Estimation of age and sex-specific Glomerular Filtration Rate and its association with mortality and atherosclerotic cardiovascular outcomes in the Abu Dhabi population; A Retrospective Cohort Study.

Background: The impact of reduced kidney function quantified by estimated Glomerular Filtration Rate (eGFR) on various adverse clinical outcomes has been extensively studied. This study aims to estimate the age and sex-specific eGFR in the Abu Dhabi population and its association with adverse outcomes.

Methods: This is a retrospective cohort study conducted in 8699 participants enrolled in a national cardiovascular disease screening program from 2011 to 2013. A reference eGFR percentile was estimated from healthy cohort members who had no comorbidities. The  LMS (Lambda, Mu, and Sigma) method was used to determine these percentiles. The cohort was reassessed in 2023 for mortality and cardiovascular outcomes.

Results: The reference percentiles of normal eGFR values showed a marked decrease with age, with small sex differences in the reference percentile distribution. Subjects in the two categories within the higher eGFR threshold range, the 95th and 97th percentiles were older, had a significantly higher prevalence of diabetes, were more frequently smokers, and had higher body mass index, higher HbA1c, higher HDL, lower vitamin D, and were more likely to be males, with higher physical activity and a lower prevalence of coronary heart disease. Older age, female sex, history of atherosclerotic cardiovascular disease, history of hypertension, being treated for hypertension, lower diastolic blood pressure, higher systolic blood pressure, lower HDL, higher HbA1c, and higher vitamin D were significantly associated with lower eGFR percentiles.

Conclusions: These ethnicity-specific eGFR reference values are valuable for the early identification of patients with chronic kidney disease, allowing for early qualification for beneficial preventive medication, evaluations, and nephrologist referrals. A prognostic definition of the higher eGFR threshold, as renal hyperfiltration, is suggested since the 97th percentile had a significantly higher incidence of atherosclerotic cardiovascular disease.