Research proves treatment of OIs to be cost-effective

More evidence of OIs’ impact on AIDS mortality

With the price of prophylaxis for some opportunistic infections (OIs) exceeding $15,000 a year, questions regarding their cost-effectiveness have become increasingly pertinent as many drug-assistance programs face funding shortages. A recent study indicates that prophylaxis against three of the most prevalent OIs is good for the bank as well as the body.

Using a computer-based simulation model, researchers at Boston University and Harvard University Schools of Medicine evaluated a variety of scenarios for preventive therapy, taking into account rates of OI development, survival time, cost of care, and quality of life. The results, published in the Journal of the American Medical Association, were deemed most sensitive to the risk of developing OIs, the impact of OIs on long-term survival, and the cost of prophylaxis.1

Cost can reach $44K annually

The model shows that without prophylaxis, the projected lifetime cost for an AIDS patient averaged $40,228. Providing preventive therapy forpneumocystis cariniipneumonia (PCP) and toxoplasmosis increased lifetime cost to $44,786, mainly due to increased life expectancy it provided. Preventive therapy lifetime costs forMycobacterium aviumcomplex (MAC), cytomega lovirus, or fungus infections ranged from $40,749 to $6,009.

Evaluated in terms of cost-effectiveness in dollars per quality-adjusted life-year (QALY) saved, the analysis determined that PCP and toxoplasmosis preventive therapy with trimethoprim- sulfamethoxazole cost $16,000 per QALY saved. MAC prophylaxis with azithromycin cost $35,000 per QALY saved, and $74,000 with rifabutin. The least cost-effective OI preventive therapy studied was oral ganciclovir for CMV infection, which was estimated at $314,000 per QALY saved.

In an editorial accompanying the article, David Rose, MD, a researcher at Long Island Jewish Medical Center, noted that the results confirm earlier studies showing that PCP prophylaxis was highly cost-effective, while CMV prophylaxis was not cost-effective. The most surprising finding of the study was that MAC prophylaxis regimens are reasonably cost-effective, despite costing up to $2,900 annually.

When combining MAC and PCP prophylaxis, one QALY can be saved for $29,000. To put that cost in perspective, Rose notes that breast cancer treatment yields one year saved for an average of $22,000. The cost rises to $26,000 for coronary artery bypass graft surgery, $6,000 for renal dialysis, and $154,000 for hypercholesterolemia treatment. The costs would be even higher if tied to quality of life, he adds.

The benefit of OI prophylaxis is underscored in a recent study published in AIDS, suggesting that OIs enhance HIV pathogenesis, possibly by causing increased viral load.2

Following 2,081 patients for 30 months, researchers at Johns Hopkins University found that the occurrence of OIs was predictive of increased risk of death, independent of CD4 counts. The exact reasons for this finding are not known, but the authors mention several possibilities. Patients experiencing morbidity from OIs may be forced to interrupt antiretroviral therapy. But another factor recently demonstrated is how OIs appear to upregulate HIV replication and increase viral load, possibly through antigen-mediated activation of latently infected cells, activation of uninfected T cells, or promotion of cytokines.

Pointing out that patients with OIs experience an average monthly loss of CD4 cells double that of patients without OIs during a follow-up interval, the authors suggest that CD4 cell declines may occur at the same time or even after an OI, possibly as a result of increased viral load.

References

1. Freedberg K, Sharfstein J, Seage G, et al. The cost effectiveness of preventing AIDS-related opportunistic infections. JAMA 1998; 279:130-136.

2. Chaisson R, Gallant J, Keruly J, et al. Impact of opportunistic disease on survival in patients with HIV infection. AIDS 1998;12:29-33.