Hormone therapy

Hormone therapy at the time of menopause may be beneficial for protecting bones. The Women's Health Initiative Trial (published July 2002 and October 2003) has shown that continuous combined oral hormone therapy as oestrogen plus progestin, does reduce the incidence of fractures at the hip and vertebrae in postmenopausal women.^73,74 However, long-term oral oestrogen-progestin hormone therapy, particularly in older women, is associated with other risks of heart disease, breast cancer and deep vein thrombosis.⁷⁴ Hence, although hormone therapy has beneficial effects on bone health, it should be prescribed primarily for the short-term treatment (less than 5 years) of menopausal symptoms in women who are progressing through the menopausal transition. The Women's Health Initiative Trial of oestrogen alone in women who have had a hysterectomy has also shown a reduction in fracture risk along with no increase in heart disease or breast cancer, but a small increase in the risk of stroke in women aged 50 to 79 years.^101,102

The use of hormone therapy solely for fracture prevention is not generally recommended. However, in some instances this may be the best available option and thus some women may elect to use hormone therapy for this purpose. This needs to be done in consultation with the treating physician and with the woman understanding the risks and benefits of this therapy.

Bisphosphonates

Bisphosphonates are a class of drugs, which function to decrease bone loss. They have been extensively studied in postmenopausal osteoporotic women and have been shown to reduce fracture risk in this population. There is a paucity of data pertaining to the effects of these compounds in terms of fracture prevention in people with osteopaenia.

The currently available bisphosphonates in Australia, which are recommended for the treatment of Osteoporosis are Fosamax (alendronate), Fosamax plus D (alendronate and cholecalciferol- vitamin D3), Actonel (risedronate), Actonel Combi ( risedronate and calcium carbonate), Actonel Combi D (risedronate, calcium carbonate and vitamin D) and Didrocal (etidronate & calcium carbonate).

Both alendronate and risedronate have been found to reduce the incidence of vertebral and hip fractures.^75,76 These drugs also reduce the risk of fracture at other sites in the body. The effects of these drugs on reducing the risk of fracture usually starts within 6 - 12 months of commencing therapy.

These medications are generally well tolerated. They have been associated with side effects of gastro-oesophageal reflux, abdominal discomfort and ulceration of the oesophagus. Ulceration of the oesophagus is one of the side effects that is most concerning. Hence, these medications must be taken first thing in the morning on an empty stomach, with a full glass of water and the individual needs to remain either sitting upright or standing for the next 30 minutes. After this time, normal activities and eating can be resumed. The incidence of oesophageal ulceration is extremely low when these medications are taken correctly.⁷⁷ These medications can be taken either daily or once weekly. There is an increasing trend for prescribing these medications once weekly as it improves compliance and it is likely to further reduce the incidence of gastrointestinal upset with these medications.⁷⁷ It is advisable that these medications are used cautiously in those with significant reflux oesophagitis and those with a hiatus hernia. These drugs are not well absorbed, hence it is important to take them on an empty stomach. It is also recommended not to take calcium at the same time of day as the bisphophonates is taken, as calcium may interfere with the absorption of the bisphosphonates.

In general randomised controlled trials of postmenopausal osteoporotic women have shown that bisphosphonates increase lumbar spine BMD by approximately 4.5 - 8.3% and femoral neck BMD by approximately 1.6 - 3.8% after 3 to 4 years of treatment.⁷⁹

Combination preparations of Bisphosphonates

Fosamax plus D, Actonel Combi and Actonel Combi D have both recently become available. Fosamax plus D® provides the added benefit of a weekly dose (2,800 IU)  of vitamin D; equivalent to a daily dose of 400 IU. (Refer to vitamin D  section). Actonel Combi®  is also a combination medicine combining 7 tablets per pack: one actonel tablet once/week and 6 calcium carbonate 1250mg tablets for the other days of the week. Actonel Combi D® has been PBS listed in 2008. It contains 35mg of Actonel and six powdered sachets of calcium carbonate and vitamin D. The sachets are mixed with water and drank. (See also calcium supplements).   

Didrocal (etidronate and calcium) is administered in a somewhat different way to the other medications. This preparation is administered cyclically because when given continuously a reduction in bone formation may occur. For 2 weeks the active tablet etidronate is taken twice daily. Following this period a calcium tablet is then taken once daily for the next 11 weeks. This cycle is then repeated. This medication is generally well tolerated and does not have the problems with side effects of the upper gastrointestinal system such as heartburn or oesophageal ulceration. There may be side effects of diarrhoea or nausea. Generally this drug has been found to be effective in increasing bone mineral density and may reduce the incidence of vertebral fractures.⁷⁸ This medication is probably best suited to women with osteoporosis of the spine.

In order for these medications to be effective in increasing bone mineral density and reducing the likelihood of fracture, women need to ensure that they have an appropriate intake of calcium either through diet or supplements and that they also have adequate vitamin D levels. For women taking Didrocal, there is no need to take additional calcium supplements, as these are already included in this preparation. There still may be a requirement for additional Vitamin D supplementation if the measured Vitamin D levels are low.

Bisphosphonates are primarily recommended for women who have osteoporosis as defined on a bone DEXA study and/or a history of an osteoporosis related fracture. In this setting the cost of these medications is subsidized by the Australian PBS.

There is also evidence to suggest that these medications may also prevent fractures in women with osteoporosis as defined by a T score of - 2.5 or less who do not have a history of fracture.⁸⁰ Since April 2007, bisphosphate therapy with Fosamax®, Fosamax plus D®, Actonel®, Actonel Combi® and Actonel Combi D® is available on the PBS for patients with osteoporsis aged 70 years and over who have a bone density ≤-3, even in the absence of fracture.

There are also data that the use of bisphosphonates in individuals on long-term corticosteroid therapy (eg prednisolone) can prevent and treat corticosteroid-induced osteoporosis.^81-85 However, as of November 2003, risedronate has received RPBS listing for the prevention of corticosteroid-induced osteoporosis. This medication can be used in individuals who have not had a history of a fragility fracture. To qualify for this medication, the individual must be on 7.5 mg or greater of prednisolone or an equivalent per day for at least 3 or more months and have a documented BMD T score of < -1.0.

There are many unresolved issues with regards to the use of these medications. One issue is in regards to how long therapy with these drugs should be given. There are few studies using these medications beyond 7 years of therapy, although there is one recently published study with alendronate, which was used for 10 years.⁸⁶ This study continued to show safety of aledronate, with ongoing BMD improvement. There was no fracture data efficacy provided in this study for aledronate use up to 10 years. Most physicians would recommend using these medications until such a time that there is improvement in bone mineral density measurements and for about 5-7 years. Hopefully as more studies become available and the duration of the studies are longer, then further recommendations for long-term use can be made. Another issue is in regards to using these medications to prevent osteoporosis. This is not currently recommended, as studies to date have not shown a benefit in terms of preventing fractures in women who have osteopaenia.⁸⁰

Intravenous Bisphosphonates

If women are unable to tolerate oral bisphosphonates, there is the option to have intermittent intravenous infusions of either Pamidronate or Zoledronic acid. Zoledronic acid is effective in increasing bone density in women with postmenopausal osteoporosis and only requires a once yearly 15 minute infusion.⁸⁷ However, there are currently no data available on this agent in regards to its effects on reducing fracture rates. This therapy is still undergoing clinical evaluation. Intravenous Pamidronate is generally given as a 30 mg infusion over 2 - 3 hours every 3 months. However, there are few randomised controlled trials evaluating the effects of this therapy in postmenopausal women with osteoporosis and the studies that have been done have been on small numbers of women.^88,89 Intravenous Pamidronate has been found to increase BMD.^88,89 Both Zoledronic acid and Pamidronate intravenous infusions may be associated with side effects of fever, arthralgia and myalgia and neither is available on the PBS for the treatment of osteoporosis.

Zolindrinic acid has been associated with osteonecrosis of the jaw (see above).

 Raloxifene

This medication is known as a selective oestrogen-receptor modulator. It acts at some sites in the body like oestrogen but at other sites of the body it functions as an anti-oestrogen. In bone it works as an oestrogen and leads to an increase in bone mass. In the breast and uterus it works as an anti-oestrogen and therefore does not stimulate the breast or uterine lining. Due to its anti-oestrogen effects in the breast, it reduces the incidence of breast cancer by approximately 70%, particularly in women with elevated estradiol levels.^90,91

Primarily this medication has been shown to reduce the incidence of vertebral fractures. The evidence for this medication having a significant effect on fractures at other sites of the body is lacking.⁹²

The side effects of this therapy include hot flushes. This therapy is therefore problematic for premenopausal women and women who are currently going through the menopausal transition, as it may exacerbate menopausal symptoms. This therapy is best reserved for postmenopausal women who have gone through the menopausal transition. Other side effects of this therapy are leg cramps and a slightly increased risk of deep vein thrombosis.⁹¹ Hence, women who are on this medication need to consider stopping this therapy if they are going to be immobile for sometime, such as during long airline flights or during hospital admission. The medication can be resumed once mobility is regained. Any woman who has significant risk factors for a clotting disorder should not be prescribed raloxifene.

In order for this therapy to be effective it is essential that women have adequate vitamin D levels and adequate dietary calcium intake. It may be necessary to have supplements of calcium and vitamin D if measured vitamin D levels are low or dietary calcium intake is inadequate.

Strontium ranelate