Nephrosclerosis patients without diabetes and low levels of proteinuria may have rapid kidney function decline: Study

The study found a greater risk than initially predicted of rapid kidney function decline in nephrosclerosis without diabetes (NS-DM) patients with low proteinuria levels.

There is no clarity on whether the effect of proteinuria on rapid kidney function decline is equivalent among non-DKD with diabetes (NDKD+DM), diabetic kidney disease (DKD), and nephrosclerosis without diabetes, particularly in patients with advanced chronic kidney disease (CKD). To clarify the same, Tomohito Gohda, Juntendo University Faculty of Medicine, Bunkyo-ku, Tokyo, Japan, and colleagues conducted a post hoc analysis using BRIGHTEN study data to compare the eGFR slope and the rapid kidney function decline prevalence, in addition to kidney and cardiovascular (CV) outcomes, in Japanese CKD patients among these three CKD categories.

The study included 1038 CKD patients who participated in the BRIGHTEN study. A linear mixed-effect model was applied to estimate each disease group's annual glomerular filtration rate (eGFR) decline.

The following were the key findings of the study:

• The prevalence of rapid decliners (rapid kidney function decline, defined as an eGFR loss of > 5 mL/min/1.73 m2/year) in the DKD group (44.6 %) was significantly higher compared with the NDKD+DM (27.9 %) and NS-DM (27.0 %) groups.
• The prevalence of rapid decliners in different urine total protein to creatinine ratio (UPCR) categories (<0.5, 0.5 to < 1.0, 1.0 to < 3.5, and ≥ 3.5 g/g) were equivalent between the DKD and NS-DM groups.
• The prevalence of a UPCR < 1.0 g/g in rapid decliners of the NS-DM group was more than double that in those of the DKD and NDKD+DM groups.

The findings showed that although NS-DM has a better kidney prognosis owing to its low proteinuria level, the kidney prognosis in NS-DM patients with a proteinuria level (0.5–1.0 g/g) may be worse than assumed.

"We propose a new concept that the effect (and weighting) of proteinuria on rapid kidney function decline may be different and greater in NS-DM patients with low proteinuria (0.5–1.0 g/g) levels compared with DKD or NDKD+DM patients with the same proteinuria level," the researchers wrote.

They suggested that even a relatively low proteinuria level of up to 0.5 g/g should be given more aggressive treatment in patients with NS-DM because they are more likely to experience a rapid eGFR decline versus patients with DKD or NDKD+DM.

Reference:

Gohda, T., Murakoshi, M., Suzuki, Y., Kagimura, T., Wada, T., & Narita, I. (2024). Effect of proteinuria on the rapid kidney function decline in chronic kidney disease depends on the underlying disease: A post hoc analysis of the BRIGHTEN study. Diabetes Research and Clinical Practice, 212, 111682. https://doi.org/10.1016/j.diabres.2024.111682