Evaluation of sleep architecture and functional level in Fibromyalgia patients with and without obstructive sleep apnea syndrome I. Bouloukaki1, L. Konstantara1, C. Mermigkis1, R. Pateli1, V. Moniaki1, E. Mauroudi1, S. Schiza1 1 Sleep Disorders Center, Department of Thoracic Medicine, University of Crete, Heraklion, Greece BACKGROUND: Clinical and epidemiological studies show that sleep disturbances directly influence musculoskeletal pain, fatigue, mood, and overall well-being.  There are limited data concerning the association between obstructive sleep apnea (OSA) and fibromyalgia (FMS). Table 2. Selected PSG variables of the total FMS sample and comparison in parameters between 2 groups. Total N=41 Group 1 N=19 Group 2 N=22 P-value Diagnostic PSG SE (%) 66.7 ± 9.7 64.5 ± 9.2 68.6 ± 9.7 0.19 WASO (min) 100 ± 32.4 110.7 ± 31.1 91.3 ± 31.4 0.059 NREM (%) 87.9 ± 13.5 90.9 ± 4.5 85.4 ± 17.8 0.2 SWS (%) 8.0 ± 5.1 7.7 ± 2.8 8.3 ± 6.5 0.69 REM (%) 9.9 ± 10.4 9.5 ± 4.1 10.4 ± 4.7 0.51 Sleep latency (min) 60.1 ± 60.9 66.1 ± 71.5 55.1 ± 51.4 0.57 REM latency (min) 237.7 ± 90.2 248.1 ± 99.4 228.8 ± 82.9 0.50 AHI 12.9 ± 17.2 24.8 ± 19.3 2.6 ± 2.2 <0.001* AI 36.2 ± 11.3 39.6 ± 10.6 33.3 ± 11.3 0.07 ODI 14.3 ± 20.4 27.9 ± 23.5 2.6 ± 2.3 Mean SaO2 (%) 94.7 ± 2.4 93.1 ± 2.4 96.1 ± 1.2 Minimum SaO2 (%) 85.1 ± 12.3 78.7 ± 15.6 90.6 ± 3.1 0.001* AIM: To assess the difference in sleep quality and functional status between FMS patients with and without OSA. METHODS:  Forty one patients were evaluated in the Sleep Disorders unit over 5 years meeting standard clinical criteria for FMS. The diagnosis of fibromyalgia was made following the fibromyalgia diagnostic criteria of the American College of Rheumatology (ARA 2010 version). All patients underwent polysomnography. The Fibromyalgia Impact Questionnaire (FIQ) assessed participants’ severity of symptoms. Depression level was assessed with Beck Depression Inventory (BDI). Subjective daytime sleepiness was assesed by Epworth sleepiness scale (ESS). Table 3. Questionnaire scores of the total FMS sample and comparison between 2 groups. Questionnaires Total N=41 Group 1 N=19 Group 2 N=22 P-value FIQ 50.9 ± 23.1 53.2 ± 21.7 48.5 ± 24.7 0.56 BDI 15.0 ± 8.1 14.2 ± 8.3 15.9 ± 8.1 0.53 ESS 11.9 ±5.1 13.3 ± 4.7 10.7 ± 5.2 0.07 RESULTS I: Nineteen out of 41 (46%) patients had an AHI greater than 10. The patients were then divided into two groups in terms of OSA presence: group 1 which included 19 FMS patients with OSA and group 2 with 22 FMS patients without OSA. RESULTS II: A statistically significant correlation was found between FIQ scores and mean SO2 (%) for all patients (r = -0.35; p = 0.048) and a statistically significant trend with sleep latency (r=0.36, p=0.07). In group 1, SE (%) (r=0.52, p=0.033) and presence of diabetes (r=0.55, p=0.023) was correlated with FIQ score. In group 2 gender (r=0.57, p=0.027) and REM (%) sleep (r=-0.55, p=0.034) were correlated with FIQ score. Table 1. Baseline demographic characteristics of the total FMS sample and comparison in parameters between 2 groups. Characteristics Total N=41 Group 1 N=19 Group 2 N=22 P-value Age (years) 51.0 ± 10.8 53.7 ± 9.5 48.7 ± 11.5 0.14 Gender, male (%) 7 (17%) 6 (44.3%) 1 (4.7%) 0.02* Menopause, n (%) 16 (39.0%) 7 (36.8%) 9 (40.9%) 0.79 BMI (kg/m2) 29.2 ± 5.9 32.5 ± 5.4 26.3 ± 4.8 <0.001* Current smokers, n (%) 10 (24.4%) 6 (31.6%) 4 (18.2%) 0.61 Comorbidities Diabetes mellitus, n (%) 8 (19.5%) 5 (26.3%) 3 (13.6%) 0.30 Hypertension, n (%) 12 (29.3%) 8 (42.1%) 0.09 Hypothyroidism, n (%) 11(26.8%) 3 (15.8%) 8 (36.4%) CONCLUSIONS: Our data suggest that there might be a relation between oxygen saturation levels and pain in FMS patients, supporting the probable effects of intermittent hypoxia resulting from OSA on functional status of these patients. The high prevalence of OSA requires more research to determine whether OSAS treatment will benefit the symptoms of FMS. REFERENCES Terzi R, Yılmaz Z, Evaluation of pain sensitivity by tender point counts and myalgic score in patients with and without obstructive sleep apnea syndrome. Int J Rheum Dis 2015;Aug 10 [Epub ahead of print] Rosenfeld VW, Rutledge DN, Stern JM, Polysomnography with quantitative EEG in patients with and without fibromyalgia, J ClinNeurophysiol, 2015,32:164-70 Roizenblatt S, Neto NS, Tufik S, Sleep disorders and fibromyalgia,Curr Pain Headache Rep 2011;15:347-57 Doufas AG, Tian L, Davies MF, Warby SC. Nocturnal intermittent hypoxia is independently associated with pain in subjects suffering from sleep-disordered breathing. Anesthesiology 2013;119:1149–62.