Contribution of cardiometabolic risk factors to estimated glomerular filtration rate decline in Indigenous Australians with and without albuminuria - the eGFR Follow-up Study

Aim: We assessed associations between cardiometabolic risk factors and estimated glomerular filtration rate (eGFR) decline according to baseline albuminuria to identify potential treatment targets in Indigenous Australians. Methods: The eGFR Follow-up Study is a longitudinal cohort of 520 Indigenous Australians. Linear regression was used to estimate associations between baseline cardiometabolic risk factors and annual Chronic Kidney Disease Epidemiology Collaboration eGFR change (mL/min per 1.73m²/year), among those classified with baseline normoalbuminuria (urine albumin-to-creatinine ratio (uACR) <3 mg/mmol; n = 297), microalbuminuria (uACR 3–30 mg/mmol; n = 114) and macroalbuminuria (uACR ≥30 mg/mmol; n = 109). Results: After a median of 3 years follow-up, progressive declines of the age- and sex-adjusted mean eGFR were observed across albuminuria categories (−2.0 [−2.6 to –1.4], −2.5 [−3.7 to −1.3] and −6.3 [−7.8 to −4.9] mL/min per 1.72m²/year). Although a borderline association was observed between greater baseline haemoglobin A_1c and eGFR decline in those with macroalbuminuria (P = 0.059), relationships were not significant in those with microalbuminuria (P = 0.187) or normoalbuminuria (P = 0.23). Greater baseline blood pressure, C-reactive protein, waist-to-hip ratio and lower high-density lipoprotein cholesterol showed non-significant trends with greater eGFR decline in the presence of albuminuria. Conclusion: Over a 3 year period, marked eGFR decline was observed with greater baseline albuminuria. Cardiometabolic risk factors were not strong predictors for eGFR decline in Indigenous Australians without albuminuria. Longer follow-up may elucidate the role of these predictors and other mechanisms in chronic kidney disease progression in this population.