Kidney Biopsy-Proven Diabetic and Non-Diabetic Kidney Diseases and Outcomes in Patients With Type 2 Diabetes Receiving Dialysis: The REIN Registry

Rationale & Objective

Chronic kidney disease (CKD) in patients with diabetes does not always equate to diabetic kidney disease (DKD). This study aims to delineate and compare the clinical characteristics, survival rates, and access to kidney transplantation among patients with type 2 diabetes commencing dialysis, who were classified by kidney biopsy as having either DKD or non-diabetic kidney disease (non-DKD).

Study Design

We used the comprehensive French Renal Epidemiology and Information Network registry to analyze baseline clinical characteristics at dialysis inception and outcomes defined as death and access to kidney transplantation.

Outcomes & Analytical Approach

We employed a multivariate Cox proportional hazards model and the Fine-Gray competing risk model to assess the probabilities of mortality and transplantation.

Settings & Participants

Adults in the Renal Epidemiology and Information Network registry in France with a diagnosis of type 2 diabetes who initiated kidney replacement therapy from January 2009 to December 2015 and had a previous native kidney biopsy.

Results

We analyzed data from 2,869 patients with diabetes, 45% of whom had a biopsy-confirmed diagnosis of DKD. Among these patients, half presented additional histopathological findings indicative of nephroangiosclerosis and focal segmental glomerulosclerosis. The clinical profiles of patients with DKD and non-DKD were largely comparable. There were no significant differences in dialysis survival rates or kidney transplantation access between the groups, even after adjusting for confounding variables and considering competing risks. At the 6-year mark, the mortality rate was 60.3% (95% CI: 55.5-64.5) for the DKD group and 60.3% (95% CI: 55.9-64.3) for the non-DKD group. Multivariable Cox analysis revealed no significant difference in mortality risk between the DKD and non-DKD groups.

Limitations

The study limitations include potential residual confounders, lack of predialysis data, kidney biopsies possibly outdated, nonrandom biopsy indications, and survival bias because of analysis at dialysis inception.

Conclusions

In patients with diabetes initiating dialysis, clinical characteristics and outcomes following dialysis initiation were similar in biopsy-proven DKD versus non-DKD. Our results suggest that the diabetic milieu has a more significant impact on outcomes in patients with diabetes treated with dialysis than the underlying pathological kidney diagnosis.

Plain Language Summary

This study explored whether chronic kidney diseases in patients with diabetes are always caused by diabetes or if other conditions might be responsible. By examining medical records from the nationwide French registry, researchers compared patients with diabetic kidney disease to those with other kidney diseases (non-diabetic kidney disease). They found that clinical characteristics and survival rates were similar between both groups, and access to kidney transplantation was unaffected by the specific type of kidney disease. This suggests that, for patients with diabetes treated with dialysis, the overall impact of diabetes on health outcomes is more crucial than the exact kidney disease. Understanding this could help improve treatment strategies for patients with diabetes undergoing dialysis.