The Study in Outpatient Medicine using Nudges to Improve Sleep (SOMNUS): study protocol for an 18-month factorial, cluster-randomized trial to increase guideline-concordant treatment of insomnia in primary care.

BACKGROUND: Guidelines support cognitive behavioral therapy for insomnia (CBT-I) as the first-line treatment for chronic insomnia. However, the most widely prescribed treatments are pharmacological sedatives referred to as "Z-drugs," which are not recommended as first-line or for long-term use. The Study in Outpatient Medicine Using Nudges to Improve Sleep (SOMNUS) is an 18-month, factorial, cluster-randomized trial designed to evaluate the effectiveness of behavioral interventions that nudge primary care clinicians to provide guideline-concordant treatment for patients with insomnia by facilitating CBT-I use and discouraging Z-drug orders. METHODS: The SOMNUS trial takes place at Northwestern Medicine, an academic health system located in and around Chicago, IL, USA, and will enroll 444 primary care clinicians working in 64 outpatient clinics. Using a 2 × 2 factorial design, clinicians will be clinic-cluster-randomized to receive one of two nudges embedded in the electronic health record (EHR), their combination, or neither. The first nudge sets the default dispense quantity for new Z-drug orders to 10 pills with no refills. The second nudge is a just-in-time prompt with a one-click option to align orders with guidelines and requires clinicians to enter a justification if prompt recommendations are not followed. The primary outcome is the change in encounter-level Z-drug pill count from the 18 months before through the 18 months after the intervention period begins. Secondary outcomes will assess CBT-I referrals, monthly Z-drug pill count, Z-drug treatment duration, and benzodiazepine pill count. DISCUSSION: The SOMNUS trial will use EHR-integrated behavioral nudges that aim to increase guideline-concordant treatment of insomnia in primary care. Results can inform scalable approaches to improve insomnia treatment. TRIAL REGISTRATION: ClinicalTrials.gov NCT06640023. Prospectively Registered on October 15 2024.