Recent trends in the characteristics of patients prescribed sitagliptin and other oral antihyperglycaemic agents in a large U.S. claims database.

Aim: This study was designed to determine if differences in baseline characteristics of patients with type 2 diabetes mellitus (T2DM) being treated with sitagliptin vs. other oral antihyperglycaemic agents (OAHA) during the initial 2 years following sitagliptin's introduction in the U.S. continued during the second 2 years of sitagliptin availability.

Methods: Patients with T2DM and at least one new prescription for sitagliptin or another OAHA from Oct 2006 to April 2010 were identified in an insurance claims database. Multivariate logistic regression adjusting for age, gender, treatment type (monotherapy, dual or triple therapy), new or existing T2DM diagnosis, and comorbidities and diabetes complications in the prior 12 months was used to estimate odds ratios for sitagliptin vs. other OAHAs.

Results: During 2006-2007 or 2008-2010, new sitagliptin users were older and more likely to be male, have prior diagnosis of T2DM, or initiating combination therapy compared with new users of other OAHAs. Prevalence of comorbidities and complications was consistently higher for new sitagliptin users across most of the conditions assessed during both time periods.

Conclusions: New sitagliptin users consistently tended to be older and have greater comorbidity/complication burden compared with new users of other OAHAs. These differences in baseline characteristics persisted up to 4 years postapproval. This observation has significant implications for observational studies using electronic medical record or insurance claims databases. Appropriate adjustment is needed to try to control for potential confounding and channelling bias resulting from this non-random prescribing pattern, and the limitations of such analyses acknowledged.