Purpose: Cancer-related insomnia is associated with diminished quality of life (QOL), suggesting that improvement in insomnia may improve QOL in cancer survivors. Cognitive behavioral therapy for insomnia (CBT-I) has been shown to improve insomnia, but less is known regarding its effect on QOL and whether improvement in insomnia corresponds to improved QOL. The present analysis examines the effects of CBT-I, with and without armodafinil, on QOL both directly and indirectly through improvements of insomnia.
Methods: This is an analysis of 95 cancer survivors for a specified secondary aim of a four-arm randomized controlled trial assessing the combined and individual effects of CBT-I and armodafinil to improve insomnia. QOL and insomnia severity were assessed before, during the intervention, at post-intervention, and 3 months later by Functional Assessment of Cancer Therapy-General and Insomnia Severity Index, respectively.
Results: Mean change in QOL from pre- to post-intervention for CBT-I + placebo, CBT-I + armodafinil, armodafinil, and placebo was 9.6 (SE = 1.8; p < 0.0001), 11.6 (SE = 1.8; p < 0.0001), -0.2 (SE = 3.2; p = 0.964), and 3.3 (SE = 2.0; p = 0.124), respectively. ANCOVA controlling for pre-intervention scores showed that participants receiving CBT-I had significantly improved QOL at post-intervention compared to those not receiving CBT-I (p < 0.0001, effect size = 0.57), with benefits being maintained at the 3-month follow-up. Path analysis revealed that this improvement in QOL was due to improvement in insomnia severity (p = 0.002), and Pearson correlations showed that changes in QOL from pre- to post-intervention were significantly associated with concurrent changes in insomnia severity (r = -0.56; p < 0.0001). Armodafinil had no effect on QOL for those who did or did not receive it (p = 0.976; effect size = -0.004).
Conclusion: In cancer survivors with insomnia, CBT-I resulted in clinically significant improvement in QOL via improvement in insomnia. This improvement in QOL remained stable even 3 months after completing CBT-I.
Implications for cancer survivors: Considering the high prevalence of insomnia and its detrimental impact on QOL in cancer survivors and the effectiveness of CBT-I in alleviating insomnia, it is important that evidence-based non-pharmacological sleep interventions such as CBT-I be provided as an integral part of cancer care.
Keywords: CBT-I; Cancer; Cancer survivors; Insomnia; Quality of life.