title: Factor Analysis of Changes in Hemoglobin A1c After 12 Months of Sitagliptin Therapy in Patients With Type 2 Diabetes.
abstract: BACKGROUND
  Sitagliptin, a dipeptidyl peptidase-4 inhibitor, is an effective oral antidiabetic agent as both monotherapy and when combined with insulin. Data from three observational studies performed in patients with type 2 diabetes receiving sitagliptin therapy in the routine clinical setting were integrated to conduct factor analysis of the changes in hemoglobin A1c (HbA1c), body weight, and estimated glomerular filtration rate (eGFR) over 12 months.
  
  
  METHODS
  Among patients with type 2 diabetes attending medical institutions affiliated with Kanagawa Physicians Association, those using sitagliptin were followed for 1 year. In the ASSET-K and ASSIST-K studies, patients were managed by diabetologists, while they were managed by non-diabetologists in the ATTEST-K study. Patients were not administered insulin in ASSET-K, whereas insulin was administered in ASSIST-K. HbA1c (National Glycohemoglobin Standardization Program), blood glucose (fasting/postprandial), body weight, and renal function (serum creatinine and eGFR) were the efficacy endpoints. Factor analysis was performed by analysis of variance using the magnitude of the change in HbA1c, body weight, and eGFR after 12 months of sitagliptin therapy as response variables, and the study, sex, and age as explanatory variables.
  
  
  RESULTS
  Of 1,327 patients registered in ASSET-K (diabetologists/without insulin), 1,167 patients in ASSIST-K (diabetologists/with insulin), and 530 patients in ATTEST-K (non-diabetologists), statistical analysis was carried out on 1,074, 854, and 411 patients, respectively. There were significant inter-study differences in patient characteristics (complications, duration of diabetes, and baseline HbA1c), the sitagliptin dose, and the use of other antidiabetic agents. HbA1c decreased significantly in all three studies. According to factor analysis, the magnitude of the change in HbA1c over 12 months showed significant inter-study differences and was also significantly influenced by the age, duration of diabetes, and baseline HbA1c.
  
  
  CONCLUSIONS
  Comparison of three observational studies identified differences in patient characteristics, treatment of diabetes (use/non-use of insulin), and the level of specialist care (diabetologist/non-diabetologist). Despite such differences, consistent reduction of HbA1c by sitagliptin was demonstrated in all three studies. The patients showing most improvement in HbA1c with sitagliptin therapy were older patients with a short duration of diabetes and high baseline HbA1c level.
authors.affiliation: Study Group of the Hypertension Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Shouhei
authors.initials: S
authors.lastname: Yuasa
authors.affiliation: Study Group of the Hypertension Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Sato
authors.affiliation: Study Group of the Diabetes Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Takai
authors.affiliation: Study Group of the Diabetes Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Ishikawa
authors.affiliation: Study Group of the Diabetes Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Umezawa
authors.affiliation: Study Group of the Diabetes Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kubota
authors.affiliation: Study Group of the Diabetes Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Maeda
authors.affiliation: Study Group of the Diabetes Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kanamori
authors.affiliation: Study Group of the Hypertension Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Miyakawa
authors.affiliation: Division of Metabolism and Endocrinology, Department of Internal Medicine, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Endocrinology and Diabetes, Yokohama City University Medical Center, Kanagawa, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Terauchi
authors.affiliation: Study Group of the Diabetes Committee, Kanagawa Physicians Association, Kanagawa, Japan.
authors.forename: Ikuro
authors.initials: I
authors.lastname: Matsuba
keywords: Body weight; DPP-4 inhibitor; Estimated glomerular filtration rate; Hemoglobin A1c; Sitagliptin; Type 2 diabetes