Comorbid insomnia symptoms predict lower 6-month adherence to CPAP in US veterans with obstructive sleep apnea

There is limited information on the association between pre-treatment insomnia symptoms and dysfunctional sleep beliefs with continuous positive airway pressure (CPAP) adherence in veterans with obstructive sleep apnea (OSA). Our aims were to describe demographic and sleep characteristics of veterans with and without comorbid insomnia and determine whether pre-treatment insomnia symptoms and dysfunctional sleep beliefs predict CPAP use after 6 months of therapy. Hispanic veterans attending the Miami VA sleep clinic were recruited and completed the insomnia severity index, the dysfunctional sleep belief and attitude scale (DBAS), and other questionnaires. Participants were asked to return after 7 days and 1 and 6 months to repeat questionnaires and for objective CPAP adherence download. Hierarchical regression models were performed to determine adjusted associations of pre-treatment insomnia symptoms and DBAS sub-scores on 6-month mean daily CPAP use. Fifty-three participants completed the 6-month follow-up visit with a mean CPAP use of 3.4 +/- 1.9 h. Veterans with comorbid insomnia had lower mean daily CPAP use (168 +/- 125 vs 237 +/- 108 min, p = 0.04) and lower percent daily CPAP use 4 h (32 +/- 32 vs 51 +/- 32%, p = 0.05) compared to participants without insomnia. In adjusted analyses, pre-treatment insomnia symptoms (early, late, and aggregated nocturnal symptoms) and sleep dissatisfaction were predictive of lower CPAP use at 6 months. Pre-treatment dysfunctional sleep beliefs were not associated with CPAP adherence. Pre-treatment nocturnal insomnia symptoms and sleep dissatisfaction predicted poorer 6- month CPAP use. Insomnia treatment preceding or concurrent with CPAP initiation may eliminate a barrier to regular use.