Impact of sleep quality and comorbidities on health-related quality of life in patients with obstructive sleep apnea

Aim: To investigate whether sleep quality and comorbidities are independent predictors of impaired health-related quality of life (HRQL) in patients with obstructive sleep apnea (OSA). Methods: Two hundred and twenty-four patients with OSA (AHI>5/hour) were studied using the validated greek translations the SF-36 and SF-12 questionnaires, the Medical Outcomes Study Sleep Scale (MOS-SS) and the Functional Comorbidity Index (FCI). Each of the SF-36 and SF-12 questionnaires yields two composite subscores, the physical (PCS-36 and PCS-12) and the mental (MCS-36 and MCS-12) subscore. MOS-SS interrogates 6 sleep domains: disturbance, adequacy, quantity, somnolence, snoring and headache/breathlessness. FCI registers the presence of 18 comorbidities which are associated with impaired SF-36 scores. Results: PCS-36 and PCS-12 were significantly correlated with sleep disturbance (Rho: -0.296 and -0.314, respectively), headache/breathlessness (Rho: -0.268 and -0.277) and FCI (Rho: -0.451 and -0.406). MCS-36 and MCS-12 were significantly correlated with sleep disturbance (Rho: -0.363 and -0.367), headache/breathlessness (Rho: -0.367 and -0.304), sleep adequacy (Rho: -0.282 and -0.251) and somnolence (Rho: -0.301 and -0.326). Sleep disturbance, headache/breathlessness and FCI were independent predictors for PCS-36 and PCS-12 (adjusted R2: 0.284 and 0.260). Sleep disturbance and headache/breathlessness were independent predictors of MCS-36 and MCS-12 (adjusted R2: 0.230 and 0.234). Conclusions: In patients with OSA, sleep quality determines both the physical and the mental component of HRQL, while the physical component is additionally influenced by comorbidities.