Durability and Predictors of Success of Highly Active Antiretroviral Therapy for Ambulatory HIV-Infected Patients

The benefits of highly active antiretroviral therapy (HAART) in the treatment of HIV infection have been well described, including viral suppression, CD4 lymphocyte repletion and durable reductions in opportunistic infections and death. However, the durability of the effectiveness of HAART remains to be delineated. Factors that limit the success of HAART include poor therapy adherence, therapy complexity, and co-morbid conditions. In this report, the authors describe correlates of HAART efficacy over time among HIV-infected patients in the HIV Outpatient Study (HOPS).

HOPS is a prospective cohort into which patients are continuously recruited. It has included 6,000 patients seen in more than 88,000 visits to 10 HIV clinical care sites in eight US cities that, in aggregate, provide care for about 2,500 HIV-infected patients yearly. Participating physicians have extensive experience treating HIV-infected patients. Information from outpatient visits is abstracted from patient records and entered electronically by trained abstractors.

Categories of information abstracted include demographic factors, risk factors for HIV, symptoms, diseases, medications, and laboratory values. The primary payment source is documented as private insurance, Medicare, Medicaid, self-payment or Ryan White Care Act. Analysis included AIDS-related deaths and disease (opportunistic infection (OI)) rates among patients with CD4 nadir Mortality and OI rates were calculated for 1,769 patients who ever had a CD4 cell count <100 x 10?/L in association with HAART, seen from January 1994 through June 2000. HAART's durability, effect, and patterns of utilization were analyzed using data from 1,022 patients with at least one CD4 cell count Death rates declined from 29.5 deaths/100-person years (PY) in 1995 -- (just prior to HAART widespread use) -- to a rate of 11.5 deaths/100 PY observed by the fourth quarter of 1996 when HAART utilization was widespread. Death rates subsequently remained stably low with a mean quarterly mortality rate of 12.0 deaths/100 PY for the first three quarters of 2000. Since the fourth quarter of 1997, the prevalence of HAART use among patients remained between 82.3 percent and 86.3 percent. Reductions in death and disease were seen regardless of type of HAART received or baseline demographics of age, race, sex, HIV risk category, or source of medical payment. Rates of chemoprophylaxis for PCP and MAC remained stable throughout the period of analysis (about 90 percent and 50 percent, respectively).

Durable treatment success (>12 months) was most likely for pre-HAART treatment naive patients, and durably successful first HAART most often contained one protease inhibitor, particularly indinavir or nelfinavir. Durable success was most likely with first (49 percent) than with second (29.6 percent) or third or more HAART regimens (14.9 percent). Time to success with first HAART was shorter for durable than non-durable responders (3.6 vs. 5.3 months).

After a lengthy discussion of implications and questions raised by the study, the authors stressed their findings as ones that show that sequential HAART regimens were of progressively shorter duration, demonstrated less viral suppression and CD4 cell count benefit, yet low morbidity and mortality rates were sustained. In conclusion, the authors stated that patients clearly derive progressively less benefit from successive and increasingly more complex and more difficult to tolerate HAART regimens.

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