not race, serum albumin, Hct, or serum globulin, retained significant influence on survival. Compared with the no rmal weight (BMT between 20 and 27.5), the one-year survival rate was signi ficantly higher in the overweight patients and lower in the underweight pat ients. With a one-unit increase in BMI over 27.5, the relative risk for dyi ng was reduced by 30% (P < 0.04), and with a one-unit decrease in BMI below 20, the relative risk was increased by 1.6-fold (P < 0.01). Furthermore, u nderweight patients had significantly lower levels of biochemical markers o f nutrition and higher frequency and longer duration of hospital stay. Conclusion. Adequate dialysis with special attention to proper nutrition ai med to achieve the high end of normal BMI may help to reduce the high morta lity and morbidity in hemodialysis patients.