Self-reported sleep apnoea and mortality in patients from the Swedish Obese Subjects study

Sleep apnoea is associated with increased mortality in sleep clinic and community population groups. It is unclear whether a clinical report of sleep apnoea results in additional mortality risk in patients with severe obesity. The Swedish Obese Subjects (SOS) study is a nonrandomised controlled trial of bariatric surgery versus conventional treatment for the treatment of severe obesity and its complications (mean ± SD body mass index 41 ± 5 kg · m(-2)). The presence or absence of sleep apnoea (witnessed pauses in breathing) was determined by self-reporting at baseline in 3,953 patients who were observed for 54,236 person-yrs (mean 13.5 maximum 21.0 yrs). Sleep apnoea was reported by 934 (23.6%) patients at baseline and was a significant univariate predictor of mortality (hazard ratio (95% CI) 1.74 (1.40-2.18)). In a range of multivariate models of mortality risk, controlling for ≤ 16 other potential confounders and established mortality risk factors, sleep apnoea remained a significant prognostic factor (fully adjusted model 1.29 (1.01-1.65)). Self-reported sleep apnoea is an independent prognostic marker of all-cause mortality in obese patients.