Cost-effectiveness analysis of lopinavir/ritonavir and atazanavir+ritonavir regimens in the CASTLE study.
BACKGROUND
The purpose of the study was to conduct a cost-effectiveness analysis and budget impact analysis comparing lopinavir with ritonavir (LPV/r) and atazanavir plus ritonavir (ATV+RTV) for antiretroviral-naïve patients with a baseline CD4+ T-cell distribution and total cholesterol (TC) profile as reported in the CASTLE study.


METHODS
This decision analysis study used a previously published Markov model of HIV disease, incorporating coronary heart disease (CHD) events to compare the short- and long-term budget impacts and CHD consequences expected for the two regimens.


RESULTS
Patients were assumed to have a baseline CHD risk of 4.6% (based on demographic data) and it was also assumed that 50% of the population in the CASTLE study were smokers. The CHD risk differences (based on percent of patients with TC >240 mg/dL) in favor of ATV+RTV resulted in an average improvement in life expectancy of 0.031 quality-adjusted life years (QALYs) (11 days), and an incremental cost-effectiveness ratio of $1,409,734/QALY. Use of the LPV/r regimen saved $24,518 and $36,651 at 5 and 10 years, respectively, with lifetime cost savings estimated at $38,490. A sensitivity analysis using a cohort of all smokers on antihypertensive medication estimated an average improvement in life expectancy of 31 quality-adjusted days in favor of ATV+RTV, and a cost-effectiveness ratio of $520,861/QALY: a ratio that is still above the acceptable limit within the US.


CONCLUSIONS
The use of an LPV/r-based regimen in antiretroviral-naïve patients with a baseline CHD risk similar to patients in the CASTLE study appears to be a more cost-effective use of resources compared with an ATV+RTV-based regimen. The very small added CHD risk predicted by LPV/r treatment is more than offset by the substantial short- and long-term cost savings expected with the use of LPV/r in antiretroviral-naïve individuals with average to moderately elevated CHD risk.
Simpson
Kit N
KN
Medical University of South Carolina, 151 B Rutledge Avenue, Room 409, Charleston, South Carolina 29425, USA. simpsonk@musc.edu
Rajagopalan
Rukmini
R
Dietz
Birgitta
B
D019380:Anti-HIV Agents / Q000191:economics / Q000627:therapeutic use; D000069446:Atazanavir Sulfate; D002017:Budgets; D018791:CD4 Lymphocyte Count; D003327:Coronary Disease / Q000150:complications / Q000191:economics / Q000453:epidemiology; D017046:Cost Savings; D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D016527:Drug Costs / Q000706:statistics & numerical data; D004359:Drug Therapy, Combination; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy* / Q000191:economics / Q000453:epidemiology; D006801:Humans; D008017:Life Expectancy; D061466:Lopinavir; D008390:Markov Chains; D017059:Models, Econometric; D009842:Oligopeptides / Q000191:economics / Q000627:therapeutic use; D011725:Pyridines / Q000191:economics / Q000627:therapeutic use; D011744:Pyrimidinones / Q000191:economics / Q000627:therapeutic use; D019057:Quality-Adjusted Life Years; D019438:Ritonavir / Q000191:economics / Q000627:therapeutic use; D012907:Smoking / Q000009:adverse effects / Q000191:economics; D014481:United States / Q000453:epidemiology
D019380:Anti-HIV Agents; D009842:Oligopeptides; D011725:Pyridines; D011744:Pyrimidinones; D061466:Lopinavir; D000069446:Atazanavir Sulfate; D019438:Ritonavir