Peanuts or Pretzels? Changing Attitudes about Eating on Hemodialysis.

I am not that fond of peanuts, and I hate pretzels, but when stuck on an airplane flight, I smile when the flight attendant offers them. This is not because I am hungry, and I certainly do not need the calories. My pleasure is less in the food itself and more in the small ritual of hospitality that marks the midpoint of the flight. Food makes most people feel welcome and appreciated, and patients on dialysis are not different. Eating at least breaks the monotony of being tied to a chair for hours. Unlike airline passengers, many patients on dialysis have protein-energy wasting (PEW) syndromes and could potentially benefit from the additional protein and calories (1). As tempting as it may be to compare dialysis units to discount airlines that withhold peanuts or pretzels from their passengers, there are historical reasons why American dialysis units have frequently banned eating on dialysis. When maintenance hemodialysis in hospital-based units began in the 1960s, inefficient dialysis meant treatment times over 24 hours, and therefore, units provided meals (2). By 1976, the standard treatment was 8 hours of dialysis three times a week, and patients ate a meal that they brought if they were not provided with one. As dialysis became more efficient, treatment times were shortened, and with more rapid volume and solute removal, hemodynamic instability became a challenge (3). Importantly, hypotension seemed to be more common among patients who had recently eaten, and additional investigation identified a postprandial fall in systemic vascular resistance as the most likely mechanism (4,5). Although there are no case reports of aspiration from eating on dialysis, newspaper articles do show a few such lawsuits (6). Thus, many American hemodialysis units banned eating on dialysis. In contrast, European and Asian dialysis units did not reduce dialysis times to the same extent as American units, and a much larger percentage of these units continued toprovidemeals for theirpatients or allowed patients to bring their own food. Concern that eating may be beneficial for PEW is counterbalanced with concern for hypotension in European guidelines on hemodynamic instability on dialysis (7). Although no systematic study has been performed, relatively few complications were noted in a recent survey of European and Asian units that continue the practice (8). Thus, although there has been diversity in practice worldwide, American units became less likely than units in other countries to allow eating during treatment. Modern proponents of eating on dialysis do not dispute effects of postprandial physiology on BP, but theyargueagainst its clinical significance (9,10). In their eyes, clinically significant negative effects were only seen with large meals, large fluid intake, or meals late in the dialysis session. They note correctly that many studies occurred in an era when some patients were still on acetate dialysate and before biocompatible membranes, volumetric ultrafiltration, lowtemperature dialysis, and limits on hourly ultrafiltration were common. For example, they cite a study performed in 2008 over three treatments in 126 patients in whom there were no effects of eating on any measure of BP (11). Furthermore, they argue that there may be significant benefits of eating on dialysis for patients with PEW. First, they note that oral nutrition when used as a control in studies of intradialytic parenteral nutrition was associated with improved albumin and outcomes (12). The loss of amino acids that occurs with dialysis is intensely catabolic for muscle, and radiotracer studies confirmed that the slow delivery of amino acids to the bloodstream in the postprandial state provided excellent delivery of amino acids to muscle (13,14). Patients who ate on dialysis consumed more protein and more calories (15) and reported a higher quality of life (16). In a retrospective, observational study, patients with PEW defined by a serum albumin of ,3.5 mg/dl who received oral supplements containing 15 g protein on or before dialysis had a 29% decrease in mortality compared with matched control subjects in a 14-month follow-up (17). However, eating on dialysis did not help patients without PEW in the few available studies (18). Given the growing data on the relative safety and possible benefits of oral nutrition before or during hemodialysis, have there been changes in practices of United States hemodialysis units? In this issue of the Clinical Journal of the American Society of Nephrology, Benner et al. (19) examine surveys on eating in dialysis units completed by dietitians in units owned by DaVita Healthcare Partners, Inc., a leading United States dialysis provider. The surveys reported on both practices around oral nutrition and attitudes of the dietitian, facility manager, and medical director toward eating on hemodialysis. After an initial survey in 2011 Medical Subspecialties Service Line, Atlanta Department of Veterans Affairs Medical Center, Decatur, Georgia; and Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia