Long-term benefits of digital cognitive behavioural therapy for insomnia: Follow-up report from a randomized clinical trial.

Digital cognitive behavioural therapy (dCBT) is an effective treatment for chronic insomnia and also improves well-being and quality of life (QoL). We assessed whether these benefits are sustained and if the effects of dCBT extend to the use of sleep medication and healthcare. In total 1,711 adults (48.0 ± 13.8 years, 77.6% female) with complaints of chronic insomnia participated in a previously published randomized controlled trial (ISRCTN 60530898) comparing dCBT (n = 853) with sleep hygiene education (SHE, n = 858). At weeks 0, 4, 8, 24, 36 and 48, we assessed functional health (Patient-Reported Outcomes Measurement Information System: Global Health Scale); psychological well-being (Warwick-Edinburgh Mental Well-being Scale) and sleep-related QoL (Glasgow Sleep Impact Index), prescribed and non-prescribed sleep medication use, and healthcare utilization. At week 25, those who received SHE at baseline were offered dCBT. dCBT improved functional health (difference: 2.45, 95% confidence interval [CI]: 2.03; 2.88, Cohen's d: 0.50, p < .001), psychological well-being (difference: 4.34, 95% CI: 3.70; 4.98, Cohen's d: 0.55, p < .001) and sleep-related QoL (difference: -44.61, 95%CI: -47.17; -42.05, Cohen's d: -1.44, p < .001) at week 48 compared to baseline. At week 24 dCBT, compared to SHE, also reduced use of prescription and non-prescription sleep medication up to week 24 (adjusted rate ratio [RR]: 0.64, 95% CI: 0.42; 0.97, p = .037 and adjusted RR: 0.52, 95% CI: 0.37; 0.74, p < .0001, respectively), but not healthcare utilization. Uncontrolled follow-up suggests that these effects were sustained for non-prescribed sleep medication (RR: 0.52, 95% CI: 0.40; 0.67, p < .001). In conclusion, this study suggests that dCBT results in sustained benefits to insomnia and its daytime outcomes.