osteoporosis

see also

• bone physiology
• calcium
• vitamin D
• bisphosphonates
• sacral insufficiency fracture (SIF) - osteoporotic fracture
• MJA 2010 Position Statement - Treatment for osteoporosis in Australian residential aged care facilities: consensus recommendations for fracture prevention

• in Australia, lifetime risk of osteoporosis in those over 50yrs age is 42% for women and 27% for men.
• affects 2 million Australians
• 20,000 hip fractures per year in Australia - increasing by 40% each decade
  • about 25% die within 12 months
  • 15-25% require long term care

• prolonged corticosteroids Rx such as doses of oral prednisolone greater than 7.5mg per day for 3 months or more.
• conditions with excess corticosteroids secretion
• male hypogonadism
• Turner syndrome
• amenorrhoea lasting > 6 months before the age of 45 years
• primary hyperparathyroidism
• chronic liver disease
• chronic renal disease
• proven malabsorption disorders
• rheumatoid disorders
• conditions associated with thyroxine excess

• postmenopause
• FH / genetic factors
  • elderly mice showed both reduced levels of Men1 and increased activity of senescence-related genes in osteoblasts ¹⁾
• slight body build (BMI < 18)
• previous low trauma fracture
• smoking
• high alcohol intake
• other medications that cause bone loss:
  • anticonvulsants
  • loop diuretics ⇒ calciuresis
  • long term heparin
  • those that induce menopause such as gonadotrophin releasing hormone agonists (GnRH agonists)
  • thyroxine in the elderly - a BMJ study in 2011 showed dose related fracture risk of 2.5-3.5x in those over 70yrs taking > 0.044mg/day thyroxine.

• used to confirm Dx of osteoporosis and estimates severity of bone loss
• can be used to determine response to Rx
• lower radiation dose compared to other methods
• results are given a T scores which are statistical scores relating to population standard deviations of 20 yr olds:
  • T score > -1.0 SD = normal
  • T score between -1.0 and -2.5 SD = osteopaenia
  • T score less than or equal to -2.5 SD = osteoporosis
  • T score less than or equal to -2.5 SD with 1 or more fragility fractures = severe osteoporosis
• Monash Med Centre - DEXA scan patient information sheet (pdf)

• low calcium intake
• vitamin D deficiency
• oestrogen deficiency states
• hyperthyroidism
• 5% of Caucasian adults with osteoporosis will have coeliac disease as the cause
• in men, test for presence of hypogonadism and if present Rx with testosterone when necessary

• see calcium

• see vitamin D
• apparently no short term (5yr) benefit on reducing fractures by taking vit D supplements in those over 50yrs without risk factors ²⁾

• bisphosphonates can reduce progression of osteoporosis by inhibiting the resorption of bone
• regarded as 1st line Rx used in conjunction with calcium and vitamin D supplementation.
• C/I include oesophageal diseases
• see bisphosphonates

• may be useful, particularly in women < 60yrs age (esp. in those concerned of breast cancer risk with hrt) or where bisphosphonates can't be used.
• has similar risk of DVT as for HRT but does not relieve symptoms of menopause
• only subsidised for post-menopausal women with PH osteoporotic fracture
• C/I in men, premenopausal women, pregnancy and those with PH DVT

• active form of vitamin D can be used as a 3rd line Rx for osteoporosis although evidence for its efficacy is less robust and it requires adequate calcium intake and risks hypercalcaemia, thus requires monitoring of serum calcium levels.
• only subsidised for post-menopausal women with PH osteoporotic fracture

• Although parathyroid hormone (PTH) increases the release of calcium from bone, intermittent use stimulates osteoblasts more than osteoclasts. By mimicking this effect of parathyroid hormone, teriparatide, an amino acid sequence similar to parathyroid hormone (PTH) aims to stimulate bone formation in patients with osteoporosis.
  • Aust Presc 2004
• listed on PBS in 2009 for Rx of severe established osteoporosis (BMD T-score of -3.0 or less) in those at very high risk of fracture, who develop symptomatic fracture(s) despite at least 12 months of continuous antiresorptive Rx. Requires initialisation by a specialist (Auth. req.)
• Rx duration limited to 18 months as risk of osteosarcoma, and thus Rx requires informed consent.
• daily sc injection

• may be considered for postmenopausal women who are considered at low risk for cardiovascular disease or breast cancer

• denosumab (Prolia)
  • humanised monoclonal antibody which binds RANKL blocking the interaction with its receptor on the surface of osteoclasts which then inhibits development and activity of osteoclasts, leading to decreased bone resorption and increased bone density
  • studies suggest it reduced vertebral fractures, #NOF by around 50% compared with placebo incidence, but appears to cause more eczema, cellulitis, myalgias, arthralgias, bone pains, urinary issues, alopecia, flatulence and perhaps a risk of immunocompromise with mildly higher rates of infections (URTI, diverticulitis) and malignancies
  • may cause hypocalcaemia
  • 1 in 1000 develop osteonecrosis of the jaw (1 in 200 if > 10yrs Rx) and it can also occur after stopping treatment.
  • may cause lichenoid drug eruptions in the mouth
  • some people have developed unusual fractures in their thigh bone
  • introduced in Aust in 2010, long acting s/c injection usual dose 60mg once per six months

• Level 4 - Western Centre For Health Research and Education Sunshine Hospital
• To make a booking please fax your referrals to 03 8395 8258 or call 03 8395 8246/8119.
• The unit is open for scanning on Tuesday and Wednesday between 9:00am-5:00pm.

• MJA March 2009 - Position statement - Calcium and bone health: position statement for the Australian and New Zealand Bone and Mineral Society, Osteoporosis Australia and the Endocrine Society of Australia
• Aust Prescr 2008 - Corticosteroid-induced osteoporosis and fractures
• Aust Fam Phys 2004 - Osteoporosis - diagnosis, treatment and management
• Aust Prescr 1997 - Outcomes of the Australian Osteoporosis Consensus Conference
• Consensus statement. The prevention and management of osteoporosis. Australian National Consensus Conference 1996. Med J Aust 1997;167(Suppl):1S-15S.
• MJA 2009: Vertebroplasty appears no better than placebo for painful osteoporotic spinal fractures, and has potential to cause harm. Buchbinder et al