This presentation is part of: Poster Session - CEA: Methods and Applications; Health Services Research
POTENTIAL COST EFFECTIVENESS OF AGGRESSIVELY TREATING MULTI-DRUG-EXPERIENCED HIV-POSITIVE PATIENTS
Ahmed M. Bayoumi, MD, MSc, St. Michael's Hospital, University of Toronto, Inner City Health Research Unit, Toronto, ON, Canada, Gillian D. Sanders, PhD, Duke, Medicine, Durham, NC, Julie Munakata, MS, VA Palo Alto Health Care System, Health Economics Resource Center, Menlo Park, CA, and Douglas K. Owens, MD, MS, VA Palo Alto Health Care System, AIDS Research Center, Palo Alto, CA.
The optimal management of multi-drug experienced HIV infected patients is unknown. We evaluated the potential cost effectiveness of aggressive treatment for this group with multiple antiretroviral drugs or novel therapies that are expensive or toxic. This approach may enhance the probability of achieving virologic suppression but could increase costs and decrease quality of life. We developed a Markov analysis model of HIV infection to evaluate standard and aggressive therapy. The model follows individuals from the time antiretroviral therapy is initiated until death. The base case had a viral load of 40,000 copies/mL and a CD4 count of 350 cells/mm3. We assumed that individuals would change regimens after intolerance, virologic rebound, or clinical disease progression and used third line regimen. We modeled standard therapy as a 4-drug fourth line regimen and aggressive therapy as fourth line regimen a combination of at least 4 drugs but with increased costs. Patients intolerant of aggressive therapy would step down to standard therapy. Subsequently, patients started therapy which diminishes, but does not suppress, viral load levels. We modeled the effects of aggressive therapy on the enhanced probability (odds ratio) of virologic suppression and incremental costs, with base case values of 3 and $15,000, respectively. In sensitivity analyses, we increased the risk of drug-limiting intolerance to 50%, and decreased quality of life (QOL) by 10% for aggressive therapy. Aggressive therapy was associated with incremental survival of 6.4 months, discounted quality-adjusted survival of 5.3 months, and a cost effectiveness ratio of $75,500 per quality adjusted life year (QALY), if drug tolerance and QOL were similar to standard therapy. The most important determinants of cost effectiveness were the efficacy and cost of aggressive therapy; incremental costs of aggressive therapy would have to be at most $6000, $8000, or $9000 if the odds ratio for viral suppression was 2, 3, or 4 compared to standard therapy at a cost effectiveness threshold of $50,000/QALY. Incorporating intolerance and quality of life effects, the maximal incremental cost was $4000. Our model suggests that aggressive HIV therapy may be cost effective if adverse effects are minimal. Ongoing trials may characterize the clinical parameters necessary for cost effectiveness, but antiretroviral therapy prices may have to fall considerably for routine use of aggressive therapy to be economically attractive.
