Misclassification of type 1 diabetes as type 2 diabetes in adults: practical guidance for screening and diagnosis for primary care providers.
Level 5 - mechanism / opinion, no new human data
Narrative review and clinical guidance based on expert opinion and case studies.
PubMed 42152488 · doi:10.1080/00325481.2026.2672192
What was done
The authors conducted a narrative clinical review using case studies to outline screening and diagnostic guidance for adult-onset type 1 diabetes (T1D) in primary care. The review discusses clinical identifying features and the use and limitations of confirmatory testing, including islet autoantibodies and C-peptide assays.
What was found
No quantitative diagnostic metrics, odds ratios, or trial data were reported in the abstract. The authors state that over half of all T1D cases are diagnosed in adulthood and are frequently misclassified as type 2 diabetes. Clinical features indicating potential T1D in adults include personal or family history of autoimmunity, absence of metabolic syndrome features (such as excess abdominal adiposity), and poor glycemic response to non-insulin antihyperglycemic agents leading to insulin requirement within a few years.
Why it matters
Misclassifying adult-onset T1D as type 2 diabetes leads to delayed insulin treatment and increases the risk of acute, life-threatening complications such as diabetic ketoacidosis. Practical guidance helps primary care providers identify atypical patients and order appropriate confirmatory serological tests.
Limits
This is a narrative review with illustrative case examples rather than a systematic review or prospective diagnostic accuracy study. The abstract provides no primary human subject data, sample sizes, or quantitative performance metrics (such as sensitivity, specificity, or predictive values) for the recommended diagnostic tests.
Cited by
- supports Type 1 diabetes is an autoimmune disease that is not always present from birth and can be acquired later in life.