Adults with type 2 diabetes and major depressive disorders who begin using second-generation antipsychotics are more likely to have at least a 10% decline in oral antidiabetic drug use 180 to 365 days after initiation compared with nonusers of second-generation antipsychotics, according to a study.

Todd A. Lee, PharmD, PhD, of the department of pharmacy systems, outcomes and policy at the College of Pharmacy, University of Illinois at Chicago, and colleagues evaluated data from the 2009 to 2015 MarketScan Commercial Claims and Encounters database on adults (median age, 54 years) with previously treated type 2 diabetes and major depressive disorders who were new users of second-generation antipsychotics or non-second-generation antipsychotics to determine adherence and persistence to oral antidiabetic drugs between them.

The odds of at least a 10% decline in oral antidiabetic drug adherence during 180 and 365 days and time to oral antidiabetic discontinuation were evaluated using multivariate regression models. In the main analysis, 8,664 adults (21.5% second-generation antipsychotic users) were included in the 180-day analysis and 8,311 (22.1% second-generation antipsychotic users) were included in the 365-day analysis; a persistence cohort (n = 17,524; 21.3% second-generation antipsychotic users) was also included and allowed for 45-, 60- and 90-day gaps in medication use.

The index date was the date of the first dispensing of the cohort drug and follow-up was conducted until first occurrence of discontinuation of oral antidiabetic drug, switch or addition of a medication from the alternative drug class, any gap in insurance coverage or end of the study period (Dec. 31, 2015).

In the 180 days before and after the index date, 16.6% of second-generation antipsychotic users and 13.3% of non-second-generation antipsychotic users had at least a 10% decline in oral antidiabetic drug adherence. After 365 days, compared with non-second-generation antipsychotic users, more second-generation antipsychotic users were nonadherent (30.6% vs. 33.4%; P = .025) or had at least a 10% decline in oral antidiabetic drug adherence (18.9% vs. 22.3%; P = .001).

The odds of having a 10% decline in oral antidiabetic drug adherence was higher in second-generation antipsychotic users compared with nonusers during 180 days (adjusted OR = 1.41; 95% CI, 1.21-1.63) and 365 days (adjusted OR = 1.34; 95% CI, 1.17-1.53), after adjustment for age, sex, depression and diabetes severity, polypharmacy, pill burden, days’ supply of last oral antidiabetic drug prescriptions filled pre-index, adjunctive vs. monotherapy and baseline adherence to oral antidiabetic drugs.

“The reasons, predictors and clinical implications for the decline in [oral antidiabetic drug] adherence in both groups deserve further study,” the researchers wrote. “For physicians treating patients with depression and diabetes, close monitoring of [oral antidiabetic drug] adherence may be warranted, particularly in patients’ initiating a [second-generation antipsychotic].” – by Amber Cox