A non-inferiority randomized controlled trial comparing behavioral sleep interventions in women veterans: A secondary analysis of pain outcomes

Women are disproportionally more likely to experience both insomnia and chronic pain. While these two conditions frequently co-occur, a wealth of literature suggests that insomnia is a stronger predictor of pain than pain is of insomnia. Preliminary research indicates that sleep apnea may also lead to adverse pain outcomes, with the combination of insomnia and sleep apnea contributing to an adverse synergistic effect on pain. Despite the clinical implications of such findings, knowledge regarding the interrelations between sleep disorder complexity and pain remain limited, especially among women. Additionally, interventions seeking to improve pain by targeting insomnia have yielded inconsistent results and warrant further research. Thus, the main aims of the present study were to: 1) characterize the association between sleep disorder presentations and pain in women and, 2) examine whether behavioral interventions for sleep leads to improved pain outcomes. In order to accomplish these aims, the current study analyzed data from a recently completed randomized control trial in which women veterans with insomnia were randomly assigned to receive six-weeks of either cognitive behavioral therapy for insomnia (CBT-I) or acceptance and behavioral changes for insomnia (ABC-I). Insomnia and pain were assessed at baseline, post-treatment, and at a three-month follow-up. Insomnia symptoms were primarily assessed using the Insomnia Severity Index while sleep apnea symptoms were captured using home-based sleep apnea testing. Pain symptoms were assessed using the Brief Pain Inventory. At baseline, results revealed no differences in pain among participants with varying sleep disorder presentations. Additionally, insomnia symptoms, but not AHI, were linked to worse pain outcomes. Both CBT-I and ABC-I were associated with decreased pain intensity and pain interference at post-treatment and follow-up, with results suggesting that ABC-I is equivalent to CBT-I in terms of improving pain outcomes. Improvements in pain were largely independent of pain chronicity and sleep disorder complexity. Findings suggest that behavioral interventions for insomnia might have important secondary benefits for pain in women and highlight the need to assess for pain in the context of insomnia