When assessing sleep performance in dialysis patients, objective measures of sleep quality should be preferred to the PSQL

We read with interest the article by Parmaksiz et al. on an observational cross-sectional study of sleep quality, measured using the Pittsburgh Sleep Quality Index (PSQI), in 51 patients who had been receiving hemodialysis (HD) for more than one year and 23 patients who had been receiving peritoneal dialysis (PD) for more than one year. 1There was no difference in sleep quality between HD and PD patients in the PSQI, but HD patients had a longer sleep onset latency and more severe daytime disturbances compared to PD patients. 1It was concluded that sleep disturbances in dialysis patients should be treated. 1The study is interesting, but some points should be discussed.The first point is that sleep quality depends not only on whether the patient receives HD or PD treatment, but also on several other endogenous or exogenous factors. 2 Endogenous factors that additionally influence sleep performance include personality type, acute and chronic stress (balance between the sympathetic and parasympathetic nervous systems), the ability to cope with exogenous or endogenous stressors, genetic predisposition, comorbidities, and lifestyle habits (e.g., sleep habits (going to bed at a specific time, turning off the TV, headphones, radio, cell phone, iPad, and bedroom lights, removing stale air and all devices