Ethnic differences in CKD progression among people with type 2 diabetes

Understanding the factors that drive variability in progression patterns of chronic kidney disease (CKD) is essential to optimise patient outcomes. People with type 2 diabetes who develop CKD show heterogenous patterns of progression to advanced stages of CKD. 

Differences in observed rates of eGFR decline highlight disparities across ethnic groups, but variations in study methods mean that evidence is fragmented. To provide a better understanding of the factors driving CKD progression in people with type 2 diabetes, Alobaid and colleagues examined eGFR trajectories in a large, ethnically diverse cohort.

Data, including demographic and clinical variables, were analysed from 14,489 adults with type 2 diabetes drawn from outpatient clinics in South London between 2004 and 2018 (median follow-up was 4 years). Inclusion criteria included having a baseline eGFR of ≥45 mL/min/1.73 m².

The ethnically diverse cohort was 45% White, 37.8% Black, 9.1% Asian, 2.7% Mixed and 5.2% Other ethnicities. The group-based trajectory modelling (GBTM) approach was used to investigate eGFR progression patterns, and multinomial logistic regression models assessed CKD progression to stages 4 and 5 among those with faster eGFR decline (≥1.92 mL/min/1.73 m²).

For each ethnicity, four distinct eGFR trajectories were identified, highlighting different patterns of kidney function decline: Trajectory 1 – low eGFR/steep decline; Trajectory 2 – low eGFR/stable; Trajectory 3 – moderate eGFR/stable; and Trajectory 4 – high eGFR/stable.

The 2531 participants of all ethnicities in the Trajectory 1 group tended to be older, have higher urinary albumin-to-creatinine ratios (ACR) and lower baseline eGFR. Of these, 944 (37.7%) progressed to stage 4 CKD and 368 (14.5%) to stage 5 CKD. 

After adjusting for additional risk factors, there were no differences in the risk of reaching stage 4 CKD across ethnicities, except for “Other ethnicities”, who had a significantly higher risk compared to White participants (Relative Risk Ratio [RRR], 2.23 [95% CI, 1.39 to 3.35]). In contrast, significant differences were observed in the progression to CKD stage 5 between ethnicities. The RRRs for progression compared to White individuals were 1.64 (1.22 to 2.21) for Black, 2.39 (1.57 to 3.64) for Asian, 1.97 (1.11 to 3.50) for Mixed and 3.72 (2.11 to 6.57) for Other ethnicities. 

Diabetic retinopathy (DR) stages at baseline varied across ethnic groups. The White group had the lowest prevalence of severe eye disease, while the relative risk for Asian and Other ethnicities was significantly higher. The link between the role of advanced DR stages (R2M0, R2M1, R3MO and R3M1) and faster eGFR declines was especially strong in these groups.

By highlighting which ethnic groups experienced the most rapid decline in kidney function, this study provides a better understanding of CKD risk disparities within multiethnic populations. DR may act as an early marker of rapid renal deterioration in high-risk ethnic groups, as microvascular damage pathways are shared. Tailored prevention and intervention strategies are needed to address disparities in CKD outcomes.

The full article can be read here.