It is clear that treatment outcomes have dramatically improved since the introduction of effective combination antiretroviral therapy in the mid-1990s, and since then HAART efficacy has improved over time as new and better drugs have been developed. But the factors that contribute to this improved treatment success are not yet fully understood.

To shed further light on this issue, Italian investigators retrospectively analyzed the efficacy of first-line regimens in 1998 and in 2006. Results were presented last week at the 9th International Congress on Drug Therapy in HIV Infection (HIV9) in Glasgow, Scotland.

The analysis included all 146 patients starting first-line HAART at their institutions during these years (67 in 1998; 79 in 2006). About three-quarters were men, the mean age was 38 years, the mean baseline CD4 count was 250 cells/mm3, and baseline viral load was 5.66 log10 copies/mL. The 1998 and 2006 groups had similar baseline values.

Using clinical records, the researchers collected data on patient age, sex, HIV risk factors, co-morbidities, CDC AIDS disease stage, treatment adherence, and any recorded toxicity-related adverse events or treatment modifications. They also looked at baseline, 24-week, and 48-week CD4 cell counts, HIV viral load, and levels of blood glucose, total cholesterol, and triglycerides.

Results

• HIV suppression at 48 weeks was observed in 59.1% of patients in 1998 and 88.6% in 2006 (P < 0.001).

• In a multivariate analysis, virological suppression was independently associated only with:

• 48-week adherence (odds ratio [OR] 20.6; P < 0.001);
• Being treated in 2006 vs 1998 (OR 8.6; P < 0.001).

• Adherence to HAART was significantly associated with better CD4 cell recovery at 24 and 48 weeks (P = 0.01 and 0.02, respectively).

• Demographic factors, baseline immune parameters, and adverse events did not significantly alter the likelihood of achieving virological suppression.

"Our results indicate that after 48 weeks, patients treated with more recent first-line regimens have better chances of viral suppression and immune recovery than at the dawn of HAART," the researchers concluded.

"Adherence to therapy seems to be increased in parallel over time, and to be tightly associated with both outcomes," they added. "The independent association of better outcomes with the year of treatment and not with any other factor, including the incidence of adverse events, would suggest greater intrinsic potency of new HAART regimens."

Ospedale Civile Spirito Santo, Pescara, Italy; Department of Infectious Disease - University of Sassari, Sassari, Italy; Ospedale "Santa Maria della Misericordia", Perugia, Italy; Ospedale "SS. Annunziata" - University of Chieti, Chieti, Italy; Ospedale "L. Sacco", Milano, Italy; Section of Epidemiology and Public Health, University of Chiety, Chieti, Italy.

11/18/08

Reference
F Sozio, V Soddu, G De Socio, and others. Comparison of the efficacy at 48 weeks of first-line antiretroviral treatment for HIV infection in 1998 and 2006: a multicentric investigation. 9th International Congress on Drug Therapy in HIV Infection. Glasgow, Scotland. November 9-13, 2008. Journal of the International AIDS Society 11(Suppl 1):P19. November 10, 2008.