Beta-cell function and its trajectories in a multi-ethnic population with type 2 diabetes: a hospital-based retrospective cohort study

ABSTRACT Background. In high-income regions such as Europe, people of non-European origin have a higher prevalence of type 2 diabetes (T2DM), poorer glycaemic control, and more complications than people of European origin. Emerging evidence suggests lower beta-cell function at diagnosis in people of non-European origin, possibly due to more adverse early-life conditions that may impair pancreatic development and function, but whether beta-cell function also declines faster is unknown. Without timely insulin initiation, faster decline may worsen glycaemic control. We therefore assessed beta-cell function over time in a multi-ethnic population with T2DM. Methods. This retrospective cohort study used electronic health records of adults with T2DM at Amsterdam UMC (2014-2025). Because C-peptide is not measured routinely, only 456 people had a measurement and 125 had repeated measurements, so analyses were exploratory. Fasting (≥8 hours) C-peptide was compared between people of Dutch and Surinamese origin (mainly African and South Asian ancestry), the only groups with adequate data, and trajectories were plotted as smoothed curves. Findings. C-peptide was lower in people of Surinamese than of Dutch origin (difference −0.20 nmol/L, 95% CI −0.37 to −0.03). Over up to 10 years, C-peptide appeared to decline more rapidly in people of Surinamese origin (difference at 10 years −0.14 nmol/L, 95% CI −0.29 to 0.01). Interpretation. Beta-cell function, and possibly beta-cell decline, may differ by origin in T2DM. If confirmed in larger studies, matching treatment to early beta-cell failure could help improve glycaemic control in some groups of non-European origin.