Lifetime costs of AIDS drops below $100,000
New cost model helps ADAP program set budgets
A complex economic model that uses viral load and CD4 counts in measuring effectiveness of new therapies estimates that treating a patient today will cost about $8,000 a year, and that lifetime treatment cost will be about $25,000 less than it was during the era of monotherapy.
"Costs have gone down, mainly because we are not seeing as many people getting down to the end state of disease now as we used to," says Sissi Pham, PharmD, principal pharmacoeconomic scientist at Glaxo Wellcome, which developed the model and presented it at the 37th Interscience Conference on Antimicrobial Agents and Chemotherapy in Toronto.
The model was tested using a hypothetical cohort of 1,000 patients whose CD4 counts were greater than 500, and who received the latest antiretroviral therapy. The test found that even though the cost per year to treat a patient with antiretroviral drugs remained constant, life expectancy increased.
Three scenarios examined
The model looked at three scenarios: no treatment, effective treatment for one year, and effective treatment for two years. The two-year treatment period was the longest the researchers felt comfortable using because no efficacy data on the new treatment exists beyond that period, Pham explained. Without treatment, average life expectancy was estimated at 11.87 years, with a cost of $8,083 per year. Using the one-year- effective-treatment scenario, life expectancy increased to 12.77 years and cost was $8,017 per year. For two years of effective treatment, life expectancy jumped to 13.66 years at a cost of $7,969 per year.
The model, based on unpublished data from the Multicenter AIDS Cohort Study, takes into account various factors, including the development of resistance and opportunistic infection, Pham says. Previous estimates put the lifetime costs of AIDS at $119,000, but were based on data from 1984, when patients were treated with monotherapy and many experienced opportunistic infections. Pham says other models using new treatment data also have lowered lifetime costs to under $100,000.
On a larger scale, the model has been used to help states set their budgets for the Ryan White CARE Act’s AIDS Drug Assistance Programs (ADAPs), which provide drugs for patients without health insurance.
The statistical model was used to predict ADAP expenditures for New York’s program in 1995. The model’s projection came within 5% of the program’s $29.7 million costs for 1995, Pham says. Because of the accuracy of the model, ADAP programs in other states are using the model for budget projections, including Texas, California, Georgia, and Florida.
In addition, the model gave the ADAP Working Group reliable cost projections when it asked Congress for additional funding this year, says Glaxo-Wellcome spokesman Doug Stokke.
The model also suggested that in New York, total medical costs for HIV/AIDS in the state would be less if a comprehensive ADAP program were provided than if no ADAP program were available, Pham says. "They wanted to know what would it cost the health care system if they didn’t have a comprehensive formulary," she explains.
Although the evaluation bolstered arguments for providing a comprehensive ADAP program in New York defined as offering combination antiretroviral therapy, and treatment and prophylaxis for opportunistic infections the outcome may not be the same in other states, especially those that have fewer patients with advanced AIDS than New York does, she notes.
"It is very population-dependent," she explains. "The reason you saw that in New York is because of its patient demographics a lot of patients have lower CD4 counts."
In yet another economic analysis, researchers at Glaxo-Wellcome have estimated the cost of treating opportunistic infection. Their data, presented at the conference and gathered in collaboration with the University of Alabama and the University of North Carolina, are based on updated, validated treatment algorithms.
The average annualized costs for treatment of the most common opportunistic infections are:
Pneumocystis carinii pneumonia
Mycobacterium avium complex
Kaposi’s sarcoma $5,115
Cryptococcal meningitis $18,237
Cytomegalovirus retinitis $102,021
Esophageal candidiasis $3,098
Non-Hodgkin’s lymphoma $26,127
Pulmonary tuberculosis $21,202
Source: Glaxo-Wellcome, Research Triangle Park, NC, 1997.