Timely outpatient follow-up and readmission risk in schizophrenia.

Timely outpatient follow-up after psychiatric hospitalization has been proposed as a key strategy to reduce readmission; however, evidence in patients with first-admission schizophrenia remains limited. Using the Korean National Health Insurance Claims Database, we conducted a nationwide retrospective cohort study of 1,961 patients with first-admission schizophrenia, defined as having no psychiatric service utilization during the preceding three years. We examined whether outpatient follow-up within 30 days after discharge was associated with the risk of readmission within 365 days. Adjusted Cox proportional hazards models were used to estimate hazard ratios across multiple cumulative follow-up periods (60, 90, 120, 150, 180, and 365 days), controlling for sociodemographic and clinical factors. Kaplan-Meier analysis was used to assess differences in readmission-free survival. Among the study population, 53.2% received outpatient follow-up within 30 days after discharge. When evaluated across progressively longer cumulative follow-up periods, outpatient follow-up was associated with a significantly lower risk of readmission at 60 days (aHR = 0.52, 95% CI: 0.29-0.95), 90 days (aHR = 0.55, 95% CI: 0.35-0.88), 120 days (aHR = 0.63, 95% CI: 0.43-0.94), 150 days (aHR = 0.66, 95% CI: 0.46-0.95), and 180 days (aHR = 0.70, 95% CI: 0.51-0.98), but not at 365 days (aHR = 0.79, 95% CI: 0.61-1.02). Kaplan-Meier analysis showed longer readmission-free survival in the follow-up group, although the difference was more pronounced over shorter follow-up durations. Timely outpatient follow-up was associated with reduced readmission risk over shorter cumulative follow-up periods, with attenuation of the association as the follow-up duration increased.