Albuminuria emerges as key predictor of chronic kidney disease progression: Landmark cohort study unveils critical findings

The study, published in the Annals of Internal Medicine, revealed that patients with CKD and normoalbuminuria (<30 mg/g) had an excess risk for CKD progression, which increased linearly with higher albuminuria levels.

Chronic kidney disease, a global public health concern affecting millions worldwide, is characterized by a gradual decline in renal function over time. While albuminuria, the presence of albumin in urine, has long been recognized as a hallmark of kidney damage, its precise role in disease progression has remained a subject of intense scrutiny.

Albuminuria is a major risk factor for CKD progression, especially when categorized as moderate (30 to 300 mg/g) or severe (>300 mg/g). However, data is limited on the prognostic value of albuminuria within the normoalbuminuric range (<30 mg/g) in patients with CKD. Ashish Verma, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, and colleagues aimed to estimate the increase in the cumulative incidence of CKD progression with greater baseline albuminuria levels among CKD patients who had normoalbuminuria (<30 mg/g).

For this purpose, the researchers conducted a multicenter prospective cohort study at 7 U.S. clinical centers. It included 1629 participants meeting criteria from the CRIC (Chronic Renal Insufficiency Cohort) study with CKD (estimated glomerular filtration rate [eGFR], 20 to 70 mL/min/1.73 m2) and urine albumin–creatinine ratio (UACR) less than 30 mg/g.

Baseline spot urine albumin divided by spot urine creatinine to UACR calculation as the exposure variable. The 10-year adjusted cumulative CKD progression incidences from confounder-adjusted survival curves were determined using the G-formula. CKD progression is defined as a composite of 50% eGFR decline or kidney failure (dialysis or kidney transplantation).

The researchers reported the following findings:

• Over a median follow-up of 9.8 years, 182 of 1629 participants experienced CKD progression.
• The 10-year adjusted cumulative incidences of CKD progression were 8.7%, 11.5%, and 19.5% for UACR levels of 0 to less than 5 mg/g, 5 to less than 15 mg/g, and 15 mg/g or more, respectively.
• Comparing persons with UACR 15 mg/g or more to those with UACR 5 to less than 15 mg/g and 0 to less than 5 mg/g, the absolute risk differences were 7.9% and 10.7%, respectively.
• The 10-year adjusted cumulative incidence increased linearly based on baseline UACR levels.

In the study involving patients with chronic kidney disease, those with urine albumin levels on the higher side of normal had a greater disease progression risk compared to those with lower urine albumin.

"Patients with higher albuminuria also had a greater incidence of overt kidney failure than their lower albuminuria counterparts," the researchers wrote.

The main limitation of the study was that the UACR was measured once.

Reference:

Verma A, Schmidt IM, Claudel S, Palsson R, Waikar SS, Srivastava A. Association of Albuminuria With Chronic Kidney Disease Progression in Persons With Chronic Kidney Disease and Normoalbuminuria : A Cohort Study. Ann Intern Med. 2024 Apr;177(4):467-475. doi: 10.7326/M23-2814. Epub 2024 Apr 2. PMID: 38560911.