Living kidney donation addresses the critical shortage of organs for patients with end-stage renal disease. When individuals with chronic conditions like diabetes consider donation, a complex medical evaluation is required. Diabetes is the leading cause of kidney failure globally, making the assessment of a diabetic donor focus entirely on minimizing risk to the individual’s future health. Transplant centers must ensure the long-term safety of the donor, leading to a highly individualized and rigorous screening process.
Eligibility Criteria for Diabetic Donors
Eligibility for donation hinges on the type and control of diabetes, with a distinction drawn between the two major forms. Individuals with Type 1 diabetes, which requires insulin for survival, are almost universally excluded from living kidney donation. This is due to the underlying autoimmune destruction of insulin-producing cells and the associated high, long-term risk of kidney damage. Type 1 diabetes presents an unacceptable lifetime risk of developing end-stage renal disease (ESRD) with only one remaining kidney.
The criteria have recently shifted for people with Type 2 diabetes, who may now be conditionally eligible following a 2022 policy update by the Organ Procurement and Transplantation Network (OPTN). Eligibility is not guaranteed but is considered on a case-by-case basis. Candidates must show no evidence of existing organ damage and present an acceptable lifetime risk of complications. This assessment focuses on strict metrics that demonstrate long-term, excellent disease control.
The Hemoglobin A1C test is a primary screening tool, measuring average blood sugar control over the previous two to three months. Centers often require a consistently low A1C level, sometimes \(\le\)7%, demonstrated over multiple tests to verify sustained adherence and control. Furthermore, a candidate must have a measured Glomerular Filtration Rate (GFR) greater than \(80-85 \text{ mL/min}\), confirming robust baseline kidney function.
The mandatory absence of microalbuminuria or proteinuria is the most non-negotiable requirement, as these are early markers of kidney damage. These tests check for small amounts of protein leaking into the urine, indicating that the kidney’s filtering units are compromised. Candidates must have a urine albumin-creatinine ratio less than \(30 \text{ mg/g}\) to proceed. Other factors considered include being older (often \(\ge\)55 or \(\ge\)60) and having a short duration of diabetes, which limits exposure to high blood sugar.
Diabetes and Kidney Function
The rigorous screening criteria exist because of how high blood sugar affects the body’s filtration system. Sustained hyperglycemia physically damages the delicate microvasculature throughout the body, a process termed diabetic microangiopathy. This damage is particularly pronounced in the kidneys, leading to diabetic nephropathy.
The kidneys contain millions of tiny filtering units called glomeruli, which act as sieves, allowing waste and excess water to pass into the urine while retaining useful proteins and blood cells. Elevated glucose levels cause the blood vessels in these glomeruli to thicken and scar over time. This scarring reduces the glomerulus’s filtering efficiency and increases its permeability, causing proteins like albumin to leak into the urine.
Initially, the remaining, undamaged nephrons may work harder to compensate, a state called hyperfiltration, which can mask underlying injury. Over many years, the progressive damage compromises the overall filtration ability of the organ. The removal of one kidney forces the remaining, potentially susceptible organ to manage the entire filtration load while still being exposed to the ongoing effects of diabetes.
Long-Term Health Considerations Post-Donation
For a diabetic individual who successfully donates a kidney, the long-term health outlook requires continuous, proactive management. After donation, the remaining kidney naturally increases its workload to maintain filtration needs, a process called compensatory hyperfiltration. While the remaining kidney can function adequately, the diabetic donor carries a unique, heightened risk compared to a non-diabetic donor.
The major concern is the accelerated risk of developing End-Stage Renal Disease (ESRD) later in life. Although precise, long-term comparative data for diabetic donors is limited, the known progression of Type 2 diabetes means the single remaining kidney is at a higher risk of succumbing to diabetic nephropathy. The remaining kidney must manage the full burden of filtration while facing the same underlying disease process.
Lifetime monitoring is mandatory for the ongoing safety of the donor. This monitoring includes regular checks of kidney function, specifically the Glomerular Filtration Rate (GFR), to detect any decline early. Rigorous control of blood pressure and blood sugar is imperative, as hypertension and hyperglycemia accelerate kidney damage. A diabetic donor must commit to lifelong adherence to medical advice, diet, and lifestyle changes to preserve the function of their remaining kidney.