Bone mineral density over 96 weeks in adults failing first-line therapy randomized to raltegravir/lopinavir/ritonavir compared with standard second-line therapy

Objective: To compare bone mineral density (BMD) changes over 96 weeks in adults virologically failing standard first-line therapy, randomized to raltegravir plus lopinavir/ritonavir (RAL + LPV/r) or conventional 2-3 nucleoside/nucleotide reverse transcriptase inhibitors [N(t)RTIs] + LPV/r second-line therapy.

Methods: Participants underwent dual-energy x-ray absorptiometry at baseline and weeks 48 and 96 to measure total hip and lumbar spine BMD. Analyses were adjusted for gender, body mass index, and smoking. Linear regression was used to compare between-group differences, logistic regression for low BMD (hip or spine Z-score ≤ 22) incidence, and multivariate linear regression to determine predictors of BMD change. This work represents the extension and final results of the previously published initial 48 weeks of the study.

Results: The population included 210 adults from 5 middle-income countries: 52% females, 52% Asians, 43% Africans, mean age, 39 years (SD, 8 years). In the 2-3 N(t)RTI group (vs. RAL), BMD reduction was greater at the spine (mean change, 24.9% vs. 23.5%; adjusted difference, 21.9%; 95% confidence interval: 23.3 to 20.5%, P = 0.009) and hip (24.1% vs. 22.2%; 21.9%; 23.4 to 20.4; P = 0.012). BMD decrease was greatest at 48 weeks with stabilization to week 96. Overall, low BMD occurred in 15 participants (7.9%), with no between-group differences. Independent predictors for bone loss included lower body mass index (regression coefficient: hip, 20.18% and spine, 20.26% per 1 kg/m2), longer tenofovir exposure (hip, 20.74% and spine, 21.0% per year), greater change in CD4+ to week 12 (hip, 25.11% per 10-fold higher), and higher baseline HIV-RNA (spine, 20.7% per 10-fold higher).

Conclusions: Over 96 weeks, there was greater BMD decrease with 2-3 N(t)RTI + LPV/r compared with RAL + LPV/r; the relative decrease at the spine was greater than the hip. BMD decreases with second-line antiretroviral therapy largely occurred in the first 48 weeks with stabilization, but no recovery thereafter.