Background: The relationship between lopinavir plasma concentration and the magnitude of lipid elevation after initiation of lopinavir/ritonavir-containing antiretroviral therapy is unclear. The aim of this study was to determine the relationship between drug concentration and lipid changes in two patient cohorts.
Methods: First, we analysed, in an outpatient cohort, the correlation between percentage lipid changes and lopinavir concentration, measured at least 2 weeks or more after initiation of lopinavir/ritonavir. Second, we analysed the correlation between lipid changes and lopinavir and ritonavir plasma concentrations in antiretroviral-naive patients enrolled in a trial comparing nevirapine plus lopinavir/ritonavir (533/133 mg twice daily) with zidovudine/lamivudine plus lopinavir/ritonavir (400/100 mg twice daily).
Results: In 82 outpatients with 215 lopinavir plasma measurements, we found no significant correlations between lopinavir concentration and changes in lipids a median of 522 days after lopinavir/ritonavir initiation in univariable regression analyses, nor in multivariable analyses adjusting for potential confounders. In 40 trial samples collected 24 months after treatment initiation, the mean (95% CI) percentage increase in low-density lipoprotein cholesterol (LDLc) was significantly greater in the nevirapine/lopinavir/ritonavir group (29.4% [16.8-43.3]) than in the zidovudine/lamivudine/lopinavir/ritonavir group (6.8% [-7.3-23.1]; P=0.03). However, the percentage LDLc change did not correlate with lopinavir or ritonavir concentration ratios (r=-0.25; P=0.17 and r=-0.06; P=0.75). Adding lopinavir or ritonavir concentrations into the multivariable regression analyses did not change the relation between LDLc change and randomized treatment.
Conclusions: Neither in an HIV outpatient clinic cohort nor in a trial comparing two lopinavir/ritonavir-containing therapies did we find any relation between changes in lipids, and lopinavir and ritonavir concentration, after initiating lopinavir/ritonavir-containing treatment.