Treatment of Osteoporosis
The aim of treatment is to prevent the development of osteoporosis and to prevent further bone loss in order to decrease the risk of osteoporotic fracture. Today there is a wide range of therapeutic options and several safe and effective pharmacological treatments that have been shown to act quickly (within one year) and to reduce the risk of fracture by up to 65% and nonvertebral fractures by up to 53%. It is important that the choice of treatment be tailored to a patient's specific medical needs and lifestyle.
Osteoporosis can be managed and treated by physicians from various areas of specialization; including general practitioners, endocrinologists, gynaecologists, rheumatologists, and orthopaedic surgeons. Osteoporosis patient and medical societies may be able to provide further information about physicians with special expertise in treating osteoporosis.
Types of therapy
There are different types of drugs used to treat osteoporosis: antiresorptive drugs, which slow the progressive thinning of bone, bone forming drugs which help to rebuild the skeleton, and drugs with a more complex mechanism of action. In addition to drug therapy, calcium and vitamin D supplements might also be prescribed to ensure adequate intake and to ensure maximum effectiveness of the drug therapy.
Bisphosphonates inhibit bone resorption. They are currently the first choice of treatment in a variety of bone metabolism disorders characterised by high bone resorption. They bring about an increase in bone mass and a decrease in fracture incidence in osteoporosis. There are different types of bisphosphonates which differ widely in their efficacy, side effects and possible routes of administration, thus offering a flexible range of therapeutic options.
Alendronate has been extensively studied for the treatment of osteoporosis under randomized controlled clinical trial conditions. Alendronate increases BMD at all skeletal sites and reduces the incidence of fracture by around 50% in both hip and spine. A newer bisphosphonate, risedronate, has also been shown to increase BMD in postmenopausal women, reduce the rate of vertebral and nonvertebral fractures and reduce the risk of hip fractures in elderly women with a low BMD. Alendronate and risedronate are given orally, daily or weekly. Oral ibandronate has also been shown to increase BMD and reduce the risk of vertebral fractures, and is given monthly. For ibandronate, effects on non-vertebral fractures have been derived from post-hoc analysis performed in high risk subjects. Zoledronate, given once a year as an intravenous infusion, is in the late clinical development stage.
Selective estrogen receptor modulators (SERMS) mimic estrogens in some tissues and anti-estrogens in others, and ideally provide the bone-retaining effects of estrogen without its unwanted side effects. Currently, the only marketed SERM is raloxifene. Raloxifene prevents bone loss and is indicated for the prevention and treatment of vertebral fractures in postmenopausal women. The incidence of new spinal fractures is reduced by 30-50% according to existence or not of vertebral fractures at baseline – so far, no significant reduction in non-vertebral fractures has been reported outside post-hoc analyses performed in high risk subjects. Raloxifene lowers serum cholesterol, does not induce endometrium bleeding or proliferation, and markedly decreases the incidence of breast cancer in osteoporotic women. Other SERMs, such as bazedoxifene and lasofoxifene, are in the late stages of clinical development.
Tibolone is a synthetic analog of the gonadal steroids with combined estrogenic, progestogenic and androgenic properties. Its effects on BMD are comparable to those of hormone replacement therapy. Its efficacy on fracture risk has not yet been assessed.
Intranasal or injectable calcitonin is an alternative to HRT or bisphosphonates. Salmon calcitonin nasal spray reduces the incidence of vertebral fractures by 25-35% at a daily dose of 200 IU. This is a smaller reduction than that achieved by bisphosphonates or raloxifene, but some patients may benefit from the analgesic effect intranasal calcitonin has on bone pain. Salmon calcitonin nasal spray is available in some countries for the treatment of patients with vertebral fractures.
Hormone Replacement Therapy (HRT)
As a result of new studies on large numbers of women, the role of HRT has recently been re-evaluated. Although HRT has been shown to have a beneficial effect on bone and is still an option for the treatment of menopausal symptoms, there are other more effective and non-hormonal therapies available for the treatment of osteoporosis.
Parathyroid Hormone (Teriparatide)
The bone-forming effects of parathyroid hormone (PTH) have been known to exist for more than 70 years. However, it is only during the last decade that data have emerged that provide consistent and encouraging results in animals and humans. A recent multinational study on postmenopausal women with prior vertebral fractures demonstrates that a synthetic fragment of PTH (teriparatide) is useful in the management of osteoporosis. The results showed that the risk of vertebral fracture was reduced by 65% within 18 months of treatment. Nonvertebral fracture risk was reduced by 50%. Teriparatide increases bone mass and improves bone architecture.
Drugs with other mechanisms of action
Vitamin D derivatives
Calcitriol, the active metabolite of vitamin D, has some stimulatory effects on the osteoblasts, the bone forming cells. There is evidence that calcitriol reduces the risk of vertebral fractures in postmenopausal osteoporosis.
Two large phase III trials have shown that a daily oral dose of 2 g of strontium ranelate reduces the risk of vertebral fractures by 40-50%, and also reduces the risk of nonvertebral fractures. Hip fracture risk was decreased by 36% in elderly women with osteoporosis. Strontium ranelate increases BMD markedly. Its mechanism of action is not fully understood, but appears to involve a dual effect with a mild reduction of bone resorption and a maintenance or mild increase of bone formation.
Nutrition and lifestyle play an important role in osteoporosis prevention and treatment. Other factors, like fall prevention techniques, or hip protectors to reduce the impact in case of a fall, are also very important.
Calcium, vitamin D, and protein
Calcium (0.5-1 g/day) and vitamin D (800 IU/day) supplements have been shown to reduce the risk of hip fracture in studies in elderly women living in nursing homes (who are often vitamin D deficient), but not always in studies carried out in the healthy, non-institutionalised elderly. In addition, all studies having shown the efficacy of bisphosphonates, Serms, calcitonin, teriparatide or strontium ranelate were performed with patients adequately supplemented with calcium and vitamin D. No demonstration of the anti-fracture efficacy of these compounds has been obtained without concomitant supplementation in calcium and vitamin D. Sufficient protein intake is mandatory to help maintain muscle function and bone mass.
Regular weight-bearing exercise has been shown to help maintain and build up bone mass. The stronger muscles, better balance and agility to which exercise contributes can also help in fall prevention. The type of exercise should be tailored to the individual's needs and abilities. People with osteoporosis must take special care when exercising to reduce the risk of fracture due to impact or falls.
Psychological and practical support
Rehabilitation following fractures, strategies for the prevention of falls, and psychological and practical support are important components of treatment. In addition to the practical help offered by many osteoporosis patient support groups, such groups can also be of great help in alleviating the feelings of isolation and depression experienced by many patients with severe osteoporosis.