Uehara R, Yamada E, Nakajima Y, Osaki A, Okada S, Yamada M. Casual C peptide index: Predicting the subsequent need for insulin therapy in outpatients with type 2 diabetes under primary care.
J Diabetes 2022;
14:221-227. [PMID:
35229479 PMCID:
PMC9060140 DOI:
10.1111/1753-0407.13257]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 01/04/2022] [Accepted: 01/26/2022] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND
Evaluation of residual beta cell function is indispensable in patients with type 2 diabetes as it informs not only diagnoses but also appropriate treatment modalities. However, there is a lack of convenient biomarkers for residual beta cell function. Therefore, we evaluated endogenous insulin level as a biomarker in outpatients who were being treated with insulin therapy and in patients who were introduced to insulin therapy after 4 years.
METHODS
Data of 174 outpatients with type 2 diabetes (50% male) whose glycemia was moderately controlled (glycated A1c 7.3% [5.2%-14.8%]) were reviewed. Twenty patients whose estimated glomerular filtration rate was lower than 30 ml/min/1.73 m2 were excluded from the evaluation of endogenous insulin level with both casual C-peptide index (C-CPI) and urinary C-peptide/creatinine ratio (determined at any time, generally 1-2 h after breakfast). Patients were stratified based on the provision of insulin therapy.
RESULTS
C-CPI and UCPCR were significantly lower in the insulin-treated patients than in the insulin-untreated patients (0.9 vs. 2.2, p < 0.0001; 24.7 vs. 75.5, p = 0.0003, respectively). Moreover, C-CPI were significantly lower in the insulin-requiring patients for 4 years than in the insulin-unrequiring patients (1.0 vs. 1.7, p = 0.0184). The multivariate logistic regression analysis revealed that both indicators of insulin secretion influenced the requirement for insulin therapy, but C-CPI could serve as the most convenient and useful biomarker for not only current insulin therapy requirements (p = 0.0002) but also the subsequent requirement for insulin therapy (p = 0.0008).
CONCLUSIONS
C-CPI could be determined easily, and it was found to be a more practical marker for outpatients; therefore, our findings would have critical implications for primary care.
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