Osteoporosis

Updated 13 March 2015

How HIV treatment affects your bones

Many HIV positive patients are on Highly Active Antiretroviral Treatment (HAART), but the medications used in South Africa could be affecting your bones and even speed up the progression of osteoporosis.

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In South Africa approximately 5,51 million people are HIV positive, of which nearly 40% are currently receiving Highly Active Antiretroviral Treatment (HAART).

Since the introduction of HAART, the landscape of HIV in South Africa has changed considerably, as the drugs (colloquially referred to as  “miracle drugs”) have brought about a profound improvement in the quality of life and and increased life expectancy in HIV positive patients.

However, as with all medicines, HAART does have side effects and should be investigated and attended to in all people taking them. 

The side effects of HAART are usually very mild with a slight upset tummy, occasional nausea and vomiting or a rash being the most commonly reported negative effects.

Some side effects may only present after a period of time. A common side effect of HAART, lipodystrophy, where losing or gaining of body fat over a period of time can cause significant disfiguring and even stigmatisation, is not immediately apparent .

Some effects are not even noticed by the patient, as is the case with lipid abnormalities and metabolic bone disease (MBD) which is now a well-recognised and studied side effect of HAART.

What is metabolic bone disease?

MBD refers to spectrum of bone disorders caused by abnormalities in the metabolism of calcium, phosphorus, magnesium and vitamin D which is important in healthy bone development and maintenance.

Most well known are osteopenia and osteoporosis

Osteopenia describes the “thinning” of bone that is not yet as severe as is in the case of osteoporosis where the bone density deteriorates enough to change the micro-architecture of bone and subsequently makes the patient very prone to fractures.

The measurement of bone mineral density (BMD) is an accurate indication of the development and progression of bone conditions like osteoporosis.

Read: Common fracture sites for osteoporosis

HAART increases the development of MBD

Research show an increase in the development of metabolic bone disorders with the use of HAART. A meta-analysis done by researchers at Johns Hopkins University (USA)  showed very interesting numbers:

67% of a group of 884 HIV positive patients from various studies, had reduced BMD, with 15% having established osteoporosis.

Compared with the HIV negative control group, HIV positive patients had a:

- 6.4 fold increase in odds of having a reduced BMD
- 3.7-fold  increase in odds of osteoporosis. 

The analysis showed a two times greater occurrence of MBD in patients receiving HAART. 

Read: Risk factors for developing osteoporosis

The exact causes are unclear

The exact causes of these phenomena are not yet clear. Some research, although still highly controversial, suggest increased bone resorption. Others believe that the HIV virus has a direct effect on the activity of osteoclasts (cells found in bone responsible for the breakdown of old bone).  

A study published in the HIV/Aids Journal in 2010 states that a 2% to 6% decrease in BMD is expected over the course of two years once HAART is initiated. The study concluded that a complex interaction between the HIV infection itself, traditional osteoporosis risk factors and HAART-related factors.  

Several emerging studies showed a significant increase in fracture rates in HIV positive patients with some studies suggesting an increase of 30% to 70% in risk.

Read: Over 2.7 million South Africans on antiretrovirals

South Africa's treatment affects BMD

South Africa currently uses a fixed dose regimen of drugs consisting of Tenofovir, Emtricitabine and Efavirenz as first line treatment for newly diagnosed HIV positive patients.

A number of studies conducted on the use of Tenofovir showed the drug may cause a temporarily accelerated decrease in BMD in patients using the drug. This is most likely caused by phosphate wasting and an increase in bone turnover. Most studies suggest the decrease in BMD tend to stabilise over a period of time.

A decrease in vitamin D blood levels are seen in patients taking Efavirenz. Vitamin D is important in the absorption of calcium and phosphorous which is vital for healthy bone formation.

Few studies are available on the effects of  Emtricitabine and the development of MBD.

Interestingly, studies show that a decrease in BMD is noted across the board regardless of the initial choice of ART's.

Read: Stick to your ARV treatment plan

HAART benefits outweigh risks

The introduction of HAART changed the management of HIV globally. The most obvious question is whether the risk of MBD is of such a nature that HAART should be stopped.

The significant enhancement of quality of life for patients on HAART seem to outweigh the benefits of not taking the medication.

Although MBD may have detrimental effects on the life of a patient suffering, for example, a fracture, the overall effect HAART has on patient well being should not be ignored. 

Screening for possible MBD in HIV positive patients is important. Detailed history, physical examination and appropriate special investigations are integral in early detection and effective management of these disorders. Researchers recommend a Bone Density Scan for all HIV positive post-menopausal women and men aged 50 and over. Such investigations in younger patients are probably not indicated as the risk of fractures secondary to MBD are fairly low. Patient who have a history of fragility fractures should be investigated regardless of age.

Keeping bones healthy

Adequate nutrition is vital in maintaining healthy bones. Research suggest that HIV positive people should supplement their diets with additional calcium and vitamin D. 

Regular exercise will strengthen muscles to prevent falls and subsequent fractures. Weight-bearing exercises in post-menopausal women are especially indicated.

Co-morbid conditions must be managed effectively with specific treatment, i.e. if a patient suffers from hypothyroidism, it should also be attended to.

Cessation of smoking, moderate alcohol intake should be pursued.

Read more: 

Why vitamin D is good for you

Calcium cuts stress fracture risk

Do diet and lifestyle have an impact on osteoporosis?

Image: Pills from Shutterstock

Dr. Owen J. Wiese is Health24's resident doctor. After graduating from Stellenbosch University with additional qualifications in biochemistry and physiology he developed a keen interest in providing medical information through the media.

 

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Healthy Bones

Tereza is the CEO of the National Osteoporosis Foundation and worked as a Nursing Sister in the field of Osteoporosis for 18 years prior to her appointment with the Foundation. She used to be the Educational Officer for the Foundation and co-wrote the patient brochure on Osteoporosis. Read more

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