Mortality of sleep apnoea patients treated by nasal continuous positive airway pressure registered in the ANTADIR observatory

The aim of this study was to examine risk factors for and causes of mortali ty in patients with obstructive sleep apnoea syndrome (OSAS) treated by nas al continuous positive airway pressure (CPAP). Univariate and multivariate analyses of the data on patients registered in the Association Nationale pour le Traitement A Domicile de l'Insuffisance R espiratoire chronique (ANTADIR) observatory between January 1, 1985 and Dec ember 31, 1993 and followed to January 1, 1996, Survival ratios were compar ed to those of the French population. A case control study compared patient s who died with patients of the same age and sex, in the same Regional Asso ciation, who were equipped with CPAP at the same time. Five-thousand-six-hu ndred-and-sixty-nine patients had CPAP treatment. Two-hundred-and-seventy-s ix had died. One-hundred-and-twenty-four deaths were examined and compared to 123 control subjects. Overall mortality was, the same as the general French population. Independe nt risk factors for death were age, oxygen tension in arterial blood (Pa,O- 2) and forced expiratory volume in one second (FEV1) (per cent predicted). In the case-control study independent risk factors for death in the past hi story were cardiac arrhythmia with an odds ratio (OR) of 2.8 (95% confidenc e interval (CI) 1.1-7.2), respiratory disorders (OR 2.8; CI 1.6-;4.9) ischa emic events (OR 2.2; CI 1.2-4.2), neurological and psychiatric disorders (O R 2.4; Cf 1.1-5.4). A significant excess of cardiovascular deaths and an ex cess of deaths from accidents and poisonings was found. In conclusion, patients die on therapy predominantly from cardiovascular ca uses but many have a past history of cardiovascular conditions. Compliance with treatment may be important for survival. Continuous positive airway pr essure is an effective therapy for obstructive sleep apnoea syndrome but ol der patients with reduced spirometry and hypoxaemia may need more attention paid to these aspects of their condition.