What is Transplantation Osteoporosis?

Organ transplantation, where a healthy organ is transferred from one person to another, has become a recognized treatment for various severe diseases. These include diseases where critical organs like the kidneys, liver, heart, and lungs, pancreas, intestines, or blood-forming (hematological) conditions reach a stage where they can no longer function properly. In the last thirty years, the number of organ transplants done globally has grown steadily.

This rise in successful transplants is largely due to newer medicine (immunosuppressive regimens) that prevent the body from rejecting the new organ, and improvements in nutrition. This has greatly improved the survival rates of those who have undergone transplants. However, as the number of transplant procedures increases, so does our awareness of the potential short and long-term complications.

A complication that has been identified is the development of osteoporosis (where bones become weak and brittle) and fractures after transplantation. These issues are linked with increased illness and death rates and have been shown to decrease the quality of life in those who have received transplants.

What Causes Transplantation Osteoporosis?

There are two main reasons why people who have undergone a transplant often face a higher risk of bone loss and fractures. The first is a pre-existing bone condition before the transplant, and the second is exposure to high doses of certain medications – glucocorticoids and calcineurin inhibitors – after the transplant.

There are also several factors that can’t be changed, but are linked to a higher risk of developing osteoporosis after a transplant. These include being older, being white, being female, and especially being in the period after menopause.

Risk Factors and Frequency for Transplantation Osteoporosis

Some recent studies indicate lower rates of osteoporosis and fractures in transplant recipients compared to the general population. However, even these lower rates are still much higher than those seen in people of the same age and gender who haven’t undergone a transplant. This improvement in rates is likely due to better awareness, early diagnosis, and treatment of osteoporosis and improved procedures around transplants.

In a large study in 2014, it was found that the risk of osteoporosis was over five times higher after solid organ transplantations such as heart, lung, liver, and bone marrow procedures. Male patients and those under 50 had the highest risk. The most significant bone loss occurs in the first few months after a transplant, and the loss ranges from 2% to 12% in the first year.

11-57% of transplant recipients developed osteoporosis within the first year after the procedure.
14 -65% experienced fractures in the same time period.
The rates vary depending on the type of organ transplanted and how long the person has been monitored after the procedure.
Fractures were least common among kidney transplant recipients in the first year after transplantation.
The highest rates of osteoporosis and fractures were recorded in lung transplant recipients.
Despite some improvement over time, bone mineral density remains low for many years after kidney transplantation.

Signs and Symptoms of Transplantation Osteoporosis

People who’ve had an organ transplant may develop a condition called “transplantation osteoporosis”. This can cause symptoms such as bone pain, fractures from minor falls or injuries, or changes in bone shape. However, doctors don’t always look for this condition in people who’ve received transplants. So, if someone’s had a transplant, it’s important to consider the possibility that they might have osteoporosis and related problems. This can help to diagnose the condition quicker.

Testing for Transplantation Osteoporosis

People who are in line for organ transplants tend to have a higher risk of bone disease compared to the general population. So, it’s important that these people are checked for any bone problems and treated appropriately before they get their transplant.

But how exactly bone problems are checked and managed varies, depending on the organ that needs to be transplanted and the specific disease the patient has. For instance, the American Association for the Study of Liver Diseases (AASLD) and the American Society of Transplantation (AST) have guidelines that recommend that all patients set to get a liver transplant should have a bone density scan (also called a DXA scan). If this scan shows that they have osteoporosis (a condition that weakens bones), they should be treated before the transplant. Similarly, there are guidelines from the Kidney Disease Improving Global Outcomes (KDIGO) that recommend monitoring the levels of calcium, phosphorus, vitamin D, and PTH (a hormone that controls calcium levels in the blood) in patients after they’ve had a kidney transplant, until these levels become steady.

Most experts also advise that all transplant candidates, no matter what organ they’ll be getting, should have several tests to check for bone problems:

– A DXA scan to check for osteoporosis or osteopenia (a mild thinning of the bone mass).
– X-rays of the middle and lower part of the spine, or a test called vertebral fracture assessment (VFA) to look for any fractures in the spine.
– Tests to look for vitamin D deficiency and other causes of osteoporosis. These include overactive parathyroid glands, alcohol abuse, chronic smoking, lower than normal levels of sex hormones, and the use of certain medications, like heparin (a blood thinner) and loop diuretics (which help get rid of excess fluid in the body).

The time spent waiting for a transplant could be used to identify any potential causes of osteoporosis and treat them before the transplant. If osteoporosis or related fractures are found before a transplant, treatment should be started right away. For those who don’t have osteoporosis or fractures before their transplant, preventing these problems from developing after the transplant is the best approach.

Treatment Options for Transplantation Osteoporosis

Managing bone thinning after organ transplant, also known as transplantation osteoporosis, involves three main strategies:

1. Preventive medication
2. Treatment of established osteoporosis, and
3. Treatment of secondary causes of osteoporosis.

**Preventative Medication**

Major health organizations recommend preventive medication for all heart and liver transplant recipients throughout their first year after transplantation. This is especially important for patients with osteopenia, a condition where bone mineral density is lower than normal, who have other risk factors for fractures. This recommendation extends to patients undergoing heart, liver, lung, and bone marrow transplantations.

In kidney transplant recipients, there is not a clear agreement about preventive medicinal therapy. Instead, it’s usually recommended to evaluate these patients’ risk of fractures based on various factors including age, gender, body weight, and levels of certain substances in the body. Preventive therapy is then considered for patients who are identified as high-risk.

**Bisphosphonate Therapy**

Bisphosphonate therapy is usually the first choice for preventing transplantation osteoporosis as it counteracts the effects of corticosteroids, drugs that decrease your immune system’s response to prevent organ rejection after transplantation. These medications have shown success in reducing bone loss and lowering the number of fractures that occur within the first year after transplantation. However, it’s important to note that bisphosphonates aren’t recommended for patients with severe kidney disease or for women who may become pregnant, as their safety has not been thoroughly proven in these cases.

**Vitamin D Metabolites**

Medications derived from vitamin D, such as calcitriol, can be used to prevent osteoporosis when bisphosphonate therapy isn’t suitable. These medicines increase the absorption and reabsorption of calcium in your body, decreasing the amount of parathyroid hormone (PTH), which in high amounts can lead to bone disease. Still, all patients on this therapy must be checked regularly for too much calcium in the blood or urine.

**Hormone Replacement Therapy (HRT)**

HRT can slow down bone loss in transplant recipients with hypogonadism, a condition that results in low levels of sex hormones.

**Denosumab and Teriparatide**

Denosumab, an antibody medication that blocks a certain protein, can also be used in treating osteoporosis in kidney transplant recipients. However, discontinuing denosumab can lead to increased bone loss.

Teriparatide, a synthetic parathyroid hormone, has shown some promise in treating osteoporosis caused by steroids. However, its effectiveness as preventive therapy for transplantation osteoporosis requires further study.

**Calcitonin**

Calcitonin, a hormone that can inhibit bone loss, may also have a role in preventing and treating post-transplant osteoporosis, but more studies are needed to confirm this.

**Non-medicinal Measures**

To decrease the risk of osteoporosis and fractures after transplantation, patients are advised to stay active, improve nutrition, and avoid fall risks.

**Treatment of Transplantation Osteoporosis**

If a patient is already suffering from osteoporosis after a transplantation, the approach is to correct secondary causes and begin medicinal therapy, typically with bisphosphonates. Other drugs like denosumab and teriparatide can be used if bisphosphonates aren’t suitable or effective.

**Treatment of Secondary Causes of Osteoporosis**

Secondary causes of osteoporosis such as hyperparathyroidism (overactive parathyroid glands) and hypogonadism need to be identified and treated. Patients will also need to ensure they are getting enough calcium and vitamin D and generally make healthy lifestyle choices such as quitting smoking and reducing alcohol intake. It’s also important to minimize the level of immune-suppressing drugs used to avoid organ rejection.

Osteoporosis is usually detected through a specific type of scan called a DXA scan. However, this method can sometimes confuse osteoporosis with other conditions that result in low Bone Mineral Density (BMD). These conditions might include ‘osteomalacia’, a bone-weakening disorder that can happen in people with cystic fibrosis or liver failure, or ‘adynamic bone disease’, which can occur in people with End-Stage Renal Disease (ESRD).

Because accurate diagnosis is vital for determining the best treatment plan, doctors need to be careful when evaluating these scan results. If there’s any doubt, additional tests, such as a bone histomorphometry (a detailed analysis of bone structure), might be necessary for a more precise diagnosis.

What to expect with Transplantation Osteoporosis

Despite more understanding and awareness about osteoporosis (a disease that weakens bones making them more likely to break) as a possible complication after getting a transplant, it’s not common for doctors to evaluate and treat transplant candidates for this condition early on. When osteoporosis isn’t treated, it can increase the chances of fractures and the need for hospital stays. This can ultimately lead to more illness and a higher risk of death among people who’ve received transplants.

Possible Complications When Diagnosed with Transplantation Osteoporosis

The most severe problem after a bone transplant, known as post-transplantation osteoporosis, is experiencing bone fractures. The most common are vertebral compression fractures, but weaker fractures of the appendicular skeleton, or bones of the arms and legs, can also occur. These fractures can cause deformities in the bones which can limit movement and decrease a patient’s quality of life.

Common Side Effects:

Vertebral compression fractures
Low impact fractures of the appendicular skeleton
Bone deformities
Decreased mobility
Impaired quality of life

Preventing Transplantation Osteoporosis

Individuals who need a transplant should be informed in the early stages about the possibility of developing a condition known as osteoporosis after their transplant. Osteoporosis is a disease that weakens the bones, making them more likely to break. They may need specific treatments to manage this condition.

It’s also recommended for patients to change their lifestyle in certain ways. Quitting smoking, avoiding excessive drinking, and being more physically active can help lessen their risk of getting osteoporosis. Starting these habits early can also improve a patient’s health outcomes.

Early and effective advice can greatly help patients to follow medical advice and stick to their treatment plan in the future. This might not only prevent osteoporosis but also enhance the overall success of the transplant.