Predicting the Risk of Rehospitalization in Patients with Paranoid Schizophrenia Considering Disease Duration and Maintenance Antipsychotic Therapy

Background: the search for predictors of readmission applicable in real clinical practice is still of interest to schizophrenia researchers. The prognostic value of antipsychotic therapy after discharge from the hospital and its relationship to the duration of the disease remain poorly understood. The aim was to identify risk factors for repeated hospitalization in patients with paranoid schizophrenia, taking into account the duration of the disease and the underlying antipsychotic therapy prescribed at the time of discharge from a psychiatric hospital. Patients and Methods: the study included 163 patients with paranoid schizophrenia (unselected sampling; women — 42.3% (n = 69), average age — 30.26 ± 7.05 years), discharged after inpatient treatment. Antipsychotic therapy was taken into account when the patient was discharged from the hospital, according to medical records for the period from 2018 to 2024. Antipsychotic drugs were divided into the first and second generations (respectively, FGA and SGA). Patients taking clozapine were excluded from the study. The method of taking the medicine (oral or injectable in the form of a depot) was taken into account. All doses of the drugs have been converted to standard daily doses (the equivalent of 5 mg of risperidone according to the WHO Defined daily dose method). The prognostic significance of the duration of the disease was also studied. The risk of re-hospitalization was assessed using the Cox regression method with mixed effects. Results: mean duration of follow-up was 3.87 [2.87; 4.08] years. The average dosage of the antipsychotic was 1.20 [0.99; 1.67] daily doses. Secondgeneration antipsychotics accounted for 76.2% in total structure of drug prescriptions. The share of extended forms of both generations accounted for 18.1% of appointments. With one SGA hospitalization, the risk of repeated hospitalization decreases with an increase in the standard dose (aHR = 0.24 (0.07; 0.83), p = 0.005). In the first episode, the overall risk of rehospitalization was lower relative to that of chronic patients (aHR = 0.49 (0.29, 0.82), p < 0.001). For the remaining combinations of factors “drug dose — antipsychotic generation — number of hospitalizations”, the trends are not unambiguous. Conclusions: the risk of rehospitalization at the first psychotic episode was reduced by 2.04 (1.22; 3.40) times regardless of the therapy received. When patients are prescribed SGA drugs (except clozapine) in a dose exceeding the standard daily dose, the risk of rehospitalization decreases by 4.17 (1.20; 14.29) times regardless of the duration of the disease.

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