Friday, September 24
11:03 AM

Osteoporosis: Making no bones

5 May 2021

Osteoporosis is a disease that weakens bones to the point where they break easily, more often, bones in the hip, spine and wrist. Osteoporosis is called a ‘silent disease’ because you may not notice any changes until a bone breaks. “An early assessment of an individual’s risk of developing osteoporosis is important to prevent the first fracture from happening,” says Dr Biswajit Dutta Baruah, consultant orthopaedic surgeon, KIMS Oman hospital.

 

Osteoporosis is a medical condition affecting all the bones in the body. It is characterised by loss of bone mineral, weakening of the bone and change in the micro-structure of bone. This makes the bone susceptible to fractures with minor injury or fall (low energy), resulting in what doctors refer to as fragility fractures. 

As the change in the bone structure is gradual and does not result in any symptoms, the development of osteoporosis goes unnoticed for a long time. It is diagnosed after the first fracture has occurred making a visit to the doctor imperative.

An early assessment of an individual’s risk of developing osteoporosis is important to prevent the first fracture from happening. One group that is particularly vulnerable comprises women who have achieved menopause. Then, there are elderly men who have been home bound, usually in their 70s or 80s.

Elderly patients often suffer from other conditions like blood pressure, diabetes, bronchitis, stroke or cancer that can take up all their time in the hospital. Sadly, this results in both doctor and patient ignoring the development of osteoporosis. High suspicion on behalf of the doctor and an educated patient can help uncover and mitigate the impending risk of this condition.

 

Loss of mobility

About 40% of women in the post menopausal phase have osteoporosis. This number is steadily rising. In such women, the lifetime risk of developing a fracture is as high as 40%. Most commonly these fractures affect the hip, spine and the wrist. Other bones like the trochanter (top portion of the thigh bone), humerus (arm bone) and the ribs may be affected as well.

A fracture often leads to loss of mobility and a subsequent drop in their ability to perform activities independently. This severely impacts their quality of life. In addition to this, in case of osteoporotic fractures involving the hip and spine, there is an increased risk of death (unto 20%) in the first 12 months (high mortality risk). This is due to the fact that they need hospitalisation, and are prone to developing complications like pneumonia or blood clots due to their immobile status.

Other risk factors that enhance the risk of osteoporosis are low body-mass index (BMI), previous fragility fractures, history of such fractures in the family, use of steroids (like cortisone) and active smoking.

 

Assessing bone density

The number one tool to assess the mineral-density of bone (BMD) is dual x-ray absorptiometry (DXA or DEXA scan for short). A T-score value of minus 2.5 SD indicates osteoporosis. Fracture-risk assessment tool (FRAX) is available that integrate the BMD assessment along with other clinical risk factors to give an individual’s risk of developing a fragility fracture in the next ten years. You will need the help of your doctor to make use of this tool.

High risk will mean aggressive treatment to counter or reverse the effects of osteoporosis. Biochemical markers of bone resorption like measuring the levels of NTX in urine or CTX, PINP & BSAP in blood serum are available but not routinely employed as DEXA scan is considered sufficient to make a diagnosis of osteoporosis.

The biochemical markers are employed to follow up patients or used by clinical researchers to assess the efficacy of drugs used to treat osteoporosis.

 

Lifestyle changes

Appropriate lifestyle choices like complete cessation of smoking, reduction in alcohol consumption and increased physical activity are important in treating osteoporosis.

Making sure that the home environment does not contribute to the risk of falls is critical for elderly patients. Making sure that washrooms have non-slippery surfaces and are dry, floor mats have rubber bottoms, beds are close to washrooms, light switches are at reach if they want to make a trip to the washroom, floors are not littered with toys and that the room has minimum furniture can make a world of difference in preventing falls at home.

As baseline treatment, almost all of them will need to be supplemented with Vitamin D and calcium.  All osteoporotic drugs are effective only when these are provided at the same time. It goes without saying that increased dietary intake of calcium via natural food is preferable over calcium supplements.

 

Process of bone making 

Though bones are of the same size and shape in adulthood, they are metabolically active and undergo active remodelling all the time. Bone is being removed (resorptive process) and formed (anabolic process) at the same time. A balance between these two processes maintains the density of bone. In post-menopausal women, elderly men or in those who are bed bound, the rate at which bone is formed is not able to keep up with the rate at which bone is being removed resulting in weak bones or osteoporosis.

Medicines that are used to treat osteoporosis are largely of two types, ones that counter the resorptive process (antiresorptive drugs) and those that stimulate more bone formation (anabolic drugs). Among the antiresorptive drugs, bisphosphonates are used the most often as they are inexpensive. They are available as oral tablets (eg: Fosamax) or can be administered intravenously (IV medication eg: Aclasta). They bind to bone well and have a long safety record.

 

Oral medications

Oral medications are prescribed usually on a once a week basis. When orally ingested they can cause severe heartburn, and patients are advised to remain upright for an hour following ingestion of the medicine. Long term administration makes adherence to the treatment an issue of concern.

IV preparations are usually given on a yearly basis and have much better adherence as a result but are expensive. Newer drugs like Denosumab (eg: Prolia) target the bone resorptive cells (osteoclasts) and have been found to be effective in treating osteoporosis. They are usually given on a half-yearly basis.

With antiresorptive therapies, necrosis of the jaw bone or pathological fractures of the thigh bone (femur) have been reported. So, a yearly review with your treating doctor is necessary. To mitigate this risk, bisphosphonates are usually discontinued after 3-5 years of therapy. If the risk of osteoporosis persists, the doctor may resort to other available therapies.

Other oral preparations like raloxifene have gone out of practice due to high risk of developing blood clots. Among the anabolic drugs, full-length parathormone (PTH 1-84) and a fragment of the parathormone (PTH 1-34 available as teriparatide) are given as subcutaneous injections. They are prescribed as daily doses and are available in pen injection format similar to insulin pens. 

In summary osteoporosis is an insidious condition that can affect post-menopausal women and the elderly. It calls for early detection in order to prevent fractures from happening. DEXA scan is useful in diagnosing the condition. Several drugs are available for treatment and a discussion with your treating doctor will help identify the appropriate drug. Vitamin D and calcium supplements are necessary, as well. 

 

 

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