New Classification System Would Improve Prediction of ESRD

Adding information on urinary albumin to estimated glomerular filtration rate (eGFR) would be more accurate in identifying patients at risk of progression to ESRD, suggests a study in the Journal of the American Society of Nephrology.

Analysis of nearly 66,000 participants from a Norwegian population-based health study identified 124 subjects who progressed to ESRD over 10.5 years’ follow-up. Multivariate analyses were performed to determine how well the combination of baseline eGFR and urine albumin predicted progression to ESRD. Other potential renal risk factors were also evaluated for their independent predictive value.

Both eGFR and urine albumin were strong independent predictors of progression to ESRD. Hazard ratios associated with eGFR increased from 6.7 at 45–59 mL/min/1.73 m2, to 18.8 at 30 to 44 mL/min/1.73 m2, to 65.7 at 15–29 mL/min/1.73 m2. Hazard ratios for microalbuminuria and macroalbuminuria were 13.0 and 47.2, respectively. Information on hypertension, diabetes, smoking, obesity, and a range of other factors offered no additional predictive value.

At the current eGFR threshold (15 to 59 mL/min/1.73 m2), 4.7 percent of the study population would have been referred, resulting in identification of 69.4 percent of participants expected to progress to ESRD. With addition of information on urinary albumin, only 1.4 percent of the population would be referred, while still detecting 65.6 percent of those expected to progress to ESRD.

Adding urinary albumin to eGFR would improve the ability to identify patients likely to progress to ESRD. Classification systems combining these two variables will provide a “simple and powerful tool” for risk assessment in CKD, the researchers believe [Hallan SI, Ritz E, Lydersen S, Romundstad S, Kvenild K, Orth SR: Combining GFR and albuminuria to classify CKD improves prediction of ESRD. J Am Soc Nephrol 2009; 1069–1077].