Determinants of Low Bone Mineral Density in Virologically Suppressed HIV-Infected Patients

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 248-267-Osteoporosis II
Clinical
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-262
Naim M Maalouf*1, Henning Dreschler2, James B Cutrell3, Song Zhang3 and Roger Bedimo2
1UT Southwestern Medical Center, Dallas, TX, 2University of Texas Southwestern Medical Center and VA North Texas Health Care System, 3University of Texas Southwestern Medical Center
Background: Osteoporosis is increasingly reported in aging HIV-positive patients, although the determinants of low bone mineral density (BMD) in this population remain unclear. This study assessed the determinants of low BMD in virologically suppressed HIV-infected men.

Methods: This prospective, cross-sectional study recruited 64 male volunteers with HIV who were virologically suppressed on highly active anti-retroviral therapy (HAART) and 34 non-infected controls. Subjects with known osteoporosis or CKD stage 3 or worse were excluded. Subjects underwent BMD testing by DXA scan and measurement of fasting serum receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG), gonadal hormones, serum insulin-like growth factor-1 (IGF-1), IGF-binding protein 3 (IGFBP-3), and the bone turnover markers (BTM) serum C-telopeptide (CTX), osteocalcin (OC), and bone-specific alkaline phosphatase (BSAP).

Results: The HIV group was slightly older (57 vs. 52 years, p=0.017). BMI was in the overweight range but lower in the HIV group (27.5 vs. 29.8 Kg/m2, p=0.039). At the time of evaluation, 83% of HIV-infected patients were on tenofovir and 48% on protease inhibitors. After adjusting for age, race and BMI, the HIV group had significantly lower femoral neck and total hip BMD, Z-score and T-score (p<0.05 for all). Compared to controls, the HIV group exhibited significantly higher serum CTX (0.58±0.29 vs. 0.41±0.15 ng/mL), OC (21.5±8.9 vs. 15.5±5.1 ng/ml), BSAP (34.2±11.5 vs. 26.4±9.1 U/L) and OPG (4.4±1.4 vs. 3.8±1.0 pM), and lower serum RANKL/OPG ratio (34±31 vs. 54±35) (p<0.05 for all). HIV and Controls had similar serum total testosterone (4.1±2.1 vs. 3.9±1.1 nM), estradiol (35±11 vs. 37±11 pg/mL), LH (5.9±3.7 vs. 5.4±1.7 IU/L), IGF-1 (147±45 vs. 141±41 ng/ml), and IGFBP-3 (3.4±1.1 vs. 3.4±0.6 mg/L) (p>0.3 for all). Within the HIV-infected population, femoral neck BMD was negatively associated with BTM (r= -0.30 for BSAP, r= -0.25 for OC), but not with gonadal hormones or IGF-1.There was a tendency towards lower BMD in tenofovir users (p=0.03-0.09 depending on site), but no difference in BMD between protease inhibitor users and non-users.

Conclusions: HIV-infected men on HAART exhibit significantly lower BMD than non-HIV infected men. The lower BMD persists after adjustment for age, race and BMI, is not explained by changes in serum IGF-1 or gonadal hormones, and is associated with higher bone turnover markers but lower RANKL/OPG ratio.

Nothing to Disclose: NMM, HD, JBC, SZ, RB

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: The study is funded by Veterans Administration MERIT grant I01 CX000418–01A1.