Effect of ramelteon on insomnia severity: evaluation of patient characteristics affecting treatment response

We conducted a multicenter, open-label, observational study to evaluate the effectiveness and safety of ramelteon in patients with insomnia, and patient characteristics affecting treatment response in routine clinical practice. Eligible patients were aged ≥ 20 years, had a diagnosis of insomnia with difficulty falling asleep, and were scheduled to receive ramelteon 8 mg/day for 12 weeks. The primary objective was to evaluate the relationship between changes in insomnia severity [measured by the Insomnia Severity Index (ISI)] and patient characteristics. Changes in the physical (PCS-8) and mental (MCS-8) components of the Short Form-8 (SF-8), and safety were also investigated. 1527 patients received therapy; 40.5% were aged ≥ 65 years and 29.7, 56.9, and 13.4% had mild, moderate, or severe insomnia, respectively. At week 12, significant improvements in ISI score [mean change (standard deviation) from baseline, − 5.0 points (6.3); p < .0001], PCS-8 score [+ 2.40 points (8.71); p < .0001], and MCS-8 score [+ 3.68 points (9.47); p < .0001] were observed. Factors affecting ISI response or remission (based on adjusted odds ratios) included age ≥ 75 years, shorter disease duration, no alcohol intake, being employed full time, not taking concomitant medication for insomnia, and taking ramelteon more than 1 h before bedtime. In total, 5.9% of patients reported adverse drug reactions. In routine clinical practice, 12 weeks’ therapy with ramelteon was effective at improving insomnia severity, with no new safety concerns identified. Several patient characteristics were found to influence response to therapy. Clinical trial identifier: UMIN000013271