Osteoporosis is a bone disease that affects many people worldwide. It is a chronic (long-lasting) disease and can be debilitating or life-threatening. Osteoporosis has had a substantial economic impact on the Canadian healthcare system. The cost of hip fractures alone in Canada is expected to be $2.4 billion by 2041. In this review, we will discuss the top drug-based osteoporosis treatment options.
We will begin by describing osteoporosis and how it is diagnosed.
What is osteoporosis?
Osteoporosis is a bone disorder defined by compromised bone strength. It causes a loss of bone mass and deterioration of bone tissue. This can lead to fragile bones that are easily fractured. The disease occurs when bones lose mineral content more quickly than it can be replaced, causing them to weaken. This weakness increases the risk of bone fractures.
Osteoporosis is most common in people 50 years and older, but can affect any age group. Two million Canadians suffer from osteoporosis, and the disease is more common in women than in men. Like other cells in the body, bone cells are constantly being broken down and regenerated. Until young adulthood, bone mass builds more quickly than it is broken down and bone strength increases. Peak bone mass is usually reached between 25 and 30 years of age. At this point, bone growth begins to slow. Osteoporosis occurs when bones can no longer replace minerals quickly enough and bones become thin and porous.
The most common fractures caused by osteoporosis are at the wrist, spine, shoulder, and hip. Fractures can lead to severe pain and other symptoms. However, there are usually no symptoms until a fracture occurs. Osteoporosis is the leading cause of hip fractures. Patients who experience hip fractures are more at risk for recurring fractures.
What causes osteoporosis and how is it diagnosed?
Age, sex, diet, and physical activity can affect the risk of developing osteoporosis. Bone loss occurs more quickly in women approaching menopause due to hormonal changes. Drug use and presence of other medical conditions can also increase the risk of developing the disease. Osteoporosis caused by another condition is referred to as secondary osteoporosis and contributes to loss of bone mass.
Because symptoms do not appear until a bone fracture occurs, the disease often goes undiagnosed. Osteoporosis is diagnosed by measuring bone density and other indicators of bone strength. Bone mineral density is typically measured with a DXA scan. Other diagnostic tools such as an X-ray can also help diagnose the disease.
The goals of osteoporosis treatment are to reduce the risk of bone fracture and limit decreases in bone mineral density. Osteoporosis treatment options include lifestyle changes and drug-based therapies. Below, we discuss the top ways to treat osteoporosis using drug-based therapies.
Top drug-base osteoporosis treatment options
Bisphosphonates are a class of drugs that slow the rate of bone deterioration. They work by binding to the bone surface and slowing down the action of osteoclasts, which are cells that are responsible for the breakdown of bone tissue. This preventative action leads to higher bone density and lowers the risk of fracture. Bisphosphonates are considered the first-line treatment for osteoporosis.
Four bisphosphonates are currently approved as osteoporosis treatment options in Canada: alendronate, etidronate, risedronate, and zoledronic acid. Clinical trials have shown that alendronate, risedronate, and injectable zoledronic acid are effective at lowering the risk of spinal and hip fractures. They can cause a number of side effects including abdominal pain, gastrointestinal issues and nausea. Instances of bone, joint, and muscle pain have also been reported, though some side effects may only be temporary. Bisphosphonates can be used to treat osteoporosis in both men and women.
2. Hormone therapy
Estrogen, progesterone, and testosterone are hormones that are important for maintaining bone health in men and women. After menopause, women produce much less estrogen and progesterone which can lower bone density. Hormone therapy raises the level of sex hormones in the body to the lowest amount needed to prevent bone loss. Hormone therapy can also help with the symptoms of menopause.
Clinical trials have shown that hormone therapy can lower the risk of fracture in postmenopausal women. The incidence of fracture was less at the hip, spine, and other areas of the body. However, hormone therapy is only recommended as a short-term treatment due to adverse effects of prolonged use. After five years, the risk of heart disease, stroke, and some forms of cancer can increase. Short-term side effects include headaches, weight gain, and skin irritation among others.
Other otherosteoporosis treatment options should be explored before using hormone therapy.
3. Other drug-based options
Raloxifene is sometimes used as an alternative to hormone therapy in postmenopausal women. It is a member of the selective estrogen receptor modulator (SERM) drug class, and has a similar effect to estrogen in the bones. Raloxifene helps mitigate the effects of bone mineral loss in the body. Side effects of the drug include muscle cramping, hot flashes, and an increased risk of blood clots.
An antibody therapy called denosumab is a new form of treatment for osteoporosis. It works by binding to receptors involved in the breakdown of bone tissue and prevents osteoclasts from forming. Interrupting osteoclast formation lowers the rate of bone loss in the body.
Denosumab has been shown to reduce the risk of spinal, hip, and other fractures in postmenopausal women. Men at high risk of fracture can also benefit from the therapy. Adverse effects can include muscle pain, itching, and skin irritation. Denosumab is a first-line therapy for osteoporosis but may be more expensive than other osteoporosis treatment options.
Teriparatide is another new form of treatment for osteoporosis. Teriparatide is a synthetic version of parathyroid hormone (PTH), which regulates calcium metabolism and is important for bone health. It is chemically similar to PTH, and increases the rate of calcium absorption in the bones. It also activates cells responsible for building bone mass in the body (osteoblasts), leading to higher bone density and strength.
Teriparatide has been shown to lower the risk of spinal and non-spinal fractures, excluding hip fractures. It is often used in patients with severe osteoporosis, especially those who developed the disease from the use of glucocorticoid medications. Teriparatide can also decrease the pain of spinal fractures. Adverse effects include dizziness, nausea, and muscle cramping.
Calcitonin is a hormone that can also benefit symptoms of osteoporosis. Calcitonin restricts the activity of osteoclasts which lowers the amount of calcium released from bones. Studies have shown that it helps maintain or improve bone density, and also lowers risk of spinal fractures. Nasal sprays containing calcitonin were removed from the market in 2013 due to increased risk of cancer with long-term use. Other forms are available, though the therapy is rarely used. There is limited data on the benefits of calcitonin for non-spinal fractures. It is not considered a first-line treatment for osteoporosis.
Sodium fluoride is a compound that activates bone-building cells (osteoblasts). It has been shown to improve bone mineral density in the spine and hip. However, the ability of sodium fluoride to prevent osteoporotic fractures is not well understood. Some studies have shown that it reduces spinal and non-spinal fractures at low doses. Sodium fluoride may have strong adverse effects including gastrointestinal upset. Further clinical trials are needed to determine if sodium fluoride is effective for treating osteoporosis.
4. Natural health products
Natural health products have become a popular alternative therapy for many health conditions including osteoporosis. Evidence on the effectiveness of these products is limited and should be confirmed with larger clinical trials.
Dehydroepiandrosterone (DHEA) is a steroid hormone produced by the adrenal glands. DHEA levels begin to decline naturally in the mid-twenties. It has been linked to a number of health conditions including osteoporosis. Some studies have shown that DHEA improves bone mineral density, but data is not consistent between trials.Side effects of DHEA can include hair loss, insulin resistance, abdominal pain, and changes in menstrual patterns.
Non-steroid compounds found in plants have also been used to treat osteoporosis. Phytoestrogens, such as isoflavones, have a similar chemistry to estrogens. The isoflavones genistein and daidzein bind to estrogen receptors and produce low-level activity at these sites. There is limited data on how phytoestrogens benefit osteoporosis and bone density. Side effects include constipation, diarrhea, shortness of breath, sleep disturbances, and joint pain. More research is needed to understand the role of phytoestrogens as osteoporosis treatment options.
Ipriflavone is a synthetic compound that has been suggested to improve bone density. It is derived from isoflavones and acts similarly to estrogen in the human body. However, it does not cause the same adverse effects as estrogen hormone therapy. Some studies have shown that ipriflavone improved bone mineral density, while others noted no noticeable changes; data on bone fractures is limited. Adverse effects of ipriflavone include abdominal pain, nausea, diarrhea, and constipation.
Vitamin K is a group of fat soluble vitamins found in many dietary sources; it is also produced by gut bacteria. The group includes Vitamin K1 (phytonadione) and Vitamin K2 (menaquinone).
Low levels of vitamin K have been associated with bone fractures and lower bone mineral density in people with osteoporosis. Some studies have shown that it improves bone density and reduces fractures in osteoporosis patients. However, results varied depending on the ethnicity of the patients treated. There is some evidence that Vitamin K2 reduces osteoporotic fractures and it was more commonly used in studies than Vitamin K1. Vitamin K2 was well tolerated with gastrointestinal upset reported in some cases.
Black cohosh is a medicinal plant root used to treat some hormone-related symptoms in women such as premenstrual syndrome and menopausal symptoms. How black cohosh works in the body is not yet clear. It may increase some measures of bone formation but results have not been confirmed by clinical trials.
Calcium and Vitamin D
Calcium and vitamin D are the only two natural health products that have been recommended as osteoporosis treatment options. Both calcium and vitamin D are important for bone strength and muscle function. Consuming the recommended daily calcium allowance can reduce bone loss and risk of fracture. Vitamin D helps the body to absorb calcium which promotes bone health. We discuss these and other natural osteoporosis treatment options in more detail in this article: Five ways to treat osteoporosis without medication.
Osteoporosis is a long-term disease that compromises bone health. A number of drug-based treatment options exist for osteoporosis, including bisphosphonates, antibody therapies, hormonal therapies, and others. Aside from calcium and vitamin D, natural health products have not been approved as osteoporosis treatment options.
Patients with osteoporosis may have different medical needs depending on their age, sex, and gender, and should discuss this with their doctor when considering drug-based therapies.
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