Kidney function decline is associated with mortality events: over a decade of follow-up from Tehran Lipid and Glucose...

To investigate the association between estimated glomerular filtration rate (eGFR) change and mortality risk in a cohort from the Middle East and North Africa region with increasing chronic kidney disease burden.

We included 2210 participants aged ≥ 50 years from the prospective cohort of the Tehran Lipid and Glucose Study. The interval for eGFR measurement was between the examinations in 2002-2005 to 2009-2011, and participants were followed through March 2018. Glomerular filtration rate was estimated from serum creatinine using the CKD-EPI creatinine equation. We assessed the association of rapid kidney function decline, (defined as annual eGFR decline ≥ 3 ml/min/1.73 m² per year); ≥ 30% eGFR decline over six years; and certain drop in kidney function (≥ 25% eGFR decline plus drop in eGFR category) with mortality outcomes.

During a median follow-up of 14.3 years after recruitment, 315 all-cause and 112 cardiovascular disease deaths were recorded. The multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of all-cause death for rapid kidney function decline, ≥ 30% decline in eGFR over 6 years, and drop in kidney function were 1.68 (1.24-2.27), 2.01 (1.46-2.78), and 1.49 (1.11-1.98), respectively. The HRs of all-cause death and for rapid kidney function decline in those without and with chronic kidney disease were 1.41 (1.03-1.91) and 3.38 (1.69-6.76), respectively. Similar findings were observed regarding cardiovascular disease-related and non-cardiovascular disease-related mortality.

Estimated GFR decline is associated with an increased mortality risk, indicating its ability to provide additional prognostic information beyond traditional risk predictors in the general population.