Abstract PS3/3
Obese HIV-infected Patients Treated with Efavirenz-containing Regimens Are at Risk of Virological Failure: Evidence from COHERE, a Large European Observational Cohort Collaboration Print
C. Marzolini1, on behalf of the Efavirenz and Obesity Project Team of COHERE in EuroCoord
1University Hospital Basel, Basel, Switzerland
Background: The prevalence of obesity is increasing among HIV-infected patients. Whether standard antiretroviral drug (ARV) dosage is adequate in obese HIV-infected individuals remains unresolved. Using data from a large European collaborative study, we assessed the incidence of virological failure in obese patients treated with efavirenz (EFV)-containing regimens compared to non-obese patients.
Methods: All ART-naïve patients starting an EFV-based regimen with data on weight/height and HIV viral load (VL) prior and after treatment initiation were eligible. Cox regression analyses evaluated the association between body mass index (BMI) and a) time to first undetectable VL (≤50 copies/ml) after treatment initiation and, b) time to VL rebound (two consecutive VL>50 copies/ml) after initial suppression over 5-years follow-up. Analyses were stratified by obesity group (group I: BMI=30-34.9 kg/m2; II: 35-39.9; III: >40) and adjusted for demographic, viral and treatment-related factors.
Results: 13431 patients (76.8% male) were included, of whom 12377 (92.2%) had a normal/low BMI, with 548 (4.1%), 100 (0.7%) and 406 (3.0%) in groups I, II and III, respectively. Of the 13431 patients, 11310 (84.2%) attained virological suppression, of whom 3867 (34.2%) subsequently experienced VL rebound. After adjustment, time to undetectable VL was shorter for obese group II (relative hazard (RH) 1.27, 95% confidence interval (CI): 1.02-1.59) compared to those with normal/low BMI but similar for those in obese groups I and III (RH 1.01, 95%CI: 0.91-1.12 and RH 1.04, 95%CI: 0.93-1.18). Time to subsequent VL rebound was also significantly shorter for obese group II (table). Analyses stratified by gender and ethnicity showed that the association with time to VL rebound was predominantly seen in caucasian race and male gender, suggesting gender and ethnicity-related differences in drug exposure and/or obesity-induced immunomodulatory activity.
Conclusions: Severe obesity warrants careful monitoring of HIV infection. Pharmacokinetic studies are required to clearly define ARV dose requirements in obesity.
 Unadjusted Adjusted 
ObesityRH (95% CI)p-valueRH (95% CI)p-value
I0.91 (0.77, 1.08)0.281.04 (0.87, 1.24)0.70
II1.32 (0.96, 1.81)0.091.47 (1.05, 2.05)0.03
III1.19 (1.00, 1.42)0.051.17 (0.93, 1.46)0.18
II/III vs no/low1.22 (1.05, 1.43)0.011.24 (1.03, 1.50)0.03
[Associations between BMI and time to subsequent VL]

Assigned speakers:
Catia Marzolini , University Hospital Basel , Basel , Switzerland

Assigned in sessions:
17.10.2013, 10:30-12:30, Parallel Session, PS3, ART in Distinct Populations, Copper Hall