Medical Chronicle May 2017 | Page 26

CLINICAL OSTEOPOROSIS BISPHOSPHONATE TREATMENT IN OSTEOPOROSIS Osteoporosis is a leading contributor of fractures worldwide, causing more than 8.9 million fractures annually. Pretreatment evaluation Before commencing bisphosphonate therapy, patients should be evaluated to detect potentially remediable causes of or other contributing factors to osteoporosis. This evaluation includes assessment for hypocalcaemia, vitamin D deficiency, and renal impairment by measuring serum: • Calcium • 25-hydroxyvitamin D (25[OH]D) • Creatinine. For both oral and IV bisphosphonates, correction of hypocalcemia and/or vitamin D deficiency is necessary prior to administration. Osteoporosis affects an estimated 200m women worldwide (approximately 1/10th of women aged 60, 1/5th of women aged 70, 2/5ths of women aged 80, and 2/3rds of women aged 90). One in three women and one in five men over 50 will experience an osteoporotic fracture. Additionally, 61% of all osteoporotic fractures occur in women. It has been predicted that the incidence of hip fracture is expected to increase by 310% in men and 240% in women by 2050. The economic toll of osteoporosis is expected to significantly increase. Indeed, it has been estimated that there is a 40% lifetime risk for fractures affecting the hip, forearm and vertebrae (similar to the risk for cardiovascular disease), with nearly 75% of these types of fractures occurring in patients aged 65 years age and above. Osteoporosis has been shown to account for more days spent in the hospital than diabetes, heart attacks or breast cancer. It is also a major cause of disability, which has been shown to be greater than that caused by cancer (except lung cancer) and comparable to or greater than disability from rheumatoid arthritis, asthma and high blood pressure related heart disease. The overall mortality within the first 12 months after a hip fracture is approximately 20%, being higher in men than women. Men make up 20%-25% of all hip fractures, and have an estimated 30% lifetime risk of experiencing an osteoporotic fracture when over 50, similar to the lifetime risk of developing prostate cancer. Fragility fractures are 26 MAY 2017 | MEDICAL CHRONICLE the primary cause of hospitalisation and/or death for US adults ≥age 65 and above. Furthermore, 44% of nursing home admissions are due to fractures. It is obvious that osteoporosis is extremely common and this condition leads to disability, costs and even death. BISPHOSPHONATE THERAPY Bisphosphonates are a class of drugs that are used to prevent bone loss demineralisation (weakening or destruction). These have been used since the 1970s, but technological developments in recent years have continued to reduce the frequency of dosage and made other stronger forms of the drugs available. Osteoporosis is caused by the cumulative effect of bone resorption in excess of bone formation. Bisphosphonates inhibit bone resorption with relatively few side effects. As a result, they are widely used for the prevention and treatment of osteoporosis. Bisphosphonates are also used in the management of hypercalcemia, Paget disease, and a number of malignancies, including multiple myeloma, breast cancer, and prostate cancer. These topics are all reviewed separately in the appropriate topic reviews. The treatment of osteoporosis consists of lifestyle measures and pharmacologic therapy. Lifestyle measures include adequate calcium and vitamin D, exercise, smoking cessation, counseling on fall prevention, and avoidance of heavy alcohol use. These mea