Bone Loss Differs Depending on ART Rx

November 12, 2015

Here's why you need to keep bone disease in mind when choosing an antiretroviral regimen for your patients with HIV -- and guidance about selecting therapy.

HIV patients at risk for bone loss may be better off taking a nucleoside or nucleotide reverse transcriptase inhibitor (NtRTI)-sparing regimen rather than one containing tenofovir, according to a new study.

The results suggest that clinicians should keep bone disease in mind when choosing an antiretroviral regimen for their HIV patients, especially since many patients are living longer.

Osteopenia, osteoporosis and low bone mineral density (BMD) frequently occur in HIV patients, noted the researchers, led by Dr. Jose I. Bernardino, HIV Unit, from Hospital Universitario La Paz in Madrid. Antiretroviral therapy (ART) leads to losses of BMD in ART-naïve patients, but NtRTI-sparing regimens can ameliorate these effects.

The researchers assessed the 96-week loss of BMD in 146 ART-naïve, HIV-1-infected patients. They assessed longitudinal changes in BMD at the total hip, femoral neck, and lumbar spine and changes in biomarkers of bone turnover and inflammation.

The study included 70 patients who were treated with regimens containing the integrase inhibitor raltegravir (NtRTI-sparing) and 76 patients treated with tenofovir-emtricitabine regimens.

At week 48, the mean percentage loss in BMD in the lumbar spine and total hip was greater in the standard group than in the NtRTI-sparing group. At the femoral neck BMD losses were also greater in the standard group than in the NtRTI-sparing group. At 96 weeks, the standard group showed greater BMD losses at all three sites than the NtRTI-sparing group.

Seven new fractures occurred during the trial, two in the NtRTI-sparing group and five in the standard group.

Most bone turnover markers were also increased at week 48, and the changes in bone turnover biomarkers were generally significantly greater in the standard group than in the NtRTI-sparing group.

There were no differences in new cases of osteopenia or osteoporosis or in changes in inflammatory biomarkers.

In conclusion, the researchers stated: "The clinical usefulness of NtRTI-sparing regimens is unclear, especially after new tenofovir combinations, including tenofovir-alafenamide, become available. Compared with tenofovir disoproxil fumarate, tenofovir alafenamide has less effect on glomerular function, tubular function and bone mineral density. The increased safety of tenofovir alafenamide is encouraging, but whether these differences would translate into real clinical benefit, although highly probable, remains to be proven. Until this combination becomes widely available, we think that NtRTI-sparing regimens could be of use, especially for populations with a high risk of bone disease after initiation of ART."

They pointed out that a raltegravir-based regimen was associated with significantly less loss of BMD than a standard regimen containing tenofovir disoproxil fumarate, and “might be a treatment option for patients at high risk of osteopenia or osteoporosis who are not suitable for NtRTIs such as abacavir or tenofovir alafenamide.”