The type rather than the daily dose or number of antipsychotics affects the incidence of hyperglycemic progression.

There have been concerns that antipsychotics increase the incidence of hyperglycemic progression. Many factors have been suggested to contribute to the risk of antipsychotic-induced hyperglycemic progression, including the type, daily dose, and number of antipsychotics; however, few studies have examined these relationships. This study aimed to examine the affect of antipsychotic treatment-associated factors on hyperglycemic progression, after adjustment for the affect of background factors suggested to be associated with hyperglycemic progression. This was a nationwide, multicenter, prospective cohort study examining the incidence of hyperglycemic progression during a 12 mo period following the initiation of newly prescribed antipsychotic medication. Demographic data, medication history, and blood test values were collected from 631 study participants with normal blood glucose levels at baseline for 12 mo. The primary endpoint (incidence of hyperglycemic progression) was defined as progression from normal to prediabetic or probable diabetic status, and was evaluated based on the Japanese monitoring guidance in patients with schizophrenia. To further examine the affect of antipsychotics on glucose metabolism over time, we examined changes in HbA1c levels 3, 6, and 12 mo after the initiation of treatment with each antipsychotic. We found that treatment with zotepine and clozapine was associated with a significantly high incidence of hyperglycemic progression. Furthermore, changes in HbA1c levels 6 mo after the initiation of zotepine treatment were significantly higher than those following blonanserin and haloperidol treatments. In contrast, there was no significant difference in the change in total cholesterol, triglycerides, HDL cholesterol, and BMI during the same period. Moreover, the "daily dose" and "number" of antipsychotics did not show an association with the incidence of hyperglycemic progression. However, in a post hoc analysis in which the antipsychotics were divided into two groups according to the strength of blockade of H1, M1, M3, and 5-HT2C receptors, the incidence of hyperglycemic progression was higher in the medium- and high-daily dose groups than in the low-daily dose group in the antipsychotic group with strong blockade of these receptors. Our study indicated that the type of antipsychotic had a greater affect on the incidence of hyperglycemic progression than the daily dose of antipsychotics or their number. Among these, zotepine was most likely to increase the incidence of hyperglycemic progression, suggesting the need for caution when these antipsychotics are prescribed.