The role of sex and ethnicity in the variability of estimated glomerular filtration rate (eGFR) in people with type 1 diabetes

AIMS: To examine sex-based differences in estimated glomerular filtration rate (eGFR) trajectories for people with type 1 diabetes (T1D) over 10 years and to test the hypothesis that sex and ethnicity interaction predicts eGFR decline. METHODS: A cohort of 1495 individuals, 48% men (81% White, 12% African-Caribbean and 7% Other) and baseline eGFR ≥45 mL/min/1.73 m² was analysed. Group-based trajectory modelling (GBTM) was used to identify eGFR sex-specific trajectories, and linear mixed models were used to evaluate the role of sex and ethnicity interaction in predicting eGFR heterogeneity. RESULTS: Five eGFR trajectories were identified in both women and men. Rapid decline (>3 mL/min/1.73 m²/year) occurred in 5.75% of women and 10% of men. Among women, the group included 12.3% of the African-Caribbean and 4.8% of the White; among men, it included 24.3% of the African-Caribbean, 22.2% of the Asian and 8.3% of the White. Mild/Stable decline was observed in 16% of women and 27% of men. Mean eGFR was lower by (-20 [95% CI -25, -15] mL/min/1.73 m²/year) in African-Caribbean women and (-15 [-21, -9]) in men, compared to White women and men respectively. The lowest eGFR sex gap observed in African-Caribbeans, and the highest in 'Other'. CONCLUSIONS: Interactions between sex and ethnicity may determine the heterogeneity in kidney function decline.