Risk of Osteoporotic Fractures Associated with Cumulative Exposure to Tenofovir and Other Antiretroviral Agents Roger Bedimo, MD; Song Zhang, PhD; Henning Drechsler, MD; Pablo Tebas, MD; Naim Maalouf, MD

Osteoporotic Fractures among HIV- Infected Patients: Role of ART  Decreased bone mineral density is increasingly reported in the aging HIV-positive population.  Odds of osteoporosis are elevated in HIV-infected vs. uninfected 1,2, and in ART users vs. non-users 1  Tenofovir exposure was shown to be associated with a significantly greater decrease in bone mineral density than stavudine 3, and abacavir 4  The risk of osteoporotic fractures (OF) associated with cumulative (PY) exposure to tenofovir vs. other antiretroviral agents has never been explored 1 Brown and Qaqish AIDS 2006,20: ; 2 Triant et al, JCEM. 2008,93: Gallant et al., JAMA. 2004;292(2): McComsey G. JID 2011;203(12):

Methods: Data Source, Predictors and Outcome Measures Data Source: Veterans Affairs’ Clinical Case Registry; HIV patients in pre-HAART (’88-’95) and HAART eras (’96-’09). Predictors: –Antiretroviral exposure: PY of exposure to NRTIs (TDF, ABC, AZT or D4T), NNRTI, boosted PI. –Age, Race, Smoking, BMI, type 2 diabetes, HCV co-infection (by ICD-9 codes or antibody +), Chronic kidney disease: Estimated GFR<60 by MDRD Gender not included in the model; The population is >98% male. Outcome: Incident osteoporotic fracture defined as any: –Vertebral fractures (ICD-9 codes through 805.7), Hip fractures (820.0 through 820.9), or Wrist fractures (814.0, 814.1, and 813.5)

Results: Study Population, Treatment Exposure and Events Two separate analyses were conducted, including: 1.All patients enrolled in CCR from 1988 to Patients enrolled in the HAART era only: from 1996 to Cumulative exposure to each separate ARV or ARV class, from first administration to censure date: –1) development of the first OF episode ; 2) discontinuation of the ARV; 3) last recorded patient encounter; 4) December 31 st, 2009 (date of censure of the dataset). Cox survival models of association of ARV exposure & OF: –1) Univariate analysis; –2) MV Model 1: Controlling for CKD, age, race, tobacco use, DM, BMI & HCV; 3) MV Model 2: Controlling for Model 1 variables + concomitant exposure to other ARVs.

Results: Study Population, Follow-Up Time and Events Entire Period: (n =56,660) HAART Era Only: (n =32,439) Number of Patients with ART Exposure (%) 39,277 (69.4%)27,107 (83.6%) Total PY of Observation 305,237191,258 Total PY of ART Exposure 164,414122,364 Vertebral Fractures Wrist Fractures Hip Fractures All Osteoporotic Fractures* *defined for this study as first vertebral, wrist or hip fracture during follow-up

Risk Factors among Patients with and without Osteoporotic Fracture Baseline Characteristics Total (n =56,660) Fracture (n =951) No Fracture (n =55,709) P-value Age in Yrs; median ( SD) 44 (10)46 (10)44 (10)P< % Male 98 P=0.91 % Whites P< % Smokers P< % Diabetes* P< % BMI< P< % HCV Positive P< *Classified only by ICD-9 codes. Laboratory values not extracted

Age-adjusted Rates of Osteoporotic Fractures (Entire Cohort) ≥70 Age at Cohort Entry (Years) Fracture Rate (per 1,000 patient-years) Vertebral Hip Wrist Total General population 1 1 Data from Triant V, et al., JCEM 2008;93: 3499–3504

Factors Predicting Osteoporotic Fracture in HIV Patients FactorsHazard Ratio (95% Confidence Interval; p value) Univariate AnalysisMulti-variable Analysis Cumulative ART Use (per year) 1.05 (1.01 – 1.10; p=0.02)0.99 (0.95 – 1.04; p=0.77) CKD (eGFR <60)1.48 (1.04 – 2.09; p=0.03)1.05 (0.72 – 1.53; p = 0.79) White Race1.76 (1.46 – 2.13; p < )1.88 (1.54 – 2.30; p< ) Age (per 10 year increase) 1.51 (1.39 – 1.63; p <0.0001)1.50 (1.37 – 1.64; p< ) Tobacco Use1.25 (1.06 – 1.47; p=0.01)1.31 (1.09 – 1.56; p=0.003) Diabetes1.27 (1.05 – 1.53; p=0.01)1.10 (0.90 – 1.34; p=0.34) BMI < (1.29 – 2.00; p<0.0001)1.48 (1.18 – 1.87; p=0.007) HCV Co-infection1.43 (1.21 – 1.69; p<0.0001)1.49 (1.25 – 1.77; p< )

Antiretroviral Exposure and Risk of Osteoporotic Fractures: MV Model 1: Controlling for CKD, age, race, tobacco use, diabetes and BMI; MV Model 2: Controlling for Model 1 variables + concomitant exposure to other ARVs. Drug or Drug Category PY of Exposure Hazard Ratio per Year of Exposure (95% Confidence Interval; p value) Univariate AnalysisMulti-variable Model 1Multi-variable Model 2 Tenofovir (TDF)46, ( ; <0.001) 1.06 ( ; 0.079) 1.06 ( ; 0.106) Abacavir (ABC)24, ( ; 0.989) 0.96 ( ; 0.245) 0.96 ( ; 0.224) Thymidines (AZT or D4T) 94, ( ; 0.199) 0.96 ( ; 0.311) 0.99 ( ; 0.520) boosted PI (rPI) 41, ( ; 0.015) 1.04 ( ; 0.142) 1.03 ( ; 0.349) NNRTI59, ( ; 0.655) 0.96 ( ; 0.094) 0.96 ( ; 0.112)

Antiretroviral Exposure and Risk of Osteoporotic Fractures: MV Model 1: Controlling for CKD, age, race, tobacco use, diabetes and BMI; MV Model 2: Controlling for Model 1 variables + concomitant exposure to other ARVs. Hazard Ratio

What Happened in the HAART Era? Higher % of patients on ARVs, low viremia. Increased survival (and time at risk) and increased fracture rates Pre-HAART Era: 1.61 Events/1000 PY HAART Era: 4.09 Events/1000 PY

Antiretroviral Exposure and Risk of Osteoporotic Fractures: HAART Era MV Model 1: Controlling for CKD, age, race, tobacco use, diabetes and BMI; MV Model 2: Controlling for Model 1 variables + concomitant exposure to other ARVs. Drug or Drug Category PY of Exposure Hazard Ratio per Year of Exposure (95% Confidence Interval; p value) Univariate AnalysisMulti-variable Model 1Multi-variable Model 2 Tenofovir (TDF)38, ( ; <0.0001) 1.13 ( ; 0.001) 1.12 ( ; 0.011) Abacavir (ABC)18, ( ; 0.842) 0.96 ( ; 0.313) 0.95 ( ; 0.194) AZT or D4T68, ( ; 0.489) 0.98 ( ; 0.289) 0.99 ( ; 0.600) boosted PI (rPI) 32, ( ; 0.001) 1.08 ( ; 0.026) 1.05 ( ; 0.237) NNRTI48, ( ; 0.771) 0.98 ( ; 0.409) 0.98 ( ; 0.386)

Antiretroviral Exposure and Risk of Osteoporotic Fractures: HAART Era MV Model 1: Controlling for CKD, age, race, tobacco use, diabetes and BMI; MV Model 2: Controlling for Model 1 variables + concomitant exposure to other ARVs. Hazard Ratio

Interaction Between TDF and PI Exposure for OF Risk: HAART Era Concomitant exposure to both TDF and rPI associated with a greater OF risk than exposure to either TDF without rPI or rPI without TDF Hazard Ratio

Exposure to Specific Protease Inhibitors and OF Risk: HAART Era MV Model 1: Controlling for CKD, age, race, tobacco use, diabetes and BMI; MV Model 2: Controlling for Model 1 variables + concomitant exposure to other ARVs. Drug PY of Exposure Hazard Ratio per Year of Exposure (95% Confidence Interval; p value) Univariate AnalysisMulti-variable Model 1Multi-variable Model 2 IDV12, ( ; 0.947)0.98 ( ; 0.579)0.99 ( ; 0.755) ATV12, ( ; 0.097)1.08 ( ; 0.233)1.03 ( ; 0.713) NFV14, ( ; 0.977)0.98 ( ; 0.509)0.98 ( ; 0.512) LPV/RTV15, ( ; <0.0001) 1.13 ( ; 0.005)1.09 ( ; 0.051)

Exposure to Specific Protease Inhibitors and OF Risk: HAART Era MV Model 1: Controlling for CKD, age, race, tobacco use, diabetes and BMI; MV Model 2: Controlling for Model 1 variables + concomitant exposure to other ARVs. Drug PY of Exposure Hazard Ratio per Year of Exposure (95% Confidence Interval; p value) Univariate AnalysisMulti-variable Model 1Multi-variable Model 2 IDV12, ( ; 0.947)0.98 ( ; 0.579)0.99 ( ; 0.755) ATV12, ( ; 0.097)1.08 ( ; 0.233)1.03 ( ; 0.713) NFV14, ( ; 0.977)0.98 ( ; 0.509)0.98 ( ; 0.512) LPV/RTV15, ( ; <0.0001) 1.13 ( ; 0.005)1.09 ( ; 0.051) RTV18, ( ; 0.2)1.04 ( ; 0.349)1.01 ( ; 0.79) ATV/RTV ( ; 0.18)1.08 ( ; 0.378)0.99 ( ; 0.946)

Exposure to Specific Protease Inhibitors and OF Risk: HAART Era MV Model 1: Controlling for CKD, age, race, tobacco use, diabetes and BMI; MV Model 2: Controlling for Model 1 variables + concomitant exposure to other ARVs. Hazard Ratio

Discussion – Entire Study Period Overall, antiretroviral exposure is associated with a non- significant OF risk after controlling for OF risk factors. –HR for cumulative ART exposure is modest compared to other fracture risk factors: White race, advancing age and smoking Cumulative exposure to TDF and boosted PI are each associated with modest increase in fracture risk in univariate analysis, but not after controlling for fracture risk factors. Significant increase in fracture rates in the HAART era –Cumulative ART exposure likely does not account for the increased risk in the HAART era

Discussion – HAART Era - I Fracture risk associated with cumulative exposure to TDF remains significant after controlling for other OF risk factors and concomitant ARV used. Cumulative exposure to boosted PI is also associated with increased OF risk after controlling for other OF risk factors, but not after controlling for concomitant ARVs. –There was an interaction between TDF and boosted PI use. Greater fracture rates, higher (significant) HR for TDF and rPI in the HAART era could be due to longer survival, and exclusion of most patients with no Rx, mono-dual Rx

Discussion – HAART Era - II Among PIs, LPV/RTV is associated with an increased OF risk. Exposure to ATV, NFV or IDV were not associated with increased OF risk. –While these could be explained by concomitant use of RTV with LPV, neither RTV alone nor boosted ATV or IDV were associated with increased risk.

Strengths and Limitations Large sample size (more than 56,000 patients; more than 900 with fracture events) Uniform data collection on exposures and outcomes across VA system, including pre-HAART and HAART eras. Our study is a retrospective cohort study. Osteoporotic fracture events not ascertained (only ICD-9 code used – validated in other VA studies) Bone mineral density is not evaluated. Fractures cannot be proven to be osteoporotic in nature.

Acknowledgements Study funded by VA MERIT grant I01 CX A1 Thanks to the VA Center for Quality Management for access to CCR data and material support Thanks to IAS for giving us the opportunity to share our work