Obstructive sleep apnea and objective sleep quality in non-dialyzed patients with chronic kidney disease: an ESADA study

Background: Altered sleep quality has been reported in chronic kidney disease (CKD). However, most studies focused on dialyzed patients or were based on subjective reports that did not consider possible coexistence of obstructive sleep apnea (OSA). Aim: To evaluate, with a case-control design, if objective sleep quality differs between patients with stage 3 CKD and subjects with normal estimated glomerular filtration rate (eGFR) independent of sleep disordered breathing. Methods: In the European Sleep Apnea Database (ESADA) cohort, 527 patients who had undergone full polysomnography and had an eGFR<60 ml/min/1.73m2 were matched for sleep centre, age, sex and apnea/hypopnea index (AHI), one-by-one, with patients with eGFR>60. Results: CKD patients were slightly more obese, had worse sleep hypoxemia, and had more comorbidities than controls, including arterial hypertension, type 2 diabetes, and congestive heart failure. However, they did not differ from controls in any objective sleep parameter. When the sample was subdivided into three groups according to AHI tertiles, cases and controls were similar within each group. Total sleep time, sleep efficiency, % of stages N3 and R decreased, while stage N2 increased, with increasing OSA severity (all p<0.001). Conclusions: In subjects with eGFR>60 and in patients with stage 3 CKD, objective sleep duration and quality did not differ, and changed in parallel with AHI. Previously reported poor sleep quality and duration in CKD may partly be due to a high prevalence of OSA.