Inpatient phase-advance therapy for delayed sleep–wake phase disorder: a retrospective study

PURPOSE: The efficacy of inpatient phase-advance therapy among patients with delayed sleep–wake phase disorder (DSWPD) has not been adequately investigated because response rates are considered low. We aimed to examine the efficacy of such treatment in this patient population. PATIENTS AND METHODS: The present retrospective study included data from 66 patients with DSWPD who had been admitted to Akita University Hospital for inpatient phase-advance therapy between September 1, 2005, and April 30, 2018. DSWPD was diagnosed based on the International Classification of Sleep Disorders, 3rd edition, criteria using electronic medical records. We examined remission rates during inpatient therapy as well as relapse rates at the time of the first outpatient examination following discharge. Univariate analysis was performed to investigate predictive factors for postinpatient therapy relapse. RESULTS: The rate of DSWPD remission over the course of inpatient phase-advance therapy was 100% (95% CI: 95.6%–100%), with a median duration of 1 day (IQR: 1–2 days; range: 1–9 days) until remission. The rate of relapse following discharge was 45.8% (95% CI: 32.7%–59.2%). Univariate analysis indicated that the rate of relapse was significantly higher for minors (under 18) than adults (18 and over), for those whose age at onset was below 16 years than for those whose age at onset was 16 or above, and for those with relatively low motivation for their occupation (P=0.0339, P=0.0136, and P<0.001, respectively). CONCLUSION: The rate of DSWPD remission under inpatient phase-advance therapy was remarkably high (100%), while the rate of relapse after discharge was ~50%. Further studies are required to determine the long-term prognosis of inpatient therapy, risk factors for relapse, and the types of treatment most effective for preventing relapse.