Factors Associated With Physical Restraints in a Psychiatric Unit in Japan: a Retrospective Study.

Objective: To identify factors associated with the use and duration of physical restraint (PR) in a psychiatric unit in Japan.

Methods: Medical records of 1308 patients admitted first time to the psychiatric emergency unit of Showa University Northern Yokohama Hospital between 1 January 2014 and 31 December 2021 were retrospectively reviewed. Data collected included patient age, sex, outpatient treatment, living arrangements, disability pension status, diagnosis (based on ICD-10), and psychotropic medication use at admission (chlorpromazine equivalent dose, imipramine equivalent dose, diazepam equivalent dose, and number of mood stabilisers administered). Logistic regression analysis and multiple regression analysis were used to identify factors associated with the use and duration of PR, respectively.

Results: Of 1308 patients, 399 (30.5%) were subjected to PR and 909 (69.5%) were not. Among the 399 patients subjected to PR, 54 were excluded from the multiple regression analysis for duration of PR as they remained subject to PR on the day of discharge. The remaining 345 patients were subject to PR for a median of 10 days. PR utilisation was associated with male sex (odds ratio [OR] = 1.420), treatment at our hospital (OR = 0.260), treatment at other hospitals (OR = 0.645), F3 diagnosis (depression) [OR = 0.290], F4-9 diagnosis (OR = 0.309), and imipramine equivalent dose at admission (unit OR = 0.994). The log-transformed duration of PR was independently associated with the age group of 50 to 69 years (β = 0.248), the age group of ≥70 years (β = 0.274), receiving a disability pension (β = 0.153), an F1 diagnosis (β = -0.187), an F4-9 diagnosis (β = -0.182), chlorpromazine equivalent dose at admission (β = 0.0004), and number of mood stabilisers administered at admission (β = -0.270).

Conclusion: Identifying factors associated with the use and duration of PR may lead to reduction in the use and duration of PR.