Risk factors for, and prevalence of, sleep apnoea in cardiac rehabilitation facilities in Germany: The Reha-Sleep registry

Abstract

Aim: To determine the prevalence of, and the risk factors for, sleep apnoea in cardiac rehabilitation (CR) facilities in Germany. Methods: I 152 patients presenting for CR were screened for sleep-disordered breathing with 2-channel polygraphy (ApneaLink ResMed). Parameters recorded included the apnoea-hypopnoea index (AHI), number of desaturations per hour of recording (ODI), mean and minimum nocturnal oxygen saturation and number of snoring episodes. Patients rated subjective sleep quality on a scale from I (poor) to 10 (best) and completed the Epworth Sleepiness Scale (ESS). Results: Clinically significant sleep apnoea (AHI ≥l5/h) was documented in 33% of patients. Mean AHI was 14 ± 16/h (range 0-106/h). Sleep apnoea was defined as being of moderate severity in 18% of patients (AHI ≥ 15-29/h) and severe in 15% (AHI ≥30/h). There were small, but statistically significant, differences in ESS score and subjective sleep quality between patients with and without sleep apnoea. Logistic regression model analysis identified the following as risk factors for sleep apnoea in CR patients: age (per 10 years) (odds ratio (OR) 1.51; p < 0.001), body mass index (per 5 units) (OR 1.31; p = 0.001), male gender (OR 2.19; p< 0.001), type 2 diabetes mellitus (OR 1.45; p = 0.040), haemoglobin level (OR 0.91; p = 0.012) and witnessed apnoeas (OR 1.99; p < 0.001). Conclusions: The findings of this study indicate that more than one-third of patients undergoing cardiac rehabilitation in Germany have sleep apnoea, with one-third having moderate-to-severe SDB that requires further evaluation or intervention. Inclusion of sleep apnoea screening as part of cardiac rehabilitation appears to be appropriate.