Diagnosis>Organ System>

CLINICAL

• Osteoporosis in HIV+ pts 3-4x more common than in general population.
• Increased prevalence may be due in part to high prevalence of risk factors, including low body weight, hypogonadism, smoking, alcohol use, steroid use.
• Role of ART unclear. ART initiation associated with 2-3% loss in bone mineral density (BMD) in first 6 mos in multiple studies. Unclear if due to medication effect or by-product of viral suppression and/or immune reconstitution. Longitudinal studies of treated HIV+ pts generally show stable BMD over time.
• Specific ARVs not clearly implicated in pathogenesis, although bone loss with TDF slightly more pronounced than with d4T.
• BMD explains approximately 50% of fracture risk in general population,perhaps less in HIV+ pts. Bone quality also important but difficult to assess.
• Fracture risk in HIV+ pts not adequately assessed to date

DIAGNOSIS

• Dual x-ray absorptiometry (DXA) of hip and spine used to assess BMD.
• Osteoporosis defined as T-score < -2.5 (i.e., BMD > 2.5 standard deviations lower than a young, gender-matched control population).
• Osteopenia defined as T-score between -1 and -2.5.
• Definitions using T-scores created for post-menopausal women. Utility in other populations (pre-menopausal women and men) controversial. Some advocate for use of Z-score (number of SD lower than age, and gender-matched population) in these populations.
• In general population, fracture risk increases ~2x for each SD decrease in BMD.
• Universal screening of HIV+ pts not recommended, except for post-menopausal women > 65 yrs as recommended in general population. Screening also reasonable in men and pre-menopausal women with gonadal dysfunction, wasting, or steroid use.

TREATMENT

• Laboratory evaluation for significant osteopenia or osteoporosis: PTH, calcium, phosphate, TSH, testosterone (men) and 25-OH vitamin D.
• In selected cases, consider celiac disease, multiple myeloma, idiopathic hypercalciuria and Cushing's syndrome.

• Calcium 1200 to 1500 mg/dplus vitamin D 400 to 800 IU/d
• Weight-bearing exercise (30 minutes at least 3 days/wk)
• Cessation of heavy alcohol use and smoking

• Consider drug treatment for those with T-score < -2.5 or fragility fracture. For osteopenia, consider therapy based on other risk factors and the degree of bone loss. If no treatment, repeat DXA in 1-2 years
• Bisphosphonates (risedronate [35 mg q wk], alendronate [70 mg q week], ibandronate [150 mg q month]) considered first-line and have been shown to safe and efficacious in HIV+ pts. Annual IV zoledronate [5 mg q year] useful if PO therapy not tolerated. Duration of therapy unclear.
• Raloxifene (60 mg q day) is reasonable alternative or adjunctive treatment to bisphosphonates in postmenopausal women.
• Teriparatide (parathyroid hormone analog) stimulates new bone formation and should be considered in those not responsive to bisphosphonates (20 mcg per day subcutaneously). A course of 18-24 mos without concomitant bisphosphonates is recommended. Has not been specifically evaluated in HIV+ pts

Drug Comments

REFERENCES