Smoking status, clinical presentation and outcomes in obstructive sleep apnoea

Rationale . The effect of tobacco on obstructive sleep apnoea (OSA) is well-documented but its effect on the OSA severity and cardiovascular (CVS) outcomes has not been established Methods. In the frame of the Zaragoza Sleep cohort we retrospectively evaluate the clinical presentation, OSA severity and CVS outcomes of subjects. Participants were recoded as “have never been smokers” (non-smokers) or “active or past smokers” (smokers). Baseline demographic, anthropometric, and comorbidities were recorded on study inclusion. Apnoea-hypopnoea index (#episodes of apnoeas/hypopnoeas per hour of sleep –AHI-) was calculated from in-hospital or at home validated sleep studies. During follow-up, CVS events (myocardial infarction, Heart failure, stroke) were annually recorded. Results. Among 3771 patients who were not treated with CPAP, 43% were smokers. Age and body-mass index (BMI) were similar in smokers and non-smokers. Nevertheless, mean AHI (35.8 vs 29.9, p 30) than non-smokers (OR = 2.7; P=0.001). There was 632 CVS events during follow-up: 12.3% in non-OSA (AHI<10) and 18.1% in OSA patients (p<0.001). In Cox regression analysis, smoking status independently predict CVS events in addition of age, systolic blood pressure, BMI, Charlson Index and AHI. Conclusions . Smoking habits seems to be associated with the severity of OSA and CVS outcomes. These results underline the importance of smoking cessation in the treatment of patients with OSA. Supported by ISCIII grant PI12/02175, SADAR/2013 and SEPAR/2013.