1176 REM Sleep in Patients with Comorbid Fibromyalgia and Obstructive Sleep Apnea versus OSA Only Patients

Abstract Introduction In Obstructive Sleep Apnea (OSA) patients, treatment with continuous positive airway pressure (CPAP) increases rapid eye movement (REM) sleep, highlighting the potential for sleep restoration. Fibromyalgia (FM) is a chronic pain condition often co-occurring with OSA and associated with sleep disturbances. REM sleep plays a key role in pain modulation, and REM deprivation has been linked to increased pain sensitivity, a core symptom of FM. In healthy adults, REM comprises ~25% of total sleep time, and reduced REM may alter pain perception. We hypothesize that patients with comorbid OSA and FM will exhibit reduced REM sleep compared to OSA alone, suggesting a mechanism by which FM may exacerbate pain and sleep-related symptoms in this population. Methods This IRB-approved retrospective chart review identified patients with FM and OSA through EPIC using diagnostic codes (ICD 10: M79.7, G47.33; ICD-9: 729.1, 327.23). FM+OSA patients were collected from 2012–2018 and OSA-only patients from 2019–2024. Polysomnography reports were reviewed for REM latency, REM duration, and REM percentage of total sleep time (TST) using supercomputer analysis. weight and BMI were collected from EPIC demographics. Results A total of 433 patients with FM+OSA and 250 patients with OSA only were included. The FM+OSA group was predominantly female (379/433). Average REM duration was 39.3 minutes in the FM+OSA group versus 45.5 minutes in the OSA-only group, a 6.2-minute difference (p < 0.01). REM percentage of TST was 12.6% in FM+OSA versus 14.4% in the OSA only group, reaching marginal statistical significance (Fisher exact test statistic= 0.0969, p < 0.10). Conclusion Both OSA and FM+OSA patients exhibited reduced REM sleep compared to population norms, with FM contributing an additional reduction in REM sleep, both in absolute minutes and as a percentage of total sleep time. This greater REM loss in FM+OSA supports the hypothesis that altered REM sleep may explain the heightened pain burden in FM. Prospective studies are needed to determine whether reduced REM directly influences pain perception in FM and whether interventions that restore REM sleep can mitigate pain. Support (if any)