Recurrent Diabetic Nephropathy in Transplant Recipients

San Diego—There are few data on recurrent diabetic nephropathy in kidney transplant recipients. Aleksandra Kukla, MD, and colleagues at the Mayo Clinic in Rochester, Minnesota, conducted a study designed to identify the incidence, timing, and severity of recurrent diabetic nephropathy in transplant recipients with pretransplant type 1 and type 2 diabetes. Results of the study were reported during a poster session at Kidney Week 2018 in a poster titled High Incidence of Recurrent Diabetic Nephropathy in Kidney Transplant Alone (KTA) Recipients.

The study population (n=118) included diabetic transplant recipients with type 1 diabetes (simultaneous kidney/pancreas transplant [dual transplant]) and kidney transplant alone, and recipients with type 2 diabetes (kidney transplant alone). All patients underwent transplant between 2002 and 2009.

Recipients with simultaneous kidney/pancreas transplant had a functioning pancreas allograft at 5 years post-transplant. All recipients underwent surveillance protocol kidney biopsy at 4 months, 1 year, 2 years, and 5 years post-transplant. Recurrent diabetic nephropathy was diagnosed based on light microscopy according to Banff 2015 criteria (MM score) and/or as described by pathologist if the MM score was not assigned. Advanced recurrent diabetic nephropathy was diagnosed if MM score was >1. Patients with immune complex diseases were excluded.

Of the 118 study participants, 52 had type 1 diabetes (46% dual transplant and 54% kidney transplant alone) and 66 had type 2 diabetes (all kidney transplant alone). Compared with those in the type 2 group, those in the type 1 group were younger (47 years vs 62 years; P<.001). Body mass index (BMI) was similar between the two groups.

The earliest recurrent diabetic nephropathy was seen at 1 year post-transplant. At 5 years post-transplant, the incidence of recurrent diabetic nephropathy was 4.3% in the type 1 group with dual transplant, compared with 34% among patients with type 1 diabetes with kidney transplant alone and 46% among patients with type 2 diabetes with kidney transplant alone (P<.05). In those with recurrent diabetic nephropathy, BMI was higher regardless of diabetes type (34.5 vs 29.9; P<.05).

At 5 years, 13 recipients developed advanced recurrent diabetic nephropathy. Those that developed advanced disease were more likely to be in the type 2 group (74% vs 26% for type 2 and type 1, respectively; P<.05). Mean hemoglobin A1c in this group at 5 years was 8.12%. At 5 years, mean albuminuria was 52 mg. Seven (53%) recipients with advanced recurrent diabetic nephropathy did not have significant albuminuria at 5 years (≤30 mg/24 hours).

In conclusion, the researchers said, “Histologic changes of recurrent diabetic nephropathy can be seen as early as 1 year post kidney transplant and have high incidence at 5 years. High BMI is a risk factor. Pancreas transplantation is associated with histological protection. Advanced recurrent diabetic nephropathy is significantly more common in type 2 diabetes recipients and may be clinically silent. Future studies should focus on identifying risk factors for recurrent diabetic nephropathy, its impact on graft survival, and development of better noninvasive biomarkers of histologic injury.”

Source: Kukla A, Alvarez MCM, Bentall AJ, et al. High incidence of recurrent diabetic nephropathy in kidney transplant alone (KTA) recipients. Abstract of a poster presented at the American Society of Nephrology Kidney Week 2008, October 25, 2018, San Diego, California.