Considerations before treating osteoporosis

Before starting drug therapy for osteoporosis, consider the possibility of a secondary cause of bone loss or fracture (see Risk factors for minimal-trauma fracture for a list of conditions that can cause bone loss), and factors that can interfere with bone mineral density (BMD) measurement. Up to 30% of postmenopausal women and 50% of men with osteoporosis have a secondary cause.

Osteoporosis in premenopausal women and young men (less than 50 years) is uncommon and its presence should prompt investigation for a secondary cause. Seek specialist advice to guide management.

Optimising the management of a secondary cause can minimise fracture risk and avoid unnecessary treatment with antiresorptive drugs. However, specific osteoporosis treatment may still be required despite management of a secondary cause.

Patient history and clinical examination can help to identify secondary causes of bone loss. Features that suggest that a secondary cause may be responsible for bone loss or fracture include:

  • a Z-score lower than –2.0
  • severe osteoporosis (eg T-score below –3.0)
  • multiple fractures
  • bone loss or minimal-trauma fracture in a young patient or a patient with no other apparent risk factors
  • history of a medical condition or use of a drug that affects bone homeostasis or density (see Risk factors for minimal-trauma fracture)
  • unusual persistence of pain at the fracture site
  • features of systemic illness (eg weight loss)
  • unusual fracture patterns or radiological findings.

Investigations to detect common secondary causes may be reasonable; consider testing:

  • serum calcium concentration
  • serum phosphate concentration
  • serum alkaline phosphatase concentration
  • serum 25-hydroxyvitamin D concentration
  • serum thyroid stimulating hormone concentration
  • liver biochemistry
  • kidney function.

If a specific secondary cause is suspected, other tests can be performed as indicated; for example:

  • serum parathyroid hormone concentration
  • urinary calcium excretion
  • serum and urine protein electrophoresis
  • erythrocyte sedimentation rate
  • coeliac serology
  • serum testosterone concentration in men
  • serum follicle stimulating hormone and estradiol concentrations in women
  • 24-hour urinary free cortisol test, overnight dexamethasone suppression test or late-night salivary free cortisol test.

Also consider the possibility of a metabolic bone disease other than osteoporosis (eg osteomalacia), particularly in patients with a malabsorption disorder or kidney disease.

Specialist input is required for management of osteoporosis in patients with a secondary cause of osteoporosis, women of child-bearing potential and pregnant women, post-transplant osteoporosis and patients with osteoporosis and chronic kidney disease (particularly creatinine clearance less than 35 mL/min).