Exploring the association between brief evaluation of psychosis symptom domains and HbA1c in patients with schizophrenia and schizoaffective disorder.

BACKGROUND: Patients with schizophrenia have an elevated burden of type 2 diabetes mellitus (T2DM), but the relationship between psychiatric symptom domains of schizophrenia and glycemic status has been less well established. This study aimed to investigate the association of clinical factors with HbA1c in this population, particularly focusing on Brief Evaluation of Psychosis Symptom Domains (BE-PSD), a symptom scale easy to use in routine clinical practice.

METHOD: This retrospective observational study included patients aged 18 years or older with schizophrenia or schizoaffective disorder admitted to the psychiatric ward of Ashikaga Red Cross Hospital between April 2021 and November 2025. A linear mixed-effects model was fitted with HbA1c as the dependent variable, clinical factors including the five BE-PSD symptom domains as fixed effects, and a random intercept for patient ID.

RESULTS: The primary analysis included 369 admissions of 249 patients. Of the 249 patients, 44 (17.7%) had a history of T2DM. Older age (p = 0.0013), higher body mass index (p = 0.028), and greater BE-PSD mania/excitement symptoms (p = 0.038) were significantly associated with higher HbA1c. Mania/excitement symptoms were not associated with HbA1c in the sensitivity analyses.

CONCLUSIONS: Older age, higher body mass index, and greater BE-PSD mania/excitement symptoms were associated with higher HbA1c, although the mania/excitement association was not statistically significant in the sensitivity analyses and should be interpreted as exploratory. Further studies are necessary to establish the relationship between symptoms of schizophrenia and glycemic status, and to examine whether BE-PSD can help characterize symptom-metabolic relationships in routine care.