Objective This study was to explore the influence of antipsychotic (APS) therapy on sugar metabolism, and its relationship
to the abnormal
glycosylated hemoglobin.Methods After the glycosylated hemoglobin (HbA_1c) was determined, 152 patients with
schizophrenia were divided into normal or abnormal HbA_1c group, and then were randomly given risperidone, clozapine or chlorpromazine treatment for 6 weeks. The fasting plasma glucose (FPG) and 2-hour plasma glucose in oral glucose tolerance test (2HPG) was measured at baseline and after treatment .Results Although no significant difference between baseline and after treatment in the FPG was found in all patients, the 2HPG was increased from <(7.2±1.4) mmol/L> at baseline to <(9.5±1.8) mmol/L> after clozapine therapy (P<0.01). In patients with abnormal HbA_1c, the 2HPG after treatment was higher in clozapine <(9.5±1.8) mmol/L> than that in risperidone <(7.4±1.7) mmol/L> and chlorpromazine <(7.3±1.6) mmol/L> group (P<0.01), but in patients with normal HbA_1c, no significant difference was found between the three APS group (P>0.05). The 2HPG were <(7.1±1.6) mmol/L> at baseline and <(8.1±1.9) mmol/L> after treatment in patients with abnormal HbA_1c, which were significantly higher than that <(6.2±1.4) mmol/L and (6.5±1.4) mmol/L, respectively> in patients with normal HbA_1c. The patients with abnormal HbA_1c were at higher risk of developing ASP-induced sugar metabolism than those with normal HbA_1c (standard OR=9.5).Conclusion The results indicate that schizophrenic patients with abnormal HbA_1c are likely to develop antipsychotic-induced sugar metabolism disease.