Age and underdialysis as predictors of sleep disorders in peritoneal dialysis patients

MUSSO CG

INTERNATIONAL UROLOGY AND NEPHROLOGY

SPRINGER

Lugar: Berlin; Año: 2005

0301-1623

We read with interest the paper by Kurella et al. [1],recently published in your journal. The authorsstudied the quality of sleep among patients onmaintenance hemodialysis as well as among predialysischronic kidney patients. They assessedquality of sleep using the Kidney Disease Quality ofLife (KDQOL) sleep scale, where higher scoresrepresent a better self-assessed quality of sleep.The most important findings of the study can besummarized as follows: sleep disorders were prevalentin 34% of hemodialysis patients and rangedfrom 14% to 27% in pre-dialysis patients with moderateor advanced renal impairment respectively.KDQOL results directly correlated with age and thedifference between sleep disorders among dialysisand pre-dialysis patients was prominent amongyounger subjects and attenuated among older subjects.In a retrospective analysis published by our teamin 2004 in your journal [2] we found a prevalence ofsome degree of insomnia in 36% of 104 peritonealdialysis (PD) patients who had some evidence (clinicalor laboratory indices) of underdialysis. Afterincreasing dialysis dose (peritoneal Kt/V rose from1.8?0.1 to 2.27?0.1) the prevalence of insomnia decreasedsignificantly from 36% to 18% (P=0.0002,Mc Nemar?s test). In a reanalysis of our data wefound that there was no difference in the age of patientswith or without insomnia before the increase indialysis dose (P=ns, unpaired t-test). On the contrary,6 months after dialysis dose was increased, the patientswith insomnia had a higher mean age thanthose without sleep problems (61.7?9 vs. 52.2?15,P=0.01). In a logistic regression model which includedage, duration on dialysis therapy, serum creatinineand phosphorous (parameters that Kurellaet al. [1] reported to correlate with sleep quality) asindependent variables, only age was a significantpredictor of poor quality of sleep and only after theincrease in dialysis dose (P=0.01).