Factors influencing length of hospital stay among psychiatric inpatients in Montreal, Canada: The role of insulin, IL-6 and TNF-Alpha

Hospital length of stay (LOS) is a widely used indicator of healthcare efficiency and a key metric for evaluating the performance of psychiatric services. This study aims to identify predisposing, needs-related, and enabling factors associated with LOS among patients with psychiatric disorders admitted through the psychiatric emergency room in Montreal, Canada. A total of 600 individuals with mental health disorders who were hospitalized between 2012 and 2018 were interviewed. Guided by the Behavioral Model for Vulnerable Populations, factors influencing LOS were assessed using a negative binomial regression model. Longer LOS was associated with patients aged 60 and older, those diagnosed with psychotic and/or personality disorders at admission, individuals with elevated interleukin-6 (IL-6) levels (a pro- and anti-inflammatory cytokine), and those with a history of hospitalization. In contrast, shorter LOS was observed among patients with common mental health symptoms, substance use disorders (SUD), suicidal ideation, among those with elevated levels of the pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) or insulin. Targeted interventions such as Assertive Community Treatment for patients with personality disorders, intensive home care for those with psychotic disorders, and crisis resolution teams for individuals experiencing suicidal ideation or common mental health symptoms may help reduce hospitalization durations. For patients with SUD, improved referral systems and harm reduction–oriented outpatient care are recommended. Circulating biomarkers such as IL-6, TNF-α, and insulin may aid in early identification of patients at risk for prolonged stays and hold promise for integration into clinical decision-making and treatment. Further research is needed to validate these findings across diverse psychiatric populations.