Stable or increasing bone mineral density in HIV-infected patients treatedwith nelfinavir or indinavir

Background and objectives: To determine the factors contributing to changes in bone mineral density (BMD) over time in HIV-infected patients receiving highly active antiretroviral therapy (HAART). Methods: Analyses of lumbar spine BMD in 183 male Caucasian participants in the Western Australian HIV Cohort study, comprising a longitudinal analysi s of data from 54 patients on stable HAART regimens, and a cross-sectional analysis comparing data from 131 protease inhibitor (PI)-treated patients a nd 52 PI-naive (including 28 antiretroviral treatment-naive) patients. Results: Average lumbar spine BMD remained stable or increased over the tim e frame considered. Although there was no evidence of a change of average B MD over time in patients receiving nelfinavir (P = 0.92), there was evidenc e of increasing bone density in the indinavir group (average increase, 0.31 z-score per year; P < 0.001). Lower initial z-scores in the longitudinal a nalysis were significantly associated with lower pre-HAART BMI (P = 0.003), consistent with results of the cross-sectional analysis in which lowest BM I prior to initial dual X-ray absorptiometry scan was associated with decre ased BMD (P = 0.02, overall group). Although PI therapy was also associated with decreased BMD in a univariate analysis of the cross-sectional data (P = 0.04), this effect was abrogated in a multiple linear regression analysi s (P = 0.11) with lowest BMI remaining significant (P = 0.04). Conclusions: We found no evidence, overall, of accelerated bone loss in pat ients treated with nelfinavir- or indinavir-containing HAART regimens, and propose that indinavir therapy may be associated with an increase in bone m ineral density over time. Pre-HAART BMI was an independent and powerful det erminant of an individual's initial z-score in the longitudinal analysis, a nd adjustment for this effect in a cross-sectional analysis abrogated the a ssociation between P1 therapy and decreased lumbar spine z-score. (C) 2001 Lippincott Williams & Wilkins.