Osteoporosis (suspected)

• Osteoporosis is characterised by low bone mass and micro architectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in the risk of fracture 1
• The World Health Organization (WHO) has designated the first decade of the 21st century, as the 'Decade of Bone and Joint Diseases' recognising the importance of osteoporosis as a public health issue 2
• The cost to Australian economy of osteoporosis is estimated to be $7.4 billion dollars per year 4
• Osteoporosis is often described as a 'silent disease', with the radiological prevalence of the disease far in excess of diagnosis and active treatment to prevent further bone loss and future fracture 4
• Risk factors associated with osteoporosis 1
  • Family history - parent or sibling
  • Early menopause
  • Hypogonadism
  • ≥3 months glucocorticoids (at prednisolone ≥7.5mg)
  • Coeliac disease / malabsorption disorders
  • Rheumatoid arthritis
  • Primary hyperparathyroidism
  • Hyperthyroidism
  • Chronic kidney or liver disease
  • Androgen deprivation therapy
  • Recurrent falls
  • Breast cancer on aromatase inhibitors
  • Treatment with antiepileptic medications
  • Low body weight
  • HIV and its treatment
  • Major depression / SSRI treatment
  • Type 1 and type 2 diabetes mellitus
  • Multiple myeloma / monoclonal gammopathy
  • Organ or bone marrow transplant
• There are various fracture risk calculators in existence. In Australia a locally developed calculator based on the Dubbo Osteoporosis Epidemiology Study 18 can be found by following this link. Another commonly used tool is the Fracture Risk Assessment Tool (FRAX) which has been developed by WHO. The calculator for this can be found by following this link. The Garvan tool has been shown to be more accurate than the FRAX tool 19
• At any age, women are considered to have approximately double the risk of a fracture compared with men. However once a man sustains a fragility fracture his risk of a subsequent fracture is higher than that of an equivalent woman 19
• For T scores of -1.0, -2.0 and -3.0 the relative risk of fracture increases by a factor of 1.7, 3.4 and 6.8 respectively 20

• The current "gold standard" for the diagnosis of osteoporosis 1,20
• DEXA is superior to other techniques for assessing BMD because of its 9,20
  • Low precision error
  • Low radiation dose and short scan time (approximately one-tenth of that of a standard chest radiograph)
  • Capacity to measure multiple skeletal sites
• Limitations of DEXA include 1
  • Hip replacement precludes measurement of hip BMD
  • In the spine, degenerative disease cause falsely elevated results owing to features such as osteophytes and compression fractures
  • Measurements of different DEXA machines may vary considerably for the same individual (it is important to have follow-up scans on the same machine if possible)
• Results are expressed as Z or T scores, defined as the number of standard deviations (SDs) from the age and sex matched control means (Z score) and from the mean value in a 30 year old (T score) 1
• The T score can be expressed as the following: 21
  (measured BMD minus young adult BMD) / (young adult standard deviation)
• When interpreting serial DEXA scans it is best to consider the bone density change over time (g/cm2) rather than T scores as T score calculations are age dependent 20
• Based on bone densitometry, measured by DEXA and the T score, the World Health Organization classifies the patients into three categories 6,7
  • Normal bone density: T score greater than -1
  • Osteopenia (low bone mass): T score between -1 and -2.5
  • Osteoporosis: T score less than -2.5
• For information for consumers about DEXA InsideRadiology

• Patients with a Z score less than 1.5 with risk factors should be evaluated for secondary causes of osteoporosis. The following biochemical investigations can be obtained depending on the clinical context 4,20
• Full blood count
• Erythrocyte sedimentation rate
• Calcium
• Creatinine
• Total alkaline phosphatase and albumin
• Thyroid stimulating hormone
• Protein electrophoresis
• Anti-tissue transglutaminase antibody or anti-endomysial antibody
• Parathyroid hormone
• 25-hydroxy vitamin D
• Secondary causes of osteoporosis can include 20
• Hyperthyroidism
• Hyperparathyroidism
• Renal failure
• Hyper / hypocalcicuria
• Coeliac disease
• Hyperthyroidism
• Haematologic disorders
• Exogenous medications (e.g. phenytoin, glucocorticoids, tacrolimus, cyclosporine, methotrexate, lithium, proton pump inhibitors)
• Androgen deprivation therapy

The general principles of treatment in osteoporosis centre around the following 19

• Address and correct any underlying conditions that may be contributing to the development and progression of osteoporosis (e.g. hypogonadism, myeloma, hyperparathyroidism, Cushing’s syndrome, etc)
• Despite limited evidence there should be a consideration of lifestyle aspects (e.g. encouraging weight-bearing exercise, dietary intake of calcium, cease smoking, evaluate and rectify possible causes of falls, etc)
• Osteoporosis specific pharmacotherapy
• Vitamin D and calcium supplementation if inadequate
• Falls prevention strategies

The following table contains recommended management and follow up depending on the BMD T score, risk factors and presence or absence of a minimal trauma fracture 1

• The following points should be addressed in those patients who do not have an indication for DEXA scan or whose scan result does not qualify them for osteoporotic treatment
  • General lifestyle advice
  • Advise to stop smoking and consume minimal alcohol
  • Evaluate and rectify possible causes of falls
  • Advocate a regular weight bearing or strengthening exercise program
  • Exposure to indirect sunlight for 15 minutes, four to six times a week
• Ongoing monitoring for osteopenia/osteoporosis. Regularly monitor height as a loss of height of 2.5cm is a surrogate marker for osteoporosis. Plain radiographs of the spine should be considered for an asymptomatic vertebral fracture 10

• The main high risk groups for whom BMD measurement should be considered include
  1. Patients over 70 years of age
  2. Suspected vertebral fracture where fracture is confirmed then referral for DEXA should be made
  3. Patients with minimal trauma fracture
  4. Patients over 50 with the following risk factors
  • Family history - parent or sibling
  • Early menopause
  • Hypogonadism
  • ≥3 months glucocorticoids (at prednisone ≥7.5mg)
  • Coeliac disease / malabsorption disorders
  • Rheumatoid arthritis
  • Primary hyperparathyroidism
  • Hyperthyroidism
  • Chronic kidney or liver disease
  • Androgen deprivation therapy
  • Recurrent falls
  • Breast cancer on aromatase inhibitors
  • Treatment with antiepileptic medications
  • Low body weight
  • HIV and its treatment
  • Major depression / SSRI treatment
  • Type 1 and type 2 diabetes mellitus
  • Multiple myeloma / monoclonal gammopathy
  • Organ or bone marrow transplant
• Items above highlighted in blue currently have medicare rebates associated with them
• Guidelines or evidence based reviews on the indications for BMD testing have been published by many organisations. Those of the International Society for Clinical Densitometry for bone density testing are the most comprehensive and clinically useful 5
  1. Women Aged 65 years and older
  2. Postmenopausal women under age 65 with risk factors for osteoporosis
  3. Men aged 70 years and older
  4. Adults with fragility fracture
  5. Adults with disease or condition associated with low bone mass or bone loss
  6. Adults taking medication associated with low bone mass or bone loss
  7. Anyone being considered for pharmacological osteoporosis therapy
  8. Anyone being treated for low bone mass to monitor treatment effect
  9. Anyone not receiving therapy in whom evidence of bone loss would lead to treatment
  10. Women discontinuing estrogen therapy

Go to FRAX 

Go to Garvan