ESTIMATING LIFETIME HIV TREATMENT COSTS IN THE UNITED STATES: EARLY VERSUS LATE ENTRY INTO CARE

Purpose: Human immunodeficiency virus (HIV) lifetime treatment costs depend upon the disease stage at which HIV-infected persons are diagnosed, enter care, and start an antiretroviral therapy (ART) regimen. Clinical literature indicates that early ART initiation results in substantial benefits for the health of HIV-infected persons and reduced transmissions. We update estimates of lifetime HIV treatment costs in the U.S. with recent health care utilization and ART costs, and we analyze the effect of early versus late entry into care and treatment on these costs and quality of life variables.

Method: We used the Progression and Transmission of HIV/AIDS (PATH) model to estimate discounted (3%) lifetime treatment costs, quality-adjusted life years (QALYs), and average life expectancies from time of infection, assumed to be at age 35, for cohorts of 10,000 HIV-infected index patients in four categories of CD4 count (cells/µL) at diagnosis: (I) 501 – 900; (II) 351 – 500; (III) 201 – 350 and (IV) ≤ 200. PATH is a Monte Carlo simulation health state transition model that individually tracks a first-generation of HIV-infected persons and the partners they infect from time of infection to death. We assumed that index patient diagnoses were uniformly distributed across the CD4 count range in each of the categories, that patients entered care at the time of diagnosis, and that all patients remained in care throughout their lives. We estimated costs ($US 2011) under treatment initiation eligibility criteria set at CD4 counts of 350 and 500 cells/µL. We also estimated lifetime transmissions to partners of index patients based on patients’ serostatus awareness and use of ART.

Result: Assuming ART initiation at 350 (500) cells/µL, average  lifetime costs varied from $339,000 ($386,000) for  category (I) index patients to $232,000 ($232,000) for category (IV) patients. Discounted QALYs lost increased from 4.92 to 7.58 (4.30 to 7.53) across these categories, while average life expectancy from time of infection decreased from 36.27 to 30.86 (37.76 to 30.96) years. Lifetime transmissions across the categories increased from 0.89 to 1.59 (0.80 to 1.58).

Conclusion: HIV-infected patients who enter care early incur greater lifetime costs, improved quality of life, and reduced transmissions compared with patients who enter care late. Early ART initiation combined with early entry into care increases both these costs and the quality of life benefits.