Adherence to antiretroviral therapy and its impact on clinical outcome in HIV-infected patients.

We analyse data on patient adherence to prescribed regimens and surrogate markers of clinical outcome for 168 human immunodeficiency virus infected patients treated with antiretroviral therapy. Data on patient adherence consisted of dose-timing measurements collected for an average of 12 months per patient via electronic monitoring of bottle opening events. We first discuss how such data can be presented to highlight suboptimal adherence patterns and between-patient differences, before introducing two novel methods by which such data can be statistically modelled. Correlations between adherence and subsequent measures of viral load and CD4+T-cell counts are then evaluated. We show that summary measures of short-term adherence, which incorporate pharmacokinetic and pharmacodynamic data on the monitored regimen, predict suboptimal trends in viral load and CD4+T-cell counts better than measures based on adherence data alone.

Costs of care for HIV infection in a managed care population from 1995 to 1997.

OBJECTIVE: To determine costs of drug and nondrug treatment of HIV-infected patients during introduction of protease inhibitors and combination therapy. STUDY DESIGN: Longitudinal, observational study of insurance claims data. PATIENTS AND METHODS: Data from managed care organizations in Texas and California contracting with an HIV case management group were reviewed for all non-Medicaid/non-MediCal adults infected with HIV for costs of drugs and nondrug treatment per HIV-infected member per month from January 1995 to December 1997. Costs of care for patients with and without undetectable viral loads (< 400 copies/mL) were quantified. RESULTS: Per HIV-infected member, average monthly drug costs increased, nondrug costs decreased, and total costs remained stable. Quarterly mortality rates decreased from 4.8% to 0.25%. From the first quarter of 1996 to the last quarter of 1997, the proportion of patients with undetectable viral loads increased from 6% to 56%. Increasing drug costs and decreasing nondrug costs were observed in patients with and without undetectable viral loads, but costs were higher for the latter: after the second quarter of 1996, drug costs were $67 to $277 higher for patients without undetectable viral loads, nondrug costs were $185 to $741 higher, and total costs were $333 to $808 higher. CONCLUSIONS: Reduced mortality rates and increased viral suppression to undetectable levels were observed during introduction of protease inhibitors and combination therapy in this MCO setting. Increased average monthly drug costs per HIV-infected patient were offset by decreased average monthly nondrug costs, and both costs were lower when patients achieved undetectable viral loads.