title: Characterization of Sitagliptin Use in Patients with Type 2 Diabetes and Chronic Kidney Disease by Cross-Sectional Analysis of a Medical Insurance Claims Database.
abstract: BACKGROUND
  Chronic kidney disease (CKD) is common in patients with type 2 diabetes (T2DM) and makes them particularly susceptible to safety/tolerability issues related to many classes of oral antihyperglycemic agents (OAHA). Dipeptidyl peptidase-4 inhibitors (DPP-4is) like sitagliptin are generally well tolerated in patients with T2DM and renal disease and therefore may be preferentially used in patients with CKD. To assess the extent of this preference, the characteristics of sitagliptin users with T2DM and CKD were compared with those of other (non-DPP-4i) OAHA users with T2DM and CKD.
  
  
  METHODS
  Patients with T2DM and CKD with claims between 2006 and 2012 were identified from a United States insurance claims database. Patients starting sitagliptin or another OAHA as mono, dual, or triple therapy were compared. Demographic and clinical characteristics within 5 years before starting or escalating to new therapies were assessed.
  
  
  RESULTS
  Compared to patients with CKD starting other OAHAs, patients with CKD starting sitagliptin as mono or dual therapy were older, had more physician visits, were more likely to have a history of heart failure and to use loop diuretics. In triple therapy patients, the differences between groups were not as pronounced, but the overall prevalences of comorbidities was higher.
  
  
  CONCLUSIONS
  Similar to prior observations in a general T2DM population, patients with T2DM and CKD prescribed sitagliptin tend to be older and have more comorbidities than those prescribed other classes of OAHA. If not recognized and analyzed appropriately, this channeling could lead to biased treatment effect estimates in comparative analyses that include users of sitagliptin.
  
  
  BACKGROUND
  Merck & Co., Inc., Kenilworth, NJ, USA.
authors.affiliation: Merck, Kenilworth, NJ, USA.|Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT, USA.
authors.forename: Kimberly G
authors.initials: KG
authors.lastname: Brodovicz
authors.affiliation: Merck, Kenilworth, NJ, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Merck, Kenilworth, NJ, USA.
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Merck, Kenilworth, NJ, USA.|Procter & Gamble, Cincinnati, OH, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Ritchey
authors.affiliation: Merck, Kenilworth, NJ, USA.
authors.forename: Jane
authors.initials: J
authors.lastname: Liao
authors.affiliation: Merck, Kenilworth, NJ, USA. samuel_engel@merck.com.
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Engel
keywords: Channeling bias; Chronic kidney disease; Observational study; Oral antihyperglycemic agents; Treatment outcomes; Type 2 diabetes