It is recommended to assess the risk of fragility fracture and low BMD in all patients with HIV infection.⁹ Important risk factors for fracture include:

1. Previous history of fragility fracture
2. Glucocorticoid therapy for more than 3 months
3. High risk of falls

Those with these risk factors should be assessed with dual-energy X-ray absorptiometry (DXA).  In others, age-specific recommendations apply.⁹ Australian osteoporosis guidelines state that all individuals who sustain a fracture following minimal trauma should be considered to have a presumptive diagnosis of osteoporosis.  A presumptive diagnosis can also be made if a spinal compression fracture is found.¹ The presence of a vertebral fracture is a risk factor for further fractures developing¹⁰ and a loss of height or more than 3 cm indicates the need to assess for a vertebral fracture with a standard spine X-ray.¹ The factors that should be considered when assessing the risk of osteoporosis are presented in Table 1.

Table 1.   Risk factors for Osteoporosis

• History of minimal trauma fracture
• Height loss ≥3 cm and/or back pain suggestive of vertebral fracture
• Female
• Older than 70 years of age
• History of falls
• Parental history of hip fracture
• Premature menopause or hypogonadism
• Prolonged use of glucocorticoids (at least three months cumulative prednisone or equivalent ≥7.5 mg per day)
• Use of other medications that cause bone loss
• Conditions or diseases that lead to bone loss
• Low body weight Low muscle mass and strength
• Low physical activity or prolonged immobility
• Poor balance
• High alcohol intake
• Energy, protein or calcium undernutrition
• Vitamin D insufficiency
• Smoking

 Assessing absolute fracture risk

 Absolute fracture risk can be calculated using algorithms such as the Garvan Fracture Risk Calculator (GFRC)  (www.garvan.org.au/bone-fracture-risk) or the Fracture Risk Assessment Tool (FRAX) (www.shef.ac.uk/FRAX).  These assessment tools take into account multiple risk factors in addition to any history of fracture and BMD to calculate an absolute fracture risk. When calculating the FRAX score, HIV infection should be listed as a secondary cause.⁹

 DXA screening

 Australian osteoporosis guidelines suggest the following groups be screened by DXA:

1. Younger than 50
   1. Minimal trauma fracture as individual case decision
2. 50 to 60 years
   1. Vertebral fracture
   2. Minimal trauma fracture
   3. Disease or condition associated with bone loss
   4. Medications increasing bone loss
3. 60 to 70 years
   1. Vertebral fracture
   2. Peripheral minimal trauma fracture
   3. Disease or condition associated with bone loss
   4. Hip fracture in a parent
   5. Underweight
   6. Multiple falls
   7. Immobility

Recommendations for DXA scanning in patients with HIV infection

 Men aged 40-49 years or premenopausal women aged 40 years or older who have intermediate or high-risk stratification by FRAX (>10% 10-year risk of major osteoporotic fracture)

1. All post-menopausal women
2. All men 50 years of age or older
3. Adults with fragility fracture regardless of age

In addition to these indications, current European Guidelines suggest DXA if there is a high risk of falls or clinical hypogonadism.¹¹ Recent US guidelines recommend baseline BMD testing in postmenopausal women and in anyone over 50 years of age.¹³ When interpreting DXA results, T-scores should be used for postmenopausal women and men 50 years of age or older and Z-scores for those less than 50 years of age.⁹ To assess efficacy of treatment, DXA scans should be repeated in 2 years.  If BMD is stable, then longer intervals can be considered. Conversely, in those at high risk of fracture, shorter intervals between DXA scans may be appropriate.¹ The optimal interval of time for repeating a BMD after the initial screening BMD in the non-osteoporotic population is unknown.  OREP guidelines, using data from the general post-menopausal population and the HIV positive population, advise timing a repeat BMD based on the T-score of the initial BMD⁹.  For patients with a T-score of -2 to -2.49 a repeat BMD at 1-2 years is advised and for a T-score of -1.01 to 1.99 a repeat at 5 years.  For patients with a normal BMD (T-score >-1) an interval of up to 15 years can be used.  If during the recommended interval the patient has a fragility fracture or a new risk factor for osteoporosis develops then the repeat BMD should be performed earlier.  A specific Medicare rebate for DXA scans for HIV is not available in Australia.

Screening for secondary causes of osteoporosis and assessment of falls risk

 Once the diagnosis of osteoporosis is established, secondary causes should be looked for.  The most common causes are presented in Table 2.

Table 2 Secondary causes of Osteoporosis

• Vitamin D deficiency
• Hyperparathyroidism
• Hyperthyroidism
• Hypogonadism
• Cushing’s syndrome
• Phosphate wasting
• Idiopathic hypercalciuria
• Coeliac disease
• Multiple myeloma

If a history of falls is obtained or the patient reports poor balance, a falls assessment should be conducted.^15,16 This involves a medical history, a review of medications that may be contributing, and a physical examination that includes neurological and functional assessment.  An occupational home therapy assessment and podiatry review may be warranted.¹