E. Fleischmann

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

The higher mortality rate in patients on hemodialysis is primarily due to the higher rate of cardiovascular disease. Yet, paradoxically, overweight, hypertension, and hyperlipidemia, which are cardiovascular risk factors in the 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 nutrition, we prospectively obtained data on fasting lipids, biochemical markers of nutrition, body mass index (BMI), and blood pressure (BP) in 453 hemodialysis patients and related them to 1 year mortality. As previously noted, body weight, blood pressure, and certain serum lipids positively correlated with survival. Serum prealbumin, one of the most sensitive and specific biochemical markers for nutrition, correlated positively with hypercholesterolemia (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, patients in the upper tertile (i.e., higher levels) of BMI and cholesterol but not MAP had significantly higher serum prealbumin and creatinine compared with those in the lower tertile. Our data lend support to the hypothesis that, in patients on hemodialysis, the positive effect of higher BMI and hyperlipidemia but not of high BP could be partially explained on the basis of the accompanying better nutrition. Although not proven, correcting risk factors while improving nutrition may offer better outcomes for patients on dialysis.

Anemia and iron target realization in 1998: Clinical management of anemia in 1,639 patients on hemodialysis

Anemia management in hemodialysis patients continues to evolve, and recently, greater emphasis has been placed on the wider use of intravenous iron to maintain adequate iron levels. This survey provides scarcely available yet potentially useful information on the clinical treatment of anemia in a large cohort of hemodialysis patients. The erythropoietin and iron administration details and pertinent laboratory measurements from 1,639 patients were analyzed for the month of December, 1998. A standardized protocol had been used in that erythropoietin was begun at a total weekly dose of 150 U/kg IV or 100 U/kg subcutaneously and was then adjusted to maintain a hematocrit (Hct) of 33–36%. Iron supplements, oral, IV, or both, were administered to maintain percent transferrin saturation (TSAT) at 20–30% and/or a serum ferritin of 100–500 ng/ml. No intravenous iron was administered if the ferritin was more than 500 ng/ml. Although 82% of patients were on iron supplementation and, among them, 58% were on IV iron, the percentage of patients with TSAT >20, i.e., bioavailable iron, was only 51%. The serum ferritin was high at 498 ± 10 ng/ml (mean ± SEM) and 88% and 10% of patients had serum ferritin >100 and >1,000 ng/ml, respectively, suggestive of sequestration of part of the infused iron. Erythropoietin was administered to 96% of patients, 99.5% by IV route. The latter was consistent with the US dialysis population at large but in variance with DOQI preference for the subcutaneous route. The target Hct range of 33–36 was found in 33%, with a mean Hct of 34.0 ± 0.12. When the data were reanalyzed by excluding patients who had not been receiving erythropoietin and had not been on dialysis for at least 3 months, the percentage of patients achieving the target Hct increased to 37%. Paired analysis of 875 patients present in 1996 and 1998 showed that, although there was a marked increase in the use of IV iron, the improvement in anemia was modest, and there was evidence for increased iron accumulation. In summary, this 1998 survey on the clinical practice of anemia management in a large hemodialysis population indicates that there is a marked increase in need-based IV iron usage that was associated with modest improvement in anemia and evidence for increased iron storage. A maintenance iron dosing protocol with smaller doses of iron, such as 25 mg of iron dextran per hemodialysis, may make bioavailable iron continuously present for erythropoiesis, yet may reduce the chance for iron catalyzed lipid peroxidation and tissue iron deposition.