Continuous Positive Airway Pressure Treatment and Depression in Adults with Coronary Artery Disease and Nonsleepy Obstructive Sleep Apnea. A Secondary Analysis of the RICCADSA Trial

RATIONALE: Obstructive sleep apnea (OSA) and depression are common among adults with coronary artery disease (CAD). OBJECTIVES: To determine the impact of continuous positive airway pressure (CPAP) treatment on depression in adults with CAD and nonsleepy OSA. METHODS: This was a secondary analysis of the RICCADSA (Randomized Intervention with CPAP in CAD and Sleep Apnea) trial, conducted in Sweden between 2005 and 2013. Adults with CAD and nonsleepy OSA (apnea-hypopnea index ≥15/h, and Epworth Sleepiness Scale <10 at baseline) and complete Zung Self-Rating Depression Scale (SDS) questionnaires at baseline, after 3 and 12 months, were included. Participants analyzed in their randomized arm were CPAP (n = 99) or no-CPAP (n = 104). Depression was defined as a Zung SDS score of 50 or greater. The primary outcome was the between-group difference in the absolute change in the SDS score from baseline. RESULTS: No significant between-group differences were observed in SDS scores during follow-up in the entire study sample. Among the 56 participants with an SDS of 50 or greater at baseline (27.6%), the mean (±SD) baseline SDS was 55.0 (±5.5) in the CPAP group, and 53.9 (±4.0) in the no-CPAP group. In the CPAP group, SDS scores decreased at 3 months (47.2 ± 8.2) and 12 months (45.8 ± 7.6), but remained stable in the no-CPAP group at 3 months (53.1 ± 8.0) and 12 months (52.6 ± 8.1) (P = 0.01). The proportion with depression decreased from 30.3% at baseline to 16.2% after 3 months, and to 13.1% after 12 months in the CPAP group, from 25.0% at baseline to 23.1% after 3 months, and to 24.0% after 12 months in the no-CPAP group (P = 0.001). Moreover, there was an association between the duration of CPAP usage (h/night) and the longitudinal decline in SDS score (r = 0.46; P < 0.001). CPAP usage categories (3, 4, and 5 h/night) were significantly associated with improvement in SDS (odds ratio = 3.92, 4.45, and 4.89, respectively) in multivariate analyses adjusted for age, sex, body mass index, left ventricular ejection fraction, apnea-hypopnea index, and Epworth Sleepiness Scale at baseline. CONCLUSIONS: Among adults with depression, nonsleepy OSA, and CAD, 3 months of CPAP treatment improved depression scores. The improvement in mood persisted up to 12 months. An on-treatment adjusted analysis confirmed these findings. Clinical trial registered with www.clinicaltrials.gov (NCT00519597).