The effect of prolonged intradialytic exercise in hemodialysis efficiency indices.

Optimal hemodialysis (HD) dose is very important to patients' health and survival, and various indices of adequacy have been incorporated into the current clinical practice to monitor HD efficiency. Exercise during HD could facilitate solute removal; however, it is still unknown whether prolonged intradialytic exercise could further improve HD efficiency. Ten stable "high-functioning" HD patients volunteered to participate. The patients were studied under two scenarios during HD: 1) supine exercise (cycling) for 3 hours at 40% of maximum exercise capacity and 2) no exercise as usual. Blood sampling was acquired pre- and post-HD in both scenarios to calculate the HD efficiency indices. All patients completed the exercise regime with no adverse effects. Rather, all efficiency indices significantly improved in the prolonged exercise scenario, compared with the no-exercise one. In particular Kt/V, urea reduction ratio, and creatinine reduction ratio significantly improved by 20%, 11%, and 26%, respectively, while potassium plasma levels were reduced by 77.5% (p < 0.05). In conclusion, prolonged low-intensity intradialytic exercise improved HD efficiency, with no adverse effects. HD patients should be encouraged to participate in exercise regimes not only for the known long-term benefits regarding their cardiovascular health but also for the acute effect of exercise in the HD adequacy.

Liver fat, visceral adiposity, and sleep disturbances contribute to the development of insulin resistance and glucose intolerance in nondiabetic dialysis patients.

Hemodialysis patients exhibit insulin resistance (IR) in target organs such as liver, muscles, and adipose tissue. The aim of this study was to identify contributors to IR and to develop a model for predicting glucose intolerance in nondiabetic hemodialysis patients. After a 2-h, 75-g oral glucose tolerance test (OGTT), 34 hemodialysis patients were divided into groups with normal (NGT) and impaired glucose tolerance (IGT). Indices of insulin sensitivity were derived from OGTT data. Measurements included liver and muscle fat infiltration and central adiposity by computed tomography scans, body composition by dual energy X-ray absorptiometer, sleep quality by full polysomnography, and functional capacity and quality of life (QoL) by a battery of exercise tests and questionnaires. Cut-off points, as well as sensitivity and specificity calculations were based on IR (insulin sensitivity index by Matsuda) using a receiver operator characteristics (ROC) curve analysis. Fifteen patients were assigned to the IGT, and 19 subjects to the NGT group. Intrahepatic fat content and visceral adiposity were significantly higher in the IGT group. IR indices strongly correlated with sleep disturbances, visceral adiposity, functional capacity, and QoL. Visceral adiposity, O2 desaturation during sleep, intrahepatic fat content, and QoL score fitted into the model for predicting glucose intolerance. A ROC curve analysis identified an intrahepatic fat content of > 3.97% (sensitivity, 100; specificity, 35.7) as the best cutoff point for predicting IR. Visceral and intrahepatic fat content, as well as QoL and sleep seemed to be involved at some point in the development of glucose intolerance in hemodialysis patients. Means of reducing fat depots in the liver and splachnic area might prove promising in combating IR and cardiovascular risk in hemodialysis patients.