The mainstay of primary prevention in osteoporosis is to detect and treat the disease before fractures occur.
Fracture prevention lies in predicting those at high risk for fracture based on assessments of BMD together with consideration of risk factors for fracture. These risk factors include BMI, smoking status, alcohol consumption, corticosteroid exposure, concurrent rheumatological condition, family history of hip fracture, and secondary causes of osteoporosis.1
|Secondary contributing factors|
|Adverse events of drug therapy|
Osteoporosis has been defined on the basis of BMD assessment at the lumbar spine and femoral neck by dual energy x-ray absorptiometry (DXA), which is the most widely validated technique for measuring BMD.3,4 The World Health Organization (WHO) criteria classifies BMD as normal, osteopenia (low BMD), or osteoporosis based on T-scores, which refer to the number of standard deviations (SDs) a patient’s BMD lies below either the reference BMD for a young, healthy, gender-matched reference population (T-score) or an age- and gender-matched reference population (Z-score); the latter being a preferable measure for individuals <50 years old.5
|Population||Score at the hip or spine|
|Normal||Postmenopausal women and men aged ≥50 years||T score ≥–1.0|
|Osteopenia||Postmenopausal women and men aged ≥50 years||T-score –1 to –2.49|
|Osteoporosis||Postmenopausal women and men aged ≥50 years||T-score ≤–2.5|
|Abnormal||<50 years old*||Z-score ≤–2.0|
*Diagnosis should not be made on the basis of BMD testing alone
European AIDS Clinical Society Guidelines recommend that HIV-infected patients with >1 major risk factor for low BMD should undergo DXA scanning. These risk factors include post-menopausal women, men over the age of 50, patients with symptomatic hypogonadism, patients with a history of fragility fracture and those with significant steroid exposure.
Figure 1.* Algorithm for the screening, assessment, management, and monitoring of bone disease in PLWHIV.1
*Abbreviations: FN - femoral neck; LS - lumbar spine; TH - total hip
However, although low BMD based on DXA criteria is prevalent in younger PLWHIV, it is uncertain if these DXA values correspond to an increased risk of fractures, particularly in those under the age of 50. Caution should therefore be used when interpreting results from DXA in the HIV-infected population, particularly in young men.
As well as establishing a diagnosis of low BMD, DXA can also be used to monitor the effect of interventions over time.
The FRAX® tool has been developed by the WHO to combine BMD readings with classical risk factors for osteoporosis and fracture in order to provide a more accurate fracture risk. The FRAX algorithms provide a 10-year probability of hip fracture and the 10-year probability of a major osteoporotic fracture (spine, forearm, hip or shoulder). It is country specific and should only be used in patients >40 years old, as the tool utilizes real-life data from population-based cohorts around the world that have a limited age range (>40 years). The European AIDS Clinical Society (EACS) Guidelines state that the risk of fracture should be assessed biannually. FRAX may underestimate the fracture risk in people living with HIV (PLWHIV);7 using HIV as a secondary risk factor may help identify those patients at high risk of osteoporosis even if DXA results are not available.
As most fractures result from falls, the risk factors for falling can be evaluated using the FRAT, which was developed and validated in the non-HIV infected population. It comprises three sections – falls risk status, risk factor checklist and action plan.