The Predictive Ability of C-Peptide in Distinguishing Type 1 Diabetes From Type 2 Diabetes: A Systematic Review and Meta-Analysis
Abstract
Objective This systematic review and meta-analysis aimed to investigate the predictive ability of plasma connecting peptide (C-peptide) levels in discriminating type 1 diabetes (T1D) from type 2 diabetes (T2D) and to inform evidence-based guidelines in diabetes classification. Methods We conducted a holistic review and meta-analysis using PubMed, MEDLINE, EMBASE, and Scopus. The citations were screened from 1942 to 2021. The quality criteria and the preferred reporting items for systematic reviews and meta-analysis checklist were applied. The protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42022355088). Results A total of 23,658 abstracts were screened and 46 full texts reviewed. Of the 46 articles screened, 12 articles were included for the meta-analysis. Included studies varied by race, age, time, and proportion of individuals. The main outcome measure in all studies was C-peptide levels. A significant association was reported between C-peptide levels and the classification and diagnosis of diabetes. Furthermore, lower concentrations and the cutoff of 2 value (98.8%) affirmed the variability in effect estimates was due to heterogeneity rather than sampling error among all selected studies. Conclusion Plasma C-peptide levels are highly associated and predictive of the accurate classification and diagnosis of diabetes types. A plasma C-peptide cutoff of ≤0.20 mmol/L is indicative of T1D and of ≥0.30 mmol/L in the fastin…
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A 2023 systematic review and meta-analysis suggested a fasting or random plasma level of C-peptide of ≤0.20 mmol/l was supportive of type 1 diabetes mellitus and a level of ≥0.30 mmol/l was suggestive of type 2 diabetes mellitus.
“A 2023 systematic review and meta-analysis suggested a fasting or random plasma level of C-peptide of ≤0.20 mmol/l was supportive of T1DM and a level of ≥0.30 mmol/l was suggestive of T2DM31.”
From The epidemiology of type 1 diabetes mellitus in older adults (2025) · cites this paper as [31]
Cites
Global Prevalence of Diabetic Retinopathy and Projection of Burden through 2045
Teo, Z. L., Tham, Y.-C., Yu, M., Chee, M. L., Rim, T. H., Cheung, N., Bikbov, M. M., Wang, Y. X., Tang, Y., Lu, Y., et al. (2021) · Ophthalmology · doi:10.1016/j.ophtha.2021.04.027 · Cited by 2,420 · see citing works
The Global Epidemiology of Diabetes and Kidney Disease
Koye, D. N., Magliano, D. J., Nelson, R. G., & Pavkov, M. E. (2018) · Advances in Chronic Kidney Disease · doi:10.1053/j.ackd.2017.10.011 · Cited by 686 · see citing works
Outpatient Insulin Therapy in Type 1 and Type 2 Diabetes Mellitus: Scientific Review
DeWitt, D. E., & Hirsch, I. B. (2003) · JAMA · doi:10.1001/jama.289.17.2254 · Cited by 502 · see citing works
Combination therapies with insulin in type 2 diabetes
Yki-Järvinen, H. (2001) · Diabetes Care · doi:10.2337/diacare.24.4.758 · Cited by 300 · see citing works
De Lusignan, S., Khunti, K., Belsey, J., Hattersley, A., Van Vlymen, J., Gallagher, H., Millett, C., Hague, N. J., Tomson, C., Harris, K., et al. (2010) · Diabetic Medicine · doi:10.1111/j.1464-5491.2009.02917.x · Cited by 122 · see citing works
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The epidemiology of type 1 diabetes mellitus in older adults
Tomic, D., Harding, J. L., Jenkins, A. J., Shaw, J. E., & Magliano, D. J. (2025) · Nature Reviews Endocrinology · doi:10.1038/s41574-024-01046-z · Cited by 58 · see citing works
“A 2023 systematic review and meta-analysis suggested a fasting or random plasma level of C-peptide of ≤0.20 mmol/l was supportive of T1DM and a level of ≥0.30 mmol/l was suggestive of T2DM 31 .”
Influential
- Authors
- Iqbal, S., Jayyab, A. A., Alrashdi, A. M., & Reverté-Villarroya, S.
- Affiliations
- Liwa University (AE)
- Corresponding author
- Iqbal, Sajid
- ORCID
- Iqbal, Sajid
- Venue
- Endocrine Practice
- Publisher
- Elsevier BV
- Published
- 2023-05
- Volume
- 29
- Issue
- 5
- Pages
- 379-387
- ISSN
- 1530-891X (ISSN-L)
- OpenAlex
- W4315644429
- Cited by
- 27
- References
- 5
- Citations by year
- 2026: 6 · 2025: 12 · 2024: 8 · 2023: 1
- FWCI
- 1.04
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Endocrine Practice (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Universitat Rovira i Virgili
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Diabetes and associated disorders
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes Management and Research
- Health Sciences › Medicine › Surgery › Pancreatic function and diabetes
- Keywords
- C-peptide, type 1 diabetes, type 2 diabetes, diabetes classification, diagnostic biomarkers, fasting C-peptide, diagnostic accuracy
- MeSH terms
- C-Peptide, Diabetes Mellitus, Type 1, Diabetes Mellitus, Type 2, Humans
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