What Causes Post-Transplant (New-Onset) Diabetes?

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Post-transplant diabetes (also known as new-onset diabetes) occurs when a person develops diabetes after they receive an organ transplant. The condition affects about 10% to 40% of people who undergo an organ transplant.

Post-transplant diabetes is usually caused by medications that keep the body from rejecting the new organ. These medications suppress the immune system, which is the body's defense against foreign invaders like bacteria or viruses. Other possible causes of new-onset diabetes include a family history of diabetes, high cholesterol and/or high blood pressure, and having been diagnosed with hepatitis C.

This article covers the causes and risk factors of new-onset diabetes, how to manage the condition, and how to work with your care team.

An older patient having their blood sugar checked with a finger prick glucometer by a masked healthcare worker.

Phynart Studio / Getty Images

Why Does Post-Transplant Diabetes Happen?

Post-transplant diabetes usually occurs because of medications that suppress the immune system. These types of medications are used to prevent the immune system from rejecting the new organ after a transplant.

Medications that can increase the chance of post-transplant diabetes include:

  • Post-transplant medications: These medications affect cells in the pancreas, a gland that produces chemicals to digest food. These chemicals include insulin, the hormone responsible for taking sugar from the blood and into the body's tissues for use.
  • Steroids: These medications are human-made versions of hormones that lower inflammation, which is the body's response to invaders (such as when an injury swells while it heals). Organ recipients can be prescribed glucocorticoids, which can make the body resist insulin.

Risk Factors

There are risk factors that can increase the likelihood of post-transplant diabetes. Some of them are preventable while others are not.

These risk factors might be preventable for some people:

  • Obesity or being overweight: Excess weight can affect cells in the pancreas, where insulin is produced.
  • High cholesterol or high triglycerides: Having excess cholesterol or fat in the blood affects how cells in the pancreas make insulin.
  • High blood pressure: High blood pressure can affect how blood vessels and cells react to insulin.
  • Hepatitis C: The hepatitis C virus can damage cells in the pancreas (where insulin is made) as well as cause insulin resistance.

Risk factors for post-transplant diabetes that you cannot change include:

  • A family history of diabetes or new-onset diabetes
  • Being older than age 40
  • Race/ethnicity (Black and Hispanic patients are more likely to get new-onset diabetes after an organ transplant)
  • Pregnancy

Management and Lifestyle Tips

Lifestyle adjustments can help manage or even prevent new-onset diabetes. When creating a post-transplant management plan with your healthcare provider, you might consider making the following changes.

Learn How to Check Blood Sugar

Monitoring blood sugar with at-home tests and getting tested for diabetes regularly can help you get ahead of new-onset diabetes.

At-home blood sugar tests usually involve pricking your finger and reading results in a continuous glucose monitor (CGM). Blood sugar standards depend on a person's age, the time of day they are self-testing (such as before or after a meal), and their other health conditions.

Diabetes tests done by a healthcare professional can include:

  • A1C test: Average blood sugar over two or three months
  • Fasting blood sugar: Blood sugar after waking and before having anything to eat or drink
  • Glucose tolerance: Blood sugar before and after drinking a sugary beverage
  • Random: Blood sugar levels at the time when the test is taken

Understand Food Nutrition Labels

Eating non-starchy vegetables, whole grains, and lean protein while avoiding sugary drinks, processed food, and trans fats can help with diabetes prevention and management after a transplant.

When you're reading food labels to manage your diabetes risk, here are a few key points to keep in mind:

  • Monitoring serving size: Eating larger meals can raise your blood sugar for a longer time.
  • Tracking total carbohydrates, fiber, and sugar: You can subtract the amount of fiber from the total carbohydrates because fiber does not increase blood sugar. Sugar alcohols are considered carbohydrates, though they might be counted as half the amount. Ask your provider or nutritionist how many carbohydrates you can have daily.
  • Limiting saturated fats, trans fats, and cholesterol: Limiting trans fats and cholesterol can lower your risk for heart disease.
  • Eating lean protein: Protein takes longer to convert to sugar (glucose) in the body, which can help with snacking. With larger meals, there is some risk of elevated glucose for an extended time. People with kidney conditions might need to monitor their protein intake. Ask your provider or nutritionist about the right amount of protein for your diet.

Maintaining a Healthy Weight

Excess weight can create insulin resistance. Talk with your healthcare provider about the weight you should set as a goal for your health, and how you can work toward reaching and maintaining it.

Treating and Preventing Metabolic Syndrome

Metabolic syndrome is a term that refers to several conditions that raise the risk of diabetes and heart disease. Treating and managing these conditions with changes to your diet and lifestyle and sometimes medication can help prevent diabetes.

Metabolic syndrome includes:

  • High blood pressure
  • High triglycerides
  • High LDL ("bad") cholesterol and low HDL ("good") cholesterol
  • Obesity

Exercise

Studies show that exercising for 30 minutes (like walking at a moderate pace) can help reduce insulin resistance and lower blood sugar.

Diabetes Care Team After an Organ Transplant

Post-transplant care can include monitoring medication reactions, side effects like nausea, surgery complications, possible infections, kidney function, and diabetes risk. A diabetes care team that works together can be crucial for meeting a transplant patient's needs. This team can include healthcare professionals like:

  • Nutritionists
  • Diabetes educators
  • Nurses
  • Transplant surgeons
  • Kidney specialists (nephrologists)
  • Endocrinologists (providers who specialize in hormones)
  • Infectious disease specialists

Summary

Post-transplant diabetes is usually caused by medications that suppress the immune system, which normally fights against foreign invaders in the body. Immunosuppressant medication can interfere with cells in the pancreas, an organ near the stomach that produces insulin. Insulin is the hormone that takes sugar from the blood so the body can use it. When the body does not make or respond to insulin, diabetes can develop.

Some risk factors for post-transplant diabetes might be things you can work on changing, like high blood pressure, cholesterol, and triglyceride levels (metabolic syndrome); obesity, and hepatitis C. Some risk factors that are not things you can change include a family history of diabetes, age, and ethnicity.

You can support your cardiovascular health with a nutritious diet, regular exercise, and medication if needed. It's also key to monitor your blood sugar levels with self-testing and diabetes testing, as well as working with a diabetes care team. These steps may help prevent post-transplant diabetes but can also help you manage new-onset diabetes.

A Word From Verywell

While post-transplant care can seem complicated, preventing or managing post-transplant diabetes is something many patients can feel empowered about. With a lifestyle that includes some moderate exercise, nutritious food, at-home blood sugar monitoring, and working with a care team, it can be possible to take one part of your post-transplant care into your own hands.

Frequently Asked Questions

  • Can you reverse new-onset diabetes?

    A 2020 study where human cells were put in mice showed that it might be possible to reverse new-onset diabetes caused by immunosuppressant drugs by administering drugs used to treat type 2 diabetes. The study authors suggested their findings could mean the diabetes risk of post-transplant drugs could be minimized, but more research is needed.

  • Why do post-kidney transplant medications cause diabetes?

    Post-kidney transplant medications suppress the immune system and minimize inflammation. These immunosuppressant drugs also affect cells in the pancreas that make insulin, the hormone in charge of taking sugar from the blood and getting it into the organs for use.

  • Can you take Metformin if you’ve had an organ transplant?

    A 2018 study found that kidney transplant patients on Metformin had a 59% higher chance of survival. Heart transplant patients on Metformin could increase their chance of survival by almost 70%. Liver transplant patients could also increase survival odds with Metformin.

    However, healthcare providers may consider Metformin dangerous for kidney transplant patients who receive insulin before surgery, while others might prefer to wait until kidney function improves before prescribing the drugs.

24 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Neha Kashyap
Neha is a New York-based health journalist who has written for WebMD, ADDitude, HuffPost Life, and dailyRx News. Neha enjoys writing about mental health, elder care, innovative health care technologies, paying for health care, and simple measures that we all can take to work toward better health.