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  EACS - 12th European AIDS Conference
November 11-14, 2009
Cologne, Germany
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Association of effectiveness and adherence of antiretroviral treatment
  Reported by Jules Levin
EACS Nov 11-14 2009 Cologne Germany
A. Quintana Basterra1, S. Martin Prado1, L. Guisasola Ron1, C. Martinez Martinez1, I. Frago Marquinez2, G. Arroita Gonzalez2 1Txagorritxu Hospital, Pharmacy, Vitoria-Gasteiz, Spain, 2Txagorritxu Hospital, Internal Medicine, Vitoria-Gasteiz, Spain
Objectives: To analyze the association of effectiveness and adherence of antiretroviral treatment and its development in the last four years.
Methods: It was an observational and retrospective study that included patients receiving antiretroviral treatment between January 2005 and December 2008. Patients within four months of antiretroviral therapy were included. Effectiveness was measured with the CD4 cell count and the plasma HIV viral load (copies/mL) that was obtained from de medical history. It was considered HIV viral load undetectable if it was under 50 copies/mL.
The adherence was determined by the computer programme used to dispense antiretroviral therapy monthly. We defined three groups: 1.-patients who picked up > 90% of the dose from the hospital pharmacy, 2.- patients who picked up 80-90% of the dose, 3.-patients who picked up < 80% of the dose. To estimate the adherence it was used as the only indirect method the monthly register of the dispensations.
This table reports in 2005 16.9% of patients had <80% adherence, and the percent of patients with <80% adherence declined to 12.2% in 2006, 8.3% in 2007, and 9.4% in 2008 from Jules: this could be due to more more potent regimens becoming available, more forgiving regimens, that is drugs with better levels and higher genetic barriers to resistance AND/OR it could be due to better adherence by patients who have learned over the years the importance to be more adherent, which could be due to better teaching by clinicians and support staff or they may have learned from prior failures. You can also see CD4 counts increases and undetectable viral load are associated with better adherence


Non-adherence (<80% adherence) appears to improve the most from 16.9% in 2005 to 9.4% in 2008.


The percent of patients achieving undetectable has also increased from 58% in 2005, to 71% in 2006, 74% in 2007, and 82% in 2008.


Percent of patients with undetectable viral load among patients with >90% adherence improved from 67% in 2005 to 87% in 2008, but the main jump occurred from 2005 to 2006 to 83% from 67%. Could this be due to the availability of darunavir, raltegravir and etravirine for patients who had drug resistance? The same improvement in percent undetectable occurred for patients with lower adherence rates of 80-90% and <80%. These data of course also show that <80% adherence results in a serious impairment in achieving undetectable viral load and also suggest 80% adherence as a possible cutoff for serious negative effects of nonadherence.


These data suggest that CD4 recovery appears impaired for patients with <80% adherence.


Conclusions: Adherence is well associated with the value of plasma HIV viral load but not with the CD4 cell count. Not only the adherence but also the effectiveness has improved in the last four years. We consider necessary the pharmaceutical intervention to maintain the level of adherence, because it is the key factor to keep the effectiveness of the antiretroviral therapy.