C-peptide immunoreactivity index is associated with improvement of HbA1c: 2-Year follow-up of sitagliptin use in patients with type 2 diabetes. Issue 3 (June 2015)

• Record Type: Journal Article
• Authors: Nishimura, Takeshi; Meguro, Shu; Sekioka, Risa; Tanaka, Karin; Saisho, Yoshifumi; Irie, Junichiro; Tanaka, Masami; Kawai, Toshihide; Itoh, Hiroshi
• Is Part Of: Diabetes research and clinical practice. Volume 108:Issue 3(2015)
• Page Start: 441
• Page End: 447
• Publication Date: 2015-06
• Subjects: Sitagliptin -- Long-term effect -- C-peptide -- Haemoglobin A1c protein -- Human; Diabetes -- Periodicals; Diabetes Mellitus -- Periodicals; 616.462
• DOI: 10.1016/j.diabres.2015.02.031
• Languages: English
• ISSNs: 0168-8227

Abstract

Highlights: Sitagliptin decreased HbA1c, and the effect was sustained for 2 years. Sitagliptin increased CPR index, and the effect was sustained for 2 years. A greater increase in the CPR index was associated with the response to sitagliptin. Sitagliptin improved glycemic control via an improved intrinsic insulin response. Abstract: Aims: This retrospective study aimed to determine the hypoglycaemic effect of 2 years of sitagliptin administration in terms of changes in HbA1c and C-peptide immunoreactivity (CPR) index (plasma CPR [ng/mL]/glucose [mg/dL] × 100). Methods: The inclusion criteria for DPP-4 inhibitor-naive outpatients with type 2 diabetes ( n = 285) were: continuation of sitagliptin for ≥700 days from initial administration and measurement of HbA1c, serum CPR, and plasma glucose levels at 0, 3, 6, 12, 18, and 24 months after sitagliptin initiation. Logistic regression analyses determined the factors contributing to the response to sitagliptin, based on responder (ΔHbA1c ≤−0.4% [≤−4 mmol/mol]) and non-responder (ΔHbA1c >−0.4% [>−4 mmol/mol]) groups. Results: The HbA1c level decreased and CPR index increased from baseline to 3, 6, 12, 18, and 24 months after the start of sitagliptin administration (HbA1c: 7.4 ± 0.8% [57 ± 9 mmol/mol], 7.3 ± 0.9% [57 ± 9 mmol/mol], 7.4 ± 0.9% [58 ± 10 mmol/mol], 7.1 ± 0.8% [55 ± 9 mmol/mol], and 7.3 ± 0.9% [57 ± 10 mmol/mol], respectively, all P < 0.001 vs. baseline [8.0 ± 1.0%, 64 ± 11 mmol/mol] and CPR index: 1.69 ± 0.96, 1.71 ± 1.10, 1.62 ± 0.96, 1.64 ± 0.92, and 1.66 ± 0.96, respectively, all P < 0.05 vs. baseline [1.47 ± 0.81]). Higher baseline HbA1c level, shorter diabetes duration, and greater CPR index increase after sitagliptin administration were associated with the response to sitagliptin. Conclusions: Our results suggest that sitagliptin improves glycaemic control via an improved intrinsic insulin response.