title: Factors Contributing to the Clinical Effectiveness of the DPP-4 Inhibitor Sitagliptin in Patients With Type 2 Diabetes.
abstract: OBJECTIVE
  Treatment with dipeptidyl peptidase 4 (DPP-4) inhibitors may have responders or nonresponders. However, agreement on the effects of patient background and/or contributory factors that have a negative effect on the efficacy of DPP-4 inhibitors is lacking. The aim of the present study was to investigate the effect of resistance factors on the clinical efficacy of sitagliptin (SITA) for patients with type 2 diabetes.
  
  
  METHODS
  We performed a retrospective study based on the medical records of patients who were treated with SITA alone (SITA-A; n = 16), a combination of a sulfonylurea (SU) without a change in dose and add-on SITA (SU + SITA; n = 29), SITA alone after the discontinuation of premedication with antidiabetic agents (SITA-AD; n = 18), or a combination of an SU with a dose reduction and SITA (L-SU + SITA; n = 17). Multivariate logistic regression analysis was employed to estimate the influence of resistance factors on hemoglobin (Hb) A1c lowering by SITA treatment for 3 months.
  
  
  RESULTS
  The HbA1c levels were significantly lower after 3-month treatment with SITA-A (6.3% [0.2%]), SU + SITA (7.1% [0.2%]), and L-SU + SITA (6.6% [0.2%]), but not with SITA-AD (6.3% [0.2%]), than baseline levels before treatment. Multivariate logistic regression analysis established that a decreased efficacy of SITA was markedly related to baseline HbA1c levels of ≥7.5% and dyslipidemia.
  
  
  CONCLUSIONS
  These results suggest that checking for the presence or absence of resistance factors, including elevated HbA1c levels and dyslipidemia, may contribute to the appropriate usage of SITA.
authors.affiliation: Department of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Takatori
authors.affiliation: Department of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Japan.
authors.forename: Yukina
authors.initials: Y
authors.lastname: Hamada
authors.affiliation: Division of Pharmacy, Ehime University Hospital, Shitsukawa, Japan. Electronic address: akiki@m.ehime-u.ac.jp.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tanaka
authors.affiliation: Department of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Akiyama
authors.affiliation: Department of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Namba
authors.affiliation: Division of Pharmacy, Ehime University Hospital, Shitsukawa, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Japan.
authors.forename: Hiromu
authors.initials: H
authors.lastname: Kawasaki
authors.affiliation: Division of Pharmacy, Ehime University Hospital, Shitsukawa, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Araki
mesh_terms: D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000627:therapeutic use; D005260:Female; D006442:Glycated Hemoglobin / Q000187:drug effects; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D000068900:Sitagliptin Phosphate / Q000627:therapeutic use*; D013453:Sulfonylurea Compounds / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D054873:Dipeptidyl-Peptidase IV Inhibitors; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D000068900:Sitagliptin Phosphate; D013453:Sulfonylurea Compounds
keywords: DPP-4 inhibitors; sitagliptin; sulfonylureas; type 2 diabetes mellitus