Prevalence and Predictors of Rapid Estimated Glomerular Filtration Rate Decline in Patients with Non-albuminuric Diabetic Kidney Disease: A Single-centre Retrospective Cohort Study

Background: Non-albuminuric diabetic kidney disease (NADKD) is increasingly recognised and strongly associated with heightened cardiovascular risk and rapid decline in estimated glomerular filtration rate (eGFR). Aims: This single-centre retrospective cohort study aimed to determine the prevalence of NADKD, characterise clinical and laboratory features, assess microvascular and macrovascular complication rates and identify predictors of rapid progression. Materials and Methods: This retrospective cohort study analysed 44 NADKD patients from January 2018 to 2022, excluding chronic kidney disease stage 5, albuminuric DKD and <6 months of follow-up. The primary outcome was the prevalence and profile of rapid progressors (eGFR fall of >5 mL/min/1.73 m²/year) in NADKD and secondary outcomes were the onset of microvascular and macrovascular complications and risk factors for rapid progression. Results: The median 1-year follow-up showed rapid eGFR drop in 36.4% of patients, with a median yearly decline of 8.0 mL/min/1.73 m²/year (Interquartile range [IQR]: 6.2–12.1) compared to 1.0 mL/min/1.73 m²/year (IQR: 0.5–1.8) in non-progressors (P < 0.001). Presence of hypertension (P = 0.04), cardiovascular disease (CVD) (P = 0.03), dyslipidaemia (P = 0.02) and acute kidney injury (AKI) incidents (P = 0.01), as well as the incidence of diabetic retinopathy (P = 0.01) and CVD (P = 0.04), were reported to be higher in rapid progressors. Rapid eGFR reduction was independently predicted by hypertension (Odds ratio [OR] 1.9, 95% confidence interval [CI]: 1.5–4.8), CVD (OR 2.8, 95% CI: 1.8–4.7, P = 0.01) in multivariate analysis. Conclusion: One-third of NADKD were rapid progressors, and the prevalence of hypertension, dyslipidaemia, CVD, AKI episodes and incidence of diabetic retinopathy was higher in rapid progressors. Hypertension and CVD were found to be strong predictors for rapid eGFR decline.