Insomnia related to sleep apnoea: effect of long-term auto-adjusting positive airway pressure treatment.

Insomnia related to sleep apnoea (IA) is highly prevalent, and its proper treatment is still debated. The aim of this study was to test the hypothesis that long-term auto-adjusting positive airway pressure (APAP) treatment improves IA symptoms. 80 patients (mean±sd age 54.9±10.6 yrs, respiratory disturbance index (RDI) 45.0±24.6 events·h(-1)) receiving APAP treatment were followed prospectively for 24 months. Somnolence and depression were assessed at baseline (T0) with the Epworth and the QD2A scales, respectively. Nightly APAP use was measured after 24 months of treatment (T24). The assessment of insomnia at T0 and T24 used the insomnia severity index (ISI). The combination of ISIT0 ≥15 and ISIT0-ISIT24 ≥9 defined the APAP-responding insomnia (APAP-RI) group. A logistic regression analysis identified the factors independently associated with the APAP-RI group. The ISI (13.7±5.7 versus 8.2±6.3) decreased significantly from T0 to T24 (p = 0.0001) for the patients as a whole, with a mean decrease of 13.5±2.9. Among the 39 insomniac subjects (T0), 20 belonged to the APAP-RI group (51%). The Epworth score (OR 1.536, 95% CI 1.093-2.159; p = 0.01) and the RDI (OR 1.080, 95% CI 1.010-1.154; p = 0.02) increased the risk of belonging to the APAP-RI group. IA symptoms improved with APAP treatment, and improvement was associated with the initial severity of the disease and somnolence in our population.