0866 Does Obstructive Sleep Apnea Mediate the Relationship Between Post-Traumatic Stress Disorder and Low Back Pain in Veterans?

Abstract

Introduction: Low back pain (LBP) is a common complaint among veterans, leading to notable limits in function, quality of life, and an increase in healthcare cost. The incidence and prevalence of LBP have been increasing in the veterans over the past several years. Obstructive sleep apnea (OSA) has been shown to be associated with LBP and there are notable associations among post-traumatic stress disorder (PTSD), OSA and LBP in this population. Methods: A random sample of veterans stratified by quarter was taken between 2007 and 2011 (index date), collecting records from 2006 to 2016. Veterans were excluded if they had a prevalent case of LBP, and/or OSA in the year of or year before to their index date (index period), or PTSD, OSA and/or LBP prior to the index period. Associations among the PTSD, LBP, and OSA were calculated using SAS PROC LOGISTIC. SAS PROC PHREG was used to calculate hazard ratios (HR) for mediation analysis and the percent of 4-year LBP risk explained by OSA in those with PTSD. Results: PTSD predicted LBP diagnosis (OR 1.52 [95% CI: 1.27, 1.83]) and OSA diagnosis (OR 2.06 [1.48, 2.88]). Additionally, OSA diagnosis was predictive of LBP diagnosis (OR 8.99 [95% CI: 7.07, 11.35]). The HR for the effect of PTSD on the risk LBP diagnosis was 1.47 (95% CI: 1.25, 1.74) without adjustment for OSA. The HR for the effect of PTSD on the risk LBP diagnosis adjusted for the mediator was 1.35 (95% CI: 1.15, 1.60). The resulting percent of excess LBP risk explained by OSA is 25.5% (95% CI: 19.6%,31.1%). All analyses were adjusted for potential confounders. Conclusion: OSA may mediate a significant amount of the risk of LBP diagnosis in veterans with PTSD. Prevention of OSA among veterans with PTSD may significantly reduce the risk of future LBP in veterans with PTSD.