Nearly one in every three people with type 1 diabetes continue to produce insulin, some for decades after diagnosis, according to research published in Diabetes Care.
Residual insulin production is more likely to be present in those diagnosed in adulthood and those with shorter disease duration, according to the researchers.
“We found that the frequency of detectable residual beta-cell function in those with type 1 diabetes is more common than generally assumed,” Asa K. Davis, PhD, T1D Exchange program manager at Benaroya Research Institute at Virginia Mason, Seattle, and colleagues wrote.
The researchers measured nonfasting levels of C-peptide in 919 people with type 1 diabetes and confirmed results with a mixed-meal tolerance test in those with detectable fasting levels. C-peptide was present in 29% of the nonfasting tests (≥0.017 nmol/L; 95% CI, 26-32) and reached ≥0.2 nmol/L — a level associated with fewer complications from diabetes — in 10% (95% CI, 8-12). Researchers estimated the true frequency of C-peptide based on mixed-meal tolerance test to be 40% (95% CI, 33-46).
Presence of C-peptide was significantly associated with disease duration and age at diagnosis. In participants with type 1 diabetes for 3 to 5 years, the marker was detected in 78% of those who were diagnosed after age 18 years and in 46% of those diagnosed before age 18 years; of participants with type 1 diabetes for more than 40 years, 16% were diagnosed as adults and 6% had been diagnosed in childhood (P<.001 for all).
These data “suggest important differences in the biological process of type 1 diabetes between those diagnosed as children or as adults,” the investigators wrote.
“These findings lend further credence to research underway on targeted therapies that could prolong insulin production, helping type 1 diabetes patients better manage their disease and reduce complications,” Davis said in a press release. “For example, potential immunotherapy treatments are already being studied with this goal in mind, and our findings underscore that those diagnosed at a young age may be more likely to benefit from such new approaches.”
Disclosure: Davis reports no relevant financial disclosures. See the study for a full list of disclosures.