Risk factor paradox in hemodialysis: Better nutrition as a partial explanation

The higher mortality rate in patients on hemodialysis is primarily due to t he higher rate of cardiovascular disease. Yet, paradoxically, overweight, h ypertension, and hyperlipidemia, which are cardiovascular risk factors in t he general population, have been reported to correlate with better patient survival in hemodialysis. To examine whether this "risk factor paradox" in hemodialysis is due to the positive influence of accompanying better nutrit ion, we prospectively obtained data on fasting lipids, biochemical markers of nutrition, body mass index (BMI), and blood pressure (BP) in 453 hemodia lysis patients and related them to 1 year mortality. As previously noted, b ody weight, blood pressure, and certain serum lipids positively correlated with survival. Serum prealbumin, one of the most sensitive and specific bio chemical markers for nutrition, correlated positively with hypercholesterol emia (r = 0.30, p < 0.001) and BMI (r = 0.12, p < 0.02), but not with mean arterial pressure (MAP) (r = 0.01, p = NS). By analysis of variance, patien ts in the upper tertile (i.e., higher levels) of BMI and cholesterol but no t MAP had significantly higher serum prealbumin and creatinine compared wit h those in the lower tertile. Our data lend support to the hypothesis that, in patients on hemodialysis, the positive effect of higher BMI and hyperli pidemia but not of high BP could be partially explained on the basis of the accompanying better nutrition. Although not proven, correcting risk factor s while improving nutrition may offer better outcomes for patients on dialy sis.