SESSION TITLE: Tuesday Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM PURPOSE: Obstructive Sleep apnea (OSA) is typically characterized by excessive daytime sleepiness. Insomnia is characterized by hyperarousal, and is seen as a predominant feature in a subgroup of patients with OSA. The aim of this study was to describe the prevalence of a obstructive sleep apnea insomnia overlap (OSAIO) phenotype and characteristize its features. METHODS: This was a chart review of patients who underwent overnight polysomnogram at our sleep center. OSA was defined as an AHI >5. Patients were administered a questionnaire that included Epworth sleepiness score (ESS), detailed symptoms of insomnia as well as questions related to restless legs syndrome (RLS), nocturnal reflux. Insomnia was identified with 3 major criteria - sleep onset insomnia, sleep maintenance insomnia, and early morning awakening. Psychophysiologic insomnia (Psy-I) was defined as self-report of at least 2 of the following 5 symptoms: racing thoughts when trying to sleep, increased muscle tension when trying to sleep, fear of being unable to sleep, fear of being unable to fall back asleep after waking up, and laying in bed worrying. OSAIO was defined as presence of all 3 major insomnia criteria or 2 major criteria plus presence of Psy-I. RESULTS: A total of 296 patients were included146 Male and 150 Female. There was a high percentage of patients with at least one insomnia symptom 57% sleep onset insomnia, 68% sleep maintenance insomnia, and 48% patients early morning awakenings. 50% patients had at least 2 symptoms of Psy-I. OSAIO was present in 148 patients (50%). We found no difference in age, BMI or gender distribution between patients with and without OSAIO. OSA severity was not different between the 2 groups. AHI in OSAIO was 48 +/- 38 (vs 45 +/- 36; p 0.434) and time spent with SaO2 < 90% was 29 +/- 27 min in OSAIO (vs 29 +/- 26 min; p 0.967) Interestingly, patients with OSAIO had more daytime sleepiness – mean ESS in OSAIO was 14.2 +/- 5 (vs 12.7 +/- 6 p 0.002) and only 14% of OSAIO had ESS <8 (vs 29%; p 0.002). Patients with OSAIO had more self-reported RLS (44% with OSAOI vs 19%; p 0.001) & nocturnal reflux (42% with OSAOI vs 29%; p 0.029) 88% patients in the OSAIO had Psy-I (vs 13% without OSAIO). CONCLUSIONS: We describe a phenotype of sleep apnea and insomnia overlap OSAIO which is seen in as much as 50% of patients with OSA. No gender bias was seen in this phenotype. Patients with OSAIO have more daytime sleepiness for the same severity of OSA, as well as more self reported RLS in the OSAIO group. This suggests that the OSAIO phenotype may be more prone to the sleep disruption caused by OSA and to developing heightened cortical arousal maladaptive neurobehavioral patterns CLINICAL IMPLICATIONS: Clinicians treating patients with OSA should be aware of OSAIO phenotype. These patients tend to have more neurobehavioral morbidity related to sleep disruption, which may have implications on therapeutic domains for OSA. DISCLOSURES: No relevant relationships by Akshar Aiyer, source=Web Response No relevant relationships by Ishan Aiyer, source=Web Response No relevant relationships by Humayun Anjum, source=Web Response No relevant relationships by Sean Hesselbacher, source=Web Response Speaker/Speaker's Bureau relationship with Astra Zaneca, Sunovian, Paratek Please note: $1001 - $5000 Added 01/13/2019 by Salim Surani, source=Web Response, value=Consulting fee