Ethnic differences in albuminuria and advanced chronic kidney disease among individuals with type 2 diabetes: a retrospective cohort study in South London

Abstract

Abstract Background Chronic kidney disease (CKD) is a major complication of type 2 diabetes (T2D) and contributes to morbidity and mortality. Ethnic disparities in CKD progression are well recognised, but the role of albuminuria and other clinical risk factors in driving these differences remains unclear. Methods We examined 26 298 adults with T2D identified from primary care records in Lambeth DataNet between 2005 and 2021. The mean (SD) age was 61.2 (12.3) years, ranging from 18 to 90 years; 52.1% were males. Self-reported ethnic distribution showed 40.5% Black (n=10 651), 36.7% White (n=9656), 15.5% Asian (n=4074), 4.0% Mixed (n=1043) and 3.3% Other (n=874). Baseline demographic, clinical, biochemical and medication data were analysed. Albuminuria was classified using the urine albumin-to-creatinine ratio (ACR) as A1 (<3 mg/mmol), A2 (3–30 mg/mmol) or A3 (>30 mg/mmol). Advanced CKD was defined as stage 4–5 (estimated glomerular filtration rate (eGFR)<30 mL/min/1.73 m²). Traditional risk factors included age, sex, body mass index (BMI), glycated haemoglobin (HbA1c), blood pressure (BP), lipid profile, baseline eGFR, albuminuria and medication use. Logistic regression was used to identify predictors of advanced CKD, adjusting for these traditional risk factors, as well as ethnicity and the interaction of age and ACR. Results Albuminuria distribution varied significantly by ethnicity, with macroalbuminuria (A3) most prevalent in Mixed (25.6%; n=213) and Other ethnicities (24.6%; n=177), compared with Whites (23.2%; n=1758) and Blacks (22.4%; n=1960). In multivariable models, Asian ethnicity was independently associated with advanced CKD (adjusted OR 1.30 (95% CI 1.01 to 1.69), p=0.04) compared with White. Additional predictors included older age (OR 1.02 (95% CI 1.01 to 1.03), p<0.001), higher HbA1c (OR 1.02 (95% CI 1.01 to 1.02), p<0.001), BMI (OR 1.02 (95% CI 0.99 to 1.02), p=0.01), systolic BP (OR 1.02 (95% CI 1.01 to 1.02), p=0.003), microalbuminuria (A2) (OR 1.33 (95% CI 1.02 to 1.73)) and macroalbuminuria (A3) (OR 1.22 (95% CI 1.02 to 1.45)). Conversely, higher LDL cholesterol (OR 0.72 (95% CI 0.63 to 0.83)) and baseline eGFR (OR 0.95 (95% CI: 0.95 to 0.96)) were associated with lower risk of advanced CKD. Conclusions Asian ethnicity and modifiable risk factors, including poor glycaemic control, obesity and systolic hypertension, are key determinants of advanced CKD in people with T2D. Albuminuria A3 was most prevalent in Asian people, emphasising the need for early, proactive management and culturally tailored interventions.