6th IAS Conference On HIV Pathogenesis, Treatment and Prevention


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MOAB0101 - Oral Abstract

Osteoporotic fracture risk associated with cumulative exposure to tenofovir and other antiretroviral agents

Presented by Roger Bedimo (United States).

R. Bedimo1,2, S. Zhang2, H. Drechsler1,2, P. Tebas3, N. Maalouf2

1VA North Texas Health Care System, Medicine, Dallas, United States, 2UT Southwestern Medical Center, Medicine, Dallas, United States, 3University of Pennsylvania, Medicine, Philadelphia, United States

Background: Decreased bone mineral density is increasingly reported in the aging HIV-positive population. While tenofovir exposure has been associated with decreased bone mineral density, it remains unclear whether it´s associated with increased risk of osteoporotic fractures (OF).
Methods: Patients with any OF (defined as wrist, vertebral or hip fracture) occurring after HIV diagnosis were identified by ICD9 code in the Veterans Affairs´ Clinical Case Registry from 1984 to 2009. Pharmacy records were used to calculate cumulative exposure to different antiretroviral drugs prior to the first OF event or end of follow-up; controlling for race, age, tobacco use, diabetes, and body mass index (BMI).
Results: 56,660 HIV-infected patients (98.1% male; mean age: 45.0 years) contributed 305,237 patient-years of follow-up (median: 4.5 years/patient). During this period, 951 patients sustained at least one OF(124 vertebral, 486 wrist and 341 hip). The following table summarizes the risk of OF by type of antiretroviral therapy (ART):

Drug or Drug CategoryPY of ExposureHazard Ratio per Year of Exposure (95% Confidence Interval; p value)
  Univariate AnalysisMulti-variable Model 1Multi-variable Model 2
Tenofovir (TDF)460621.08 (1.02-1.15; 0.010)1.04 (0.98-1.11; 0.168)1.01 (0.93-1.10; 0.771)
Abacavir (ABC)242510.99 (0.93-1.05; 0.737)0.95 (0.89-1.02; 0.157)0.95 (0.88-1.02; 0.141)
ART with boosted protease inhibitors (rPI)327861.09 (1.03-1.16; 0.003)1.06 (0.998-1.126; 0.057)1.07 (0.99-1.16; 0.091)
ART with NNRTI492800.99 (0.95-1.04; 0.715)0.96 (0.91-1.01; 0.077)0.98 (0.92-1.04; 0.420)
ART with thymidine analogues704721.01 (0.98-1.05; 0.496)0.97 (0.94-1.01; 0.121)0.98 (0.93-1.04; 0.554)
[Cumulative antiretroviral exposure and OF risk]

Model 1: Controlling for CKD, are, race, tobacco use, diabetes and BMI
Model 2: Controlling Model 1 variable + concomitant exposure to other antiretrovirals.
Other factors independently associated with increased risk of OF included older age (HR=1.478), non-Black race (HR=1.614), tobacco use (HR=1.491) and BMI < 20 (HR=1.480).
Conclusion: Cumulative exposure to TDF and rPI was associated with a modest increase in OF risk, which was no longer significant after controlling for traditional OF risk factors.

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