Bone Disease

Bone Disease: Screening and Diagnosis

Osteoporosis

  • Postmenopausal women and men age ≥ 50 years with BMD T-score ≤ -2.5 at hip or lumbar spine
  • Premenopausal women and men age < 50 years with BMD Z-score ≤ -2 at hip or lumbar spine and fragility fracture

Characteristics

  • Reduced bone mass and altered bone quality
  • Increased risk of fractures in persons with HIV
  • Asymptomatic until fractures occur
  • Aetiology multifactorial
  • Loss of BMD observed with ART initiation (mainly during 1st year)
  • Greater loss of BMD with initiation of certain ARVs(i)

Risk factors

  • Consider classic risk factors(ii) and estimate fracture risk using FRAX in people ≥ 40 years
  • Consider DXA in any person with ≥ 1 risk of(iii):
    1. Postmenopausal women 
    2. Men ≥ 50 years 
    3. High risk for falls(iv)
    4. Those with high fracture risk (> 20% 10-year major osteoporotic fracture risk based on FRAX assessment without DXA)
    5. History of low impact fracture
    6. Clinical hypogonadism (symptomatic, see Sexual Dysfunction)
    7. Oral glucocorticoid use (minimum 5 mg/d prednisone equivalent for > 3 months) 

Diagnostic tests

  • DXA scan: In those with classic risk factors who require DXA, where feasible consider DXA scan prior to ART initiation or soon after initiation
  • Add DXA result to FRAX® to refine fracture risk prediction (http://www.shef.ac.uk/FRAX)
    - May underestimate risk in persons with HIV
    - Consider using HIV as a cause of secondary osteoporosis(v)
    - Trabecular Bone Score (TBS: derived from DXA scan result) may also be added to FRAX® risk prediction.
  • Rule out causes of secondary osteoporosis if BMD low(vi)
  • Vertebral fracture assessment on lateral DXA images or lateral spine X-rays (lumbar and thoracic) if osteoporosis on DXA, or significant height loss (≥ 4 cm) or kyphosis develops. (DXA-based vertebral fracture assessment can be used as an alternative to lateral spine X-ray)

 

  1. Greater loss of BMD observed with initiation of regimens containing TDF and some PIs. * Additional loss and gains in BMD observed with switch to and away from TDF-containing ARV regimens, respectively. Clinical relevance to fracture risk not determined. TAF is associated with less bone loss than TDF
    Consider replacing TDF if:
    • Osteoporosis / progressive bone loss
    • History of fragility fracture
    * There are limited data on use of PIs and changes after their replacement.

  2. Classic risk factors: older age, female gender, hypogonadism, family history of hip fracture, low BMI (≤ 19 kg/m2), smoking, physical inactivity, history of low trauma fracture, alcohol excess (> 3 units/day), glucocorticoid exposure (minimum prednisone 5 mg/qd or equivalent for > 3 months)
  3. If BMD T-score normal (≥ -1), repeat after 3-5 years in risk groups 1, 2 and, 3; no need for re-screening with DXA in risk groups 4, 5 and 6 unless risk factors change and only rescreen group 7 if glucocorticoid use ongoing
  4. Falls Risk Assessment Tool (FRAT), see https://www2.health.vic.gov.au/ageing-and-aged-care/wellbeing-and-participation/healthy-ageing/falls-prevention/falls-prevention-tools
  5. If including BMD within FRAX, entering yes in the secondary cause box will not be considered in the FRAX algorithms, as it is assumed that secondary osteoporosis affects fracture risk solely through BMD. However, if the contribution of HIV infection to fracture risk is partially independent of BMD, fracture probability may be underestimated by FRAX
  6. Causes of secondary osteoporosis include hyperparathyroidism, vitamin D deficiency, hyperthyroidism, malabsorption, hypogonadism or amenorrhoea, diabetes mellitus, and chronic liver disease

  7. Use of tenofovir disoproxil fumarate (TDF) is associated with cases of renal phosphate wasting. For diagnosis and management of renal phosphate wasting, see Indications and Tests for Proximal Renal Tubulopathy (PRT)

Osteomalacia

Characteristics

  • Defective bone mineralisation
  • Associated with vitamin D deficiency
  • Increased risk of fractures and bone pain
  • Vitamin D deficiency may cause proximal muscle weakness

Risk factors

  • Dark skin
  • Dietary deficiency
  • Avoidance of sun exposure
  • Malabsorption
  • Obesity
  • Renal phosphate wasting(vii)

Diagnostic tests

  • Measure serum calcium, phosphate, alkaline phosphatase and 25(OH) vitamin D, see Vitamin D Deficiency. If deficient or insufficient, check PTH levels and consider vitamin D replacement if clinically indicated, see Vitamin D Deficiency
  ng/mL nmol/L
Deficiency <10 <25
Insufficiency <20 <50

    Osteonecrosis

    Characteristics

    • Infarct of epiphyseal plate of long bones resulting in acute bone pain
    • Rare but increased prevalence in persons with HIV

    Risk factors

    • Low CD4 count
    • Glucocorticoid exposure 
    • IVDU
    • Alcohol
    • Blood coagulation disorders

    Diagnostic tests

    • MRI