Impact of obesity on antiretroviral pharmacokinetics and immuno-virological response in HIV-infected patients: a case-control study.

Background: Obesity has high prevalence among HIV-infected patients. Increased adipose tissue mass affects the pharmacokinetics of numerous drugs, but few data are available for antiretroviral drugs.

Objectives: In this study we aimed to explore the pharmacokinetics of antiretroviral drugs and the immuno-virological response in obese patients with HIV infection.

Patients and methods: We examined data from 2009 to 2012 in our hospital's database for HIV-1-infected patients who received an antiretroviral drug (abacavir, emtricitabine, lamivudine, tenofovir, efavirenz, etravirine, nevirapine, atazanavir/ritonavir, darunavir/ritonavir, lopinavir/ritonavir or raltegravir). Obese patients were defined as those with BMI ≥30 kg/m 2 and normal-weight patients as those with BMI 19-25 kg/m 2 . Plasma concentrations ( C 12/24 ) were compared for each antiretroviral drug using a Mann-Whitney test. Suboptimal dosing and virological outcome were assessed by logistic regression, adjusting on covariates.

Results: We enrolled 291 obese and 196 normal-weight patients. Among the 12 analysed antiretroviral drugs, tenofovir, efavirenz and lopinavir C 12 values were significantly lower in obese than normal-weight patients: 66 versus 86 ng/mL, 1498 versus 2034 ng/mL and 4595 versus 6420 ng/mL, respectively ( P  <   0.001). Antiretroviral drug C 12/24 values were more frequently below efficacy thresholds for obese than for normal-weight patients after adjustment for other covariates ( P  <   0.001). Although obese patients showed a higher CD4 count than normal-weight patients (510 versus 444 cells/mm 3 , P  <   0.001), the groups did not differ in virological failure rate.

Conclusions: This study highlights the impact of obesity on antiretroviral drug plasma exposure, but identifies no consequence of this suboptimal exposure on the immuno-virological control in this population.