Albuminuria not only predicts chronic kidney disease (CKD) progression, it is also a “strong and unique indicator” of CKD regression, a new study finds. Investigators suggest that albuminuria is more reliable than using estimated glomerular filtration rate (eGFR) alone.
Investigators defined albuminuria categories according to urinary albumin to creatinine ratio (UACR): A1 (UACR less than 3 mg/mmoL), A2 (UACR, 3-29 mg/mmoL), A3<60 (UACR, 30-59 mg/mmoL), and A3≥60 (UACR, 60 mg/mmoL or more).
Among 58,004 adults with moderate to severe CKD (ie, a sustained eGFR of 15-44 mL/min/1.73 m2), 61% had A1, 27% had A2, 3% had A3<60, and 10% had A3≥60 at baseline.
The 5-year probability of CKD regression was highest with albuminuria category A1 (22.6%), followed by A2 (16.5%), A3<60 (11.6%), and A3≥60 (5.3%), Pietro Ravani, MD, PhD, of the University of Calgary in Alberta, Canada, and colleagues reported in JAMA Network Open. The likelihood of CKD regression was a significant 25%, 53%, and 73% lower for the A2, A3<60, and A3≥60 groups, respectively, compared with the A1 group. These results were independent of eGFR and age. The investigators defined CKD regression as an increase in eGFR of 25% or more from baseline and sustained improvement of CKD stage, using 2 measures separated by more than 90 days.
In the A1 group, CKD regression was more likely than progression or kidney failure, Dr Ravani and his collaborators reported. They noted that patients younger than 80 years were more likely to experience CKD regression than die.
“The degree of albuminuria could be used to inform referral practices by incorporating probability of CKD progression and regression,” according to Dr Ravani’s team.
For example, among patients with stage 3b CKD, those with a UACR less than 3 mg/mmoL might be monitored in primary care, they suggested, whereas those with a UACR of 30-59 mg/mmoL may benefit from earlier nephrology referral.
Among the study’s limitations, the investigators could not assess albuminuria and weight changes over time. They also could not rule out acute kidney injury.
It remains unclear whether reducing albuminuria with drug therapy will affect CKD regression rates.
Pasternak M, Liu P, Quinn R, et al. Association of albuminuria and regression of chronic kidney disease in adults with newly diagnosed moderate to severe chronic kidney disease. JAMA Netw Open. Published online August 1, 2022. doi:10.1001/jamanetworkopen.2022.25821