Cognitive status moderates long‐term benefits of non‐pharmacological insomnia therapy in older adults: A secondary analysis of a randomized clinical trial

INTRODUCTION: This secondary analysis examined whether mild cognitive impairment (MCI) moderates the effectiveness of non-pharmacological insomnia therapy and whether insomnia therapy is associated with clinically meaningful symptom reduction. METHODS: Cognitively intact (CI; n = 87) and MCI (n = 38) older adults with insomnia completed insomnia therapy. The primary outcome was the Insomnia Severity Index (ISI), assessed at baseline, post-treatment, and 6-month follow-up (6FU). Linear mixed effects models evaluated ISI changes across time and group. Logistic regression examined clinically meaningful reductions (ISI decrease ≥ 6). RESULTS: Both groups showed significant ISI reductions at post-treatment and 6FU (p-values < 0.0001). There were no between-group differences at post-treatment (p = 0.869). Yet, at 6FU, CI participants, compared to MCI, showed significantly greater symptom reduction (p = 0.036), and a higher proportion achieved clinically meaningful reduction in ISI (78.7% vs. 45.8%). DISCUSSION: Older adults with MCI benefit from insomnia therapy; however, their continued symptom reduction 6-months later may be dampened compared to CI older adults. CLINICAL TRIAL REGISTRATION INFORMATION: Treatments for Insomnia: Mediators, Moderators and Quality of Life ClinicalTrials.gov, NCT02117388.