0462 Hypertension Status Moderates Insomnia and Atrophy of the Left Superior Frontal Gyrus Interaction in Women with Fibromyalgia

Abstract Introduction The left superior frontal gyrus (L-SFG) is integral to higher-level cognition. Poor sleep decreases L-SFG connectivity with other brain regions and impairs cognitive performance. Conversely, atrophy of L-SFG can contribute to insomnia. Hypertension (HTN) raises the risk of insomnia and L-SFG atrophy. People with chronic pain are susceptible to insomnia, HTN, and brain atrophy, but their complex interaction remains unclear. We explore how HTN status influences the relationship between insomnia and the integrity of L-SFG in individuals with chronic pain. Methods Baseline data from female adults (N=27) diagnosed with fibromyalgia and chronic insomnia underwent a one-night ambulatory polysomnography (PSG; Comet-PLUS Portable, Natus Neurology) to record sleep and assess the presence of any sleep disorders as part of a RCT (R01AR055160 and R01AR055160-S1; NCT02001077). Anatomical scans were obtained for all participants. Participants reported hypertension status (Y/N). Moderation analysis with SPSS Process Macro was used to examine relationships between PSG total awakenings (frequency), L-SFG, and hypertension status (moderator). Results Moderation analysis showed a significant interaction between total awakenings and hypertension status (B=0.04, SE=0.01, t=2.44, p=0.02), indicating hypertension status significantly influences the relationship between total awakenings and the integrity of L-SFG. The link between total awakenings and L-SFG was negative and significant among participants without hypertension (B=-0.04, SE=0.08, t=-4.62, p=0.0001), but not significant among those with hypertension (B=-0.003, SE=0.01, t=-0.24, p=0.81). This suggests individuals without hypertension experienced greater atrophy in L-SFG as awakenings increased. The overall model explained 48.66% of variance in L-SFG (F[3,23] = 7.27, p=0.0013). Conclusion Frequent awakening in women experiencing pain can impair cognition and contribute to brain deterioration, even with fewer cerebrovascular conditions. The findings highlight the importance of preventive measures before conditions like hypertension and insomnia develop. Longitudinal studies and reviews of hypertension management and lifestyle differences could provide additional insights into these results. Support (if any) R01AR055160 and R01AR055160-SI; PI McCrae