Risk of kidney failure in biopsy-verified kidney disease type in type 2 diabetes: A registry-based longitudinal...

The risk of kidney failure (KF) varies among people with diabetes and chronic kidney disease. We aimed to investigate whether the risk of progression to KF differs by biopsy-proven type of kidney disease in type 2 diabetes (T2D).

In this registry-based longitudinal cohort study, we identified all Danish adults with T2D who had a clinical kidney biopsy performed between 1994 and 2022. Using Poisson regression, we calculated the cumulative risk of KF with death as a competing risk.

We included 1203 individuals in the study, of which 1164 could be included in the final analysis: 483 had Diabetic Nephropathy (DN), 117 had mixed disease (coexistence of DN and non-DN (NDN)), and 564 had NDN. The risk of KF [95% CI] was 35% [29-42%] in DN, 18% [14-23%] in NDN and 33% [24-43%] in mixed disease after 3 years, and 47% [40-54%] in DN and 23% [18-29%] in NDN after 5 years. The 5xyear risk was not estimated for mixed disease due to the low number of cases. In DN, there was a significantly higher risk of KF from 3 to 5 years after the biopsy compared to NDN. In mixed disease, there was a significantly higher risk of KF compared to NDN after 3 years. There was no significant difference in the risk of KF between DN and mixed disease, however, the study may have been underpowered to detect a meaningful difference.

Biopsy-proven DN and mixed disease are associated with an increased risk of KF compared to NDN in T2D. The study underscores the severity of kidney disease in T2D when histopathological changes caused by diabetes are present.