High incidence of reduced bone density found in HIV positive people

Metabolic complications have been observed in individuals living with HIV and using antiretrovirals, including several studies that have reported reduced bone mineral density (BMD).

A research letter published in AIDS (August 17th) submitted by Antonia Moore and colleagues from the Chelsea and Westminster Hospital, London concludes with a possible association between protease inhibitors (PI) and BMD.

BMD is determined using a dual energy X-ray absorptiometry (DEXA) scan and the results categorised by T-score. By WHO definition T-scores between 1 and 2.5 below the mean (peak bone density for an individual of that age and gender from the general population) is defined as osteopenia and >2.5 as osteoporosis.

In this study of 105 patients (median age 40 years, 71% male, 75% Caucasian), 71% were found to have reduced BMD with, 58% in the osteopenia range and 13% in the osteoporosis range.

Neither age, gender, race, smoking, CD4 count or HIV RNA level at the time of the scan, BMI, self reported lipodystrophy or length of time being HIV positive were significantly associated with reduced BMD. Low baseline CD4 count (<50 cells/mm3) at baseline, history of AIDS, prior antiretroviral use other than with an NNRTI, and ever having been treated with a PI was associated with reduced BMD in univariate analysis but none of these associations persisted in multivariate analysis.

Despite not remaining statistically significant after adjustment for multivariate analysis, the authors suggest a possible association between PI use and reduced BMD in HIV positive people although they add that ‘as all patients on therapy also receive nucleoside analogues, it is possible that the effect may be a consequence of nucleosides and PI combined.’ They also state that the benefits of using PIs are undisputed, but that the ‘continuing emergence of possible toxic side-effects serves further to complicate the ongoing debate regarding when to start antiretroviral treatment and which agents to use.’

Comment

The authors feel that screening for reduced BMD in the HIV population cannot be justified and include the reason that ‘Early knowledge of this diagnosis may be harmful to patients who already have to cope with a chronic incurable condition.’ And they continue ‘Notably, for postmenopausal women (known to be at risk of osteoporotic fracture and for whom treatments are of confirmed benefit) the consensus is that large-scale screening cannot be justified’.

This is a contentious issue and arguments against screening may not usefully be extrapolated from other populations.