[Sleep disorders in patients with chronic renal insufficiency in long-term hemodialysis treatment]

Of 22 patients on maintenance hemodialysis investigated during a period of 20 days for sleep disturbances by means of a semistructured questionnaire, 14 patients reported sleep disturbances. The patient group was found to be homogeneous with respect to factors influencing sleep behavior, such as age, personality and comedication. The sleep disturbances of the dialyzed patients was characterized by diminished sleep efficiency (time asleep/time in bed) and more fragmented sleep, while time of lying in bed awake was perceived as particularly disturbing. The sleep disturbance could be interpreted as a form of secondary metabolically induced insomnia. A single dialysis caused increased fatigue and diminution of well-being, but also an increase in the first fragment of sleep and of the total duration of sleep, i.e. it induced a modification toward a more physiologic sleep pattern. The retention of "middle molecules" could be of importance for the occurrence of uremic sleep disturbance. Patients who were underdialyzed relative to middle molecules were more numerous in the group with disturbed sleep, but the difference did not reach significance in the small number of subjects studied.