Prevalence and predictors of sleep disordered breathing in patients undergoing chronic ambulatory intermittent hemodialysis

Abstract

Sleep disordered breathing (SDB) is a common finding in chronic hemodialysis (CHD) patients. Two recent American studies investigated the prevalence of SDB in patients with different degree of chronic kidney disease and reported a prevalence of 26–57%. The purpose of this study is to evaluate the prevalence of SDB and to evaluate the predictive value of Berlin questionnaire, hemodialysis frequency and duration, and biometric parameters in a large group of European patients undergoing CHD. All the patients attending six CHD centers in the western part of Switzerland were screened. Eligible patients completed the Berlin questionnaire, a validated 11 items form used to evaluate the risk of obstructive sleep apnea and the Epworth Sleepiness Scale (ESS). All patients underwent a home nocturnal polygraphy (PG) using Apnea Link Plus system recording nasal pressure, oxygen saturation, thoracic movements and heart rate. Respiratory events were scored according to the AASM 99 criteria. Apnea-hypopnea index (AHI) was calculated by dividing the total number of apnea and hypopnea during the night by the recording time. Among 166 screening patients, 98 were included and 71 completed the study (50 men, mean age 61.8 ± 15.4, neck circumference 40.6 ± 4.6 cm, BMI 25.7 ± 4.8 kg/m2). Mean AHI was 23.9 ± 20.4/h (18% obstructive apnea, 8.5% central apnea, 2.4% mixed apnea). Among these 71 patients, 31% had severe SDB (AHI ⩾ 30/h), 23.9% had moderate SDB (AHI 15–30/h), 31% had mild SDB (AHI 5–15/h) and 14.1% were normal (AHI < 5/h). Berlin’s questionnaire showed a high risk of SDB in 62.5% of the patients with a sensitivity of 65%, a specificity of 39%, a positive predictive value of 58% and a negative predictive value of 47%. According to ESS, 18.5% of the patients had significant sleepiness (>10/24). Using a logistic regression model including age, sex, BMI, neck circumference, Berlin questionnaire, ESS, smoking, alcohol, number/week and duration of CHD session, the only independent predictor was neck circumference with odds ratio of 1.59 (p = 0.023). The prevalence of SDB in the CHD population is higher than expected. Berlin questionnaire is not useful to screen for SDB in CHD patients but neck circumference seems to be an independant predictor of SDB in this population. Supported by the Leenaards Foundation, Ligue Pulmonaire Vaudoise, Swiss National Foundation for Research, GSK.