TIMELAPSE study-efficacy of low-dose amitriptyline versus cognitive behavioral therapy for chronic insomnia in patients with medical comorbidity: study protocol of a randomized controlled multicenter non-inferiority trial.

Background: Insomnia is common in people with long-term medical conditions and is related to increased mortality and morbidity. Cognitive behavioral therapy for insomnia (CBT-I) is first choice treatment and effective for people with insomnia and comorbid long-term medical conditions. However, CBT-I has some limitations as it might not always be available or appeal to patients with medical conditions. Furthermore, a small proportion of patients do not respond to CBT-I. Preliminary evidence and clinical experience suggest that low-dose amitriptyline (AM) might be an effective alternative to treat insomnia in patients with medical comorbidity. In this randomized controlled trial, we will determine whether AM is non-inferior to the first choice treatment for insomnia, CBT-I.

Methods/design: This study will test if treatment with low-dose amitriptyline for insomnia in patients with medical comorbidity is non-inferior to CBT-I in a multicenter randomized controlled non-inferiority trial. Participants will be 190 adults with a long-term medical condition and insomnia. Participants will be randomly allocated to one of two intervention arms: 12 weeks AM (starting with 10 mg per day, and if ineffective at 3 weeks, doubling this dose) or 12 weeks of CBT-I consisting of 6 weekly sessions and a follow-up session 6 weeks later. The primary outcome is subjective insomnia severity, measured with the Insomnia Severity Index (ISI). The primary endpoint is at 12 weeks. Secondary outcomes include sleep quality (e.g., sleep efficiency), questionnaires on daytime functioning (physical functioning and impairment of functioning), and symptoms (e.g., fatigue, pain, anxiety) at 12 weeks and 12 months post treatment and relapse of insomnia until 12 months after treatment.

Discussion: Irrespective of the outcome, this study will be a much-needed contribution to evidence based clinical guidelines on the treatment of insomnia in patients with medical comorbidity.

Trial Registration: Dutch Trial Register NTR NL7971 . Registered on 18 August 2019.