A small study in the Aug. 15 issue of the Journal of Clinical Sleep Medicine examined the sleep quality of people with both kidney failure and obstructive sleep apnea.
The study involved 30 adults with moderate to severe OSA; 12 of them had kidney failure – also called end-stage renal disease. The other 18 people had normal kidney function.
Results show that people with normal kidney function slept for about 5.5 hours during an overnight sleep study; but people with kidney failure slept for only 4.4 hours.
Why was their sleep so disrupted? In large part it was because of frequent periodic limb movements.
People with kidney failure had about 31 PLM per hour of sleep; these movements caused almost 15 arousals per hour. In contrast, people with normal kidney function had only one arousal per hour caused by PLM.
The authors report that OSA is extremely common in people with kidney failure. But sleep disruptions tend to persist even after treating OSA with CPAP therapy.
The study shows that PLM may contribute to the problem; the authors conclude that treating PLM may improve sleep quality in people with OSA and kidney failure.
The AASM reports that PLM involve simple, repetitive muscle movements. Usually a lower-leg muscle tightens or flexes. A typical movement is for the big toe to extend. Often the ankle, knee or hip also will bend slightly. People with PLM often have restless legs syndrome too. Medications can treat both PLM and RLS.
Kidney failure commonly is treated by hemodialysis. Blood is drawn from the body, cleaned and pumped back into the body. In May the Sleep Education Blog reported that some dialysis clinics now offer to perform the treatment while patients sleep.