Prognostic value of lung function and pulmonary haemodynamics in OSA patients treated with CPAP

The aim of the present study was to determine survival rates of obstructive sleep apnoea patients treated with continuous positive airway pressure (CP AP) and to investigate the prognostic value of pretreatment lung function a nd pulmonary haemodynamics. Two hundred and ninety-six patients, exhibiting greater than or equal to 20 apnoeas plus hypopnoeas per hour of sleep, were included. Patients were tr eated with nasal CPAP and regularly followed up. The cumulative survival rates were 0.96 (95% confidence interval (CT): 0.94 -0.99) at 3 yrs and 0.93 (95% CI: 0.91-0.97) at 5 yrs. Most patients died f rom cardiovascular disease. Apart from age, covariates associated with a lo wer survival were the presence of a heavy smoking history, a low vital capa city, a low forced expiratory volume in one second (FEV1) and a high mean p ulmonary artery pressure. Only three covariates were included by forward st ep,vise selection in the multivariate analysis, smoking habit (>30 pack-yrs ), age and FEV1. The observed survival rates of the group as a whole were s imilar to those of the general population matched in terms of age, sex and smoking habit, except for patients between 50 and 60 yrs old who had reduce d survival. This difference disappeared when patients of the present study with an associated chronic obstructive pulmonary disease were excluded from the comparison. In conclusion, survival of obstructive sleep apnoea patients treated,vith n asal continuous positive airway pressure is near to that of the general pop ulation. The prognosis is worse in subgroups of patients,vith a history of heavy smoking and with an associated chronic obstructive pulmonary disease.