Model for simulation of HIV/AIDS and cost-effectiveness of preventing non-tuberculous mycobacterial (MAC)-disease

Because most HIV-infected patients die of diseases caused by opportunistic pathogens, the prevention of these infections is an important clinical issue. Cost-containment in the healthcare system is a subject of high priority in public debate. Methods to determine cost-effectiveness of different therapeutic strategies are therefore needed to obtain valid data as the basis for decisions on cost reduction without a decrease in the quality of care. A disease state transition model based on a Markov process was developed to simulate the natural history of HIV infection and the acquired immunodeficiency syndrome (AIDS). Using this model survival time and treatment costs for every patient can be estimated and the results of alternative medications compared. We determined the cost-effectiveness (per life-year saved, LYS) of different strategies for prevention of Mycobacterium avium complex infections in AIDS patients whose treatment regimens include protease inhibitors. The cost-effectiveness ratios for treatment strategies vary from 13,510 euro to 46,152 euro per LYS without protease inhibitors and from 22,309 euro to 51,336 euro with protease inhibitors. When azithromycin, clarithromycin, and rifabutin were compared, azithromycin was the most cost-effective medication for preventing M. avium complex. The results were stable against a wide range of parameter variations concerning costs and incidence rates.