Supplemental Oral Nutrition Benefits Hemodialysis Patients
HONOLULU—Hemodialysis (HD) patients who take oral nutritional supplements (ONS) while dialyzing have improved survival and other benefits, according to findings released here at the 16th International Congress on Nutrition and Metabolism in Renal Disease.
In a symposium, Raymond Hakim, MD, PhD, a consultant nephrologist at Vanderbilt University Medical Center in Nashville, Tenn., presented results indicating that providing ONS during dialysis reduces patients' risk of death by up to 34% compared with not receiving ONS. The study was also published online ahead of print in the American Journal of Kidney Diseases (AJKD).
“We think our study has been critical in showing that providing malnourish patients with ONS attenuates the deficit of amino acids that occurs during dialysis and reduces mortality,” Dr. Hakim told Renal & Urology News. “It's important that malnourished patients receive ONS during dialysis because that's when they do not eat or have any oral intake for at least four hours, while they lose significant amounts of amino acids along with uremic toxins in the dialysate.”
Dr. Hakim, Eduardo Lacson Jr., MD, MPH, and others retrospectively studied 7,264 people who received ONS during HD (case patients) at Fresenius Medical Care North America (FMCNA) facilities and had at least one albumin level of 3.5 g/dL or less. They compared their outcomes to those from another 21,347 patients who also had at least one albumin level of 3.5 g/dL or less but did not receive ONS (controls). None of the subjects was receiving ONS outside of the HD center. The patients receiving ONS could choose among four products: NeproCarb Steady, ProStat RC, ZonePerfect, and VitalProteinRX.
The study included an intent-to-treat (ITT) population consisting of 5,227 case patients propensity-score matched with 5,227 controls. From the same patient population, they created an as-treated cohort consisting of 4,289 case patients propensity-score matched with 4,289 controls.
The characteristics of the matched pairs in both the ITT and as-treated analyses were similar, including mean baseline albumin levels of 3.3 g/dL in all groups. However, the as-treated ONS patients had been on dialysis slightly longer than the as-treated control patients, with a mean of 3.89 vs. 3.60 years.
The crude death rates in the ITT cohort were 30.1% for the ONS group and 30.4% for the controls, while they were 30.9% and 37.3%, respectively, in the as-treated cohort. These extremely high death rates reflect that hypoalbuminemic patients belonged to the worst risk group in the maintenance HD population because they are severely malnourished, the investigators explained in the AJKD paper.
Overall, ONS patients had 9% increased survival than controls in the ITT analysis and 34% increased survival in the as-treated analysis. The difference in outcomes between the two models is because in the ITT analyses, 40% of the patients in the control group did receive some ONS during the follow-up period. Additional analyses showed that the greatest effect of supplements on the death rate was among those with baseline albumin levels of 3.2 g/dL or less. In other words, the worse the malnutrition, the more effective is ONS.
The observed difference in survival represents a major finding that supports what has long been proposed: that increasing protein and caloric intake during thrice-weekly HD treatments “may facilitate achieving sufficient nutritional support and improve physiologic processes enough to reduce their high risk of mortality,” Dr. Hakim and his colleagues stated in their paper. They strongly recommended “that intradialytic oral nutrition be offered as a treatment option to eligible hypoalbuminemic maintenance-hemodialysis patients.”
In a separate presentation at the meeting, Dr. Lacson, using the same study population, showed that intradialytic ONS reduces the risk of hospitalization and the length of hospital stay compared to not receiving intradialytic ONS. The time to first hospitalization was significantly shorter in intradialytic ONS patients compared with controls. The average hospitalization rates were 2.5 and 2.7 episodes/patient-year in the two groups, respectively. In addition, the ONS and controls group had 19.2 and 20.4 hospitalization days/patient-year, respectively, and 29.4% and 36.6% mortality rates, respectively.
Also at the symposium, T. Alp Ikizler, MD, also of Vanderbilt, stressed the importance of boosting nutrition among patients with chronic kidney disease (CKD) when indicated, an approach used widely around the world but not in North America.
Although eating meals during dialysis potentially could be associated with a small risk of hypotension and some inconvenience for dialysis center staff, it can counteract HD-related protein catabolism, improve patients' nutritional status, increases their dialysis adherence, and enhance phosphate and fluid removal, Dr. Ikizler said. He discussed these points in detail in a recent review article, which also included a proposed algorithm for nutritional support in CKD patients (Nature Rev Nephrol 2011;7:369-384). He also discussed the algorithm in detail at the congress.