Reassurance for HIV-positive women about short-term risk of bone loss

Short-term rates of bone loss are similar in younger HIV-positive and HIV-negative women, US investigators report in a study published in the online edition of the Journal of Acquired Immune Deficiency Syndromes.

Although HIV-positive women had lower bone mineral density in the lower spine and neck on entry to the study, they had similar rates of bone loss during follow-up. Moreover, HIV treatment was not a risk factor for bone loss.

“Our results provide some reassurance that short-term bone loss is modest in the majority of premenopausal, weight stable HIV+ women”, write the investigators.

Several studies have reported that HIV-positive women have an increased risk of low bone mineral density. There is also information that suggests that bone loss is accelerated in this group in the period immediately after antiretroviral therapy is started. However, bone mineral density appears to be stable in people who are taking established HIV treatment.

To gain a better understanding of the progression of and risk factors for bone loss in women with HIV, investigators from the US Women’s Interagency HIV Study (WIHS) designed a longitudinal study that monitored bone loss in 100 HIV-positive and 68 HIV-negative women. All were pre-menopausal.

Bone mineral density was measured in the lumbar spine and femoral neck using DEXA scans. Measurements were obtained on entry to the study and then during a follow-up period lasting an average of 2.5 years.

Information was also gathered on the incidence of fractures and on the prevalence of factors that could potentially be associated with bone loss. This included traditional risk factors such as age, weight, drug use and smoking, and HIV-related factors such as CD4 cell count, viral load and the use of antiretroviral therapy.

At the start of the study, the HIV-positive women were significantly older (mean, 40 years vs. 36 years, p < 0.001) and were more likely to be infected with hepatitis C virus (31% vs. 12%, p = 0.004). Antiretroviral therapy was being taken by 59% of the HIV-positive women when they entered the research.

Bone mineral density at baseline was 5% lower amongst the HIV-positive women.

Factors associated with low bone mineral density in these women included low body weight (p = 0.003) and alcohol use (p = 0.005). There was no association with CD4 cell count, progression to AIDS, or the duration or type of antiretroviral therapy.

Amongst women with HIV, there was a small but significant annual decrease in bone mineral density during follow-up in both the lumber spine (-1.9%, p = 0.001) and femoral neck (-1.9%, p = 0.02). Modest falls in bone mineral density in these sites were also observed in the HIV-negative controls. When the investigators compared the rate of bone loss between HIV-positive and HIV-negative women they found that there was no significant difference.

Nor did the investigators find that women with HIV had an increased risk of rapid bone loss (above 3% per year).

When the researchers restricted their analysis to HIV-positive women, they found that taking HIV treatment did not increase the risk of bone loss. Nor did they find any association between treatment with tenofovir (Viread, also in the combination pills Truvada and Atripla) a drug sometimes associated with bone problems.

In statistical analysis that controlled for potentially confounding factors, vitamin D deficiency (p = 0.011), and use of opioids (p = 0.04) were both significantly associated with bone loss in women with HIV.

The overall incidence of fractures was comparable between the HIV-positive and HIV-negative women.

“Premenopausal HIV+ women with antiretroviral therapy exposure had slightly lower bone mineral density than comparable HIV- women but experienced similar short-term bone loss”, conclude the investigators.