Long-term traditional Chinese medicine use and incidence of metabolic syndrome in schizophrenia: a retrospective cohort study.

Objective: This study aims to assess the impact of medium-to long-term traditional Chinese medicine (TCM) combined with antipsychotic medications on metabolic syndrome (MetS) in patients with schizophrenia and to explore the prevalence and related influencing factors of MetS in these patients. Methods: A retrospective cohort study was conducted among hospitalized patients in a psychiatric hospital.We included inpatients diagnosed with schizophrenia between 1 January 2022, and 31 December 2024. Patients aged ≥18 years, with good medication adherence, and hospitalized for 6 months or more were included. Based on whether the study subjects used TCM during hospitalization, they were divided into an exposed group and a non-exposed group, and the outcomes of both groups were retrospectively tracked, specifically the occurrence of MetS. We first used univariate analysis to screen for potential confounding variables. Then, multivariate logistic regression analysis was performed to adjust for the influence of confounding factors; finally, the impact of exposure factors on the study outcomes was assessed, and odds ratios (OR) were calculated. Results: A total of 897 patients were included in this study. The average age was 47.68 years ± 14.67 years. Among them, 163 patients (18.17%) were in the TCM exposed group, and 247 patients (27.53%) had MetS. The incidence of MetS in the TCM exposed group was 17.18%, while the incidence in the non-exposed group was 29.84%. The incidence of "central obesity" (29.5% vs. 39.8%) and "hyperglycemia" (13.50% vs. 21.8%) in the TCM exposed group was lower than that in the non-exposed group respectively. Binary logistic regression results showed that educational background, TCM, quetiapine, clozapine, risperidone, aripiprazole, and BMI were independently associated with the occurrence of MetS. Compared to patients with lower educational levels (≤9 years), those with higher education (>12 years) had a reduced risk of developing MetS (OR: 0.45, 95% CI: 0.25-0.81, p < 0.01). Compared to patients not using TCM, medium-to long-term (≥6 months) use of TCM reduced the risk of MetS (OR: 0.50, 95% CI: 0.30-0.83, p < 0.01). Patients using risperidone (OR: 0.54, 95% CI: 0.36-0.83, p < 0.01) and aripiprazole (OR: 0.39, 95% CI: 0.21-0.72, p < 0.01) had relatively lower risks of MetS incidence compared to patients taking any other antipsychotic drugs. The incidence of MetS showed varying degrees of reduction. A higher BMI is positively correlated with an increased risk of MetS (OR: 1.39, 95% CI: 1.32-1.46, p < 0.001). Compared to patients not using quetiapine or clozapine, those who used quetiapine (OR: 1.86, 95% CI: 1.11-3.13, p < 0.05) or clozapine (OR: 1.74, 95% CI: 1.14 - 2.68, p < 0.05) had an increased risk of developing MetS. Conclusion: In this retrospective cohort study, the occurrence of MetS among hospitalized patients with schizophrenia was common. Exposure to quetiapine, clozapine and increased BMI were significant risk factors for MetS; while exposure to TCM, aripiprazole, risperidone, and having higher education were protective factors against the occurrence of MetS. It is necessary to detect and prevent MetS in patients with schizophrenia. Long-term TCM treatment can reduce the incidence of MetS, providing a better alternative and direction for patients with chronic schizophrenia.