1. Overview & Rationale
Diabetes is a bidirectional issue in transplantation: it is the leading cause of kidney failure requiring transplant, and transplantation (and its associated medications) can cause new-onset diabetes.
- Kidney Transplant: For people with diabetes and End Stage Renal Disease (ESRD), kidney transplantation provides better long-term outcomes than dialysis.
- Beta-Cell Replacement: Whole pancreas or islet transplantation can restore endogenous insulin, stabilizing glucose and preventing severe hypoglycemia in Type 1 Diabetes.
- Post-Transplant Diabetes Mellitus (PTDM): A common complication after solid organ transplant, associated with reduced graft survival and increased mortality.
2. Transplantation Options for Type 1 Diabetes
A. Pancreas Transplantation
This involves major abdominal surgery but offers the highest chance of long-term insulin independence.
- Simultaneous Pancreas-Kidney (SPK):
- Indication: Type 1 Diabetes + ESRD.
- Benefit: Improves kidney graft survival compared to kidney transplant alone. It prolongs insulin independence and patient survival.
- Success: Median graft survival is ~9 years.
- Pancreas After Kidney (PAK): For those who already have a functioning kidney transplant.
- Pancreas Transplant Alone (PTA): Rare; for those with severe metabolic complications but preserved kidney function.
B. Islet Transplantation
A minimally invasive procedure where islets are infused into the liver via the portal vein.
- Islet Allotransplantation (Donor Islets):
- Goal: Primarily to prevent severe hypoglycemia and restore hypoglycemia awareness, even if total insulin independence isn’t achieved.
- Outcome: 5-year insulin independence rates have improved to ~60%.
- Islet Autotransplantation (Self Islets):
- Indication: People undergoing total/partial pancreatectomy for benign disease (e.g., chronic pancreatitis).
- Benefit: Prevents surgical diabetes; does not require immunosuppression because the cells are the patient’s own.
3. Comparison: Islet vs. Pancreas Transplant (Table 2)
This comparison is high-yield for the exam.
| Feature | Islet Transplant | Pancreas Transplant |
| Invasiveness | Minimally invasive (infusion) | Major abdominal surgery |
| Insulin Independence | Variable; may require multiple infusions | High rate; more durable |
| Primary Goal | Eliminate severe hypoglycemia | Insulin independence & Renal protection (SPK) |
| Immunosuppression | Required (Life-long) | Required (Life-long) |
| Steroids | Generally Avoided | May be used |
4. Post-Transplant Diabetes Mellitus (PTDM)
Formerly known as “New Onset Diabetes After Transplantation” (NODAT).
Risk Factors:
- General: Age, obesity, family history, metabolic syndrome.
- Transplant-Specific: Hepatitis C, Cytomegalovirus (CMV), Corticosteroids, Calcineurin inhibitors (immunosuppressants).
Screening & Diagnosis:
- Early Period (0–3 months):
- Hyperglycemia is common due to high-dose steroids and stress.
- Screening: Monitor post-lunch (4 pm) capillary blood glucose.
- A1C: NOT reliable in the first 3 months due to surgical blood loss/transfusions/turnover.
- Stable Period (>3 months):
- A1C 6.5% can be used for diagnosis once the patient is stable.
- OGTT: The standard 2-hour Oral Glucose Tolerance Test is the most sensitive but often impractical. Fasting Plasma Glucose (FPG) is the least sensitive.
Management of PTDM:
- Insulin: Preferred agent in the acute hospital setting or during high-dose steroid therapy.
- Metformin: First-line oral agent if renal function is stable.
- Secretagogues (Sulfonylureas/Meglitinides): AVOID in patients with renal impairment or pancreas transplant dysfunction to preserve beta-cell mass and avoid hypoglycemia.
- SGLT2 Inhibitors: Use with caution due to infection risk in immunosuppressed patients.
Diabetes CanadaClinical Practice Guidelines Recommendations
Key takeaways from the “Recommendations” section (Page 5147).
- SPK Selection: Individuals with Type 1 diabetes and ESRD should be considered for Simultaneous Pancreas-Kidney (SPK) transplantation [Grade C, Level 3].
- Islet Consideration: Islet allotransplantation may be considered for T1D with marked glycemic lability or severe hypoglycemia despite optimal care [Grade C, Level 3].
- PTDM Screening:
- Screen for PTDM with A1C at 3 months, 12 months, and annually [Grade C, Level 3].
- Use OGTT or post-lunch monitoring in the first 3 months (when A1C is unreliable) [Grade C, Level 3].
- PTDM Management:
- Treat to individualized targets.
- Avoid insulin secretagogues if renal impairment is present [Grade D, Consensus].
- Use insulin for metabolic decompensation [Grade D, Consensus].
Reference:
Senior PA, AlMehthel M, Miller A, Paty BW. Diabetes and Transplantation. Canadian Journal of Diabetes. 2018;42:S145-S149. doi:10.1016/j.jcjd.2017.10.017