Study objectives: Clinical guidelines recommend cognitive-behavioral therapy for insomnia (CBT-I) as first-line treatment. However, provision of CBT-I is limited due to insufficient time and expertise. Internet-delivered CBT-I might bridge this gap. This study aimed to estimate the cost-effectiveness of guided, internet-delivered CBT-I (i-Sleep) compared to care-as-usual for insomnia patients in general practice over 26 weeks from a societal perspective.
Methods: Primary outcomes were the Insomnia Severity Index (ISI, continuous score and clinically relevant response), and Quality-Adjusted Life Years (QALYs). Societal costs were assessed at baseline, and at 8 and 26 weeks. Missing data were imputed using multiple imputation. Statistical uncertainty around cost and effect differences was estimated using bootstrapping, and presented in cost-effectiveness planes and acceptability curves.
Results: The difference in societal costs between i-Sleep and care-as-usual was not statistically significant (-€318; 95% CI -1282 to 645). Cost-effectiveness analyses revealed a 95% probability of i-Sleep being cost-effective compared to care-as-usual at ceiling ratios of €450/extra point of improvement in ISI score and €7,000/additional response to treatment, respectively. Cost-utility analysis showed a 67% probability of cost-effectiveness for i-Sleep compared to care-as-usual at a ceiling ratio of 20,000 €/QALY gained.
Conclusions: The internet-delivered intervention may be considered cost-effective for insomnia severity in comparison with care-as-usual from the societal perspective. However, the improvement in insomnia severity symptoms did not result in similar improvements in QALYs.