Modeling the long-term outcomes and costs of HIV antiretroviral therapy using HIV RNA levels: application to a clinical trial.
A model was developed to gain insight into the potential clinical and economic impact of antiretroviral therapy for HIV-infected patients. Observed HIV RNA levels and CD4 cell counts are used in the model to estimate the probability that an individual progresses from asymptomatic infection to the first AIDS-defining illness and death and to estimate the total net cost of care and long-term cost-effectiveness of antiretroviral therapy. The model was applied to patients in a clinical trial (Merck protocol 035) that compared the surrogate marker response to triple therapy with indinavir (IDV; 800 mg every 8 hr) plus zidovudine (ZDV; 200 mg every 8 hr) plus lamivudine (3TC; 150 mg twice a day) to double therapy with ZDV+3TC. The model projected that for an individual without AIDS who received triple therapy the progression to AIDS and death would be delayed more than for a patient who received double therapy with ZDV+3TC if no other treatment options were offered. Because of this delay in disease progression, the total discounted cost over the initial 5-year period was projected to be $5100 lower for patients who received triple therapy compared with double therapy if suppression with triple therapy lasts up to 3 years. If suppression with triple therapy lasts up to 5 years, costs were projected to be higher with the triple combination, but 81% of the cost is offset by lower disease costs as a result of fewer patients progressing to AIDS. Over 20 years, total discounted cost was projected to be higher for the triple-therapy regimen primarily because of a longer estimated survival time. At 20 years, the incremental cost per life-year gained by adding IDV to a ZDV+3TC regimen was estimated at $13,229, which is well within the range of other widely accepted medical interventions.
Cook
J
J
Merck & Co., Inc., Whitehouse Station, New Jersey 08889, USA. john_cook@merck.com
Dasbach
E
E
Coplan
P
P
Markson
L
L
Yin
D
D
Meibohm
A
A
Nguyen
B Y
BY
Chodakewitz
J
J
Mellors
J
J
D019380:Anti-HIV Agents / Q000191:economics / Q000627:therapeutic use; D018791:CD4 Lymphocyte Count; D002986:Clinical Trials as Topic; D003362:Cost-Benefit Analysis; D003365:Costs and Cost Analysis; D015658:HIV Infections / Q000188:drug therapy* / Q000191:economics* / Q000276:immunology / Q000821:virology; D017320:HIV Protease Inhibitors / Q000191:economics / Q000627:therapeutic use; D015497:HIV-1 / Q000235:genetics; D006801:Humans; D019469:Indinavir / Q000191:economics / Q000627:therapeutic use; D019259:Lamivudine / Q000191:economics / Q000627:therapeutic use; D008954:Models, Biological; D018803:Models, Economic; D010043:Outcome and Process Assessment, Health Care; D012367:RNA, Viral / Q000097:blood; D018894:Reverse Transcriptase Inhibitors / Q000191:economics / Q000627:therapeutic use; D013997:Time Factors; D016896:Treatment Outcome; D019562:Viral Load; D015215:Zidovudine / Q000191:economics / Q000627:therapeutic use
D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine; D015215:Zidovudine; D019469:Indinavir