Predictors of Veterans Health Administration utilization and pain persistence among soldiers treated for postdeployment chronic pain in the Military Health System

BACKGROUND: Chronic pain presents a significant burden for both federal health care systems designed to serve combat Veterans in the United States (i.e., the Military Health System [MHS] and Veterans Health Administration [VHA]), yet there have been few studies of Veterans with chronic pain that have integrated data from both systems of care. This study examined 1) health care utilization in VHA as an enrollee (i.e., linkage to VHA) after military separation among soldiers with postdeployment chronic pain identified in the MHS, and predictors of linkage, and 2) persistence of chronic pain among those utilizing the VHA. METHODS: Observational, longitudinal study of soldiers returning from a deployment in support of the Afghanistan/Iraq conflicts in fiscal years 2008–2014. The analytic sample included 138,206 active duty soldiers for whom linkage to VHA was determined through FY2019. A Cox proportional hazards model was estimated to examine the effects of demographic characteristics, military history, and MHS clinical characteristics on time to linkage to VHA after separation from the military. Among the subpopulation of soldiers who linked to VHA, we described whether they met criteria for chronic pain in the VHA and pain management treatments received during the first year in VHA. RESULTS: The majority (79%) of soldiers within the chronic pain cohort linked to VHA after military separation. Significant predictors of VHA linkage included: VHA utilization as a non-enrollee prior to military separation, separating for disability, mental health comorbidities, and being non-Hispanic Black or Hispanic. Soldiers that separated because of misconduct were less likely to link than other soldiers. Soldiers who received nonpharmacological treatments, opioids/tramadol, or mental health treatment in the MHS linked earlier to VHA than soldiers who did not receive these treatments. Among those who enrolled in VHA, during the first year after linking to the VHA, 49.7% of soldiers met criteria for persistent chronic pain in VHA. CONCLUSIONS: The vast majority of soldiers identified with chronic pain in the MHS utilized care within VHA after military separation. Careful coordination of pain management approaches across the MHS and VHA is required to optimize care for soldiers with chronic pain. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12913-021-06536-8.