Low rates of first line HAART failure in a resource-limited country (RLC) associated to age, gender, baseline conditions and third drug. Results from the Chilean AIDS Cohort (ChiAC)
C. Beltran1, P. Zitko2, P. Gambra2, M. Contreras3, E. Pereira3, A. Afani4, M. Wolff4, W. Acevedo4, Chilean AIDS Cohort Study Group
1Barros Luco, Infectious Diseases, Santiago, Chile, 2Hospital Barros Luco, Santiago, Chile, 3Universidad de Chile, Inmunología, Santiago, Chile, 4Universidad de Chile, Santiago, Chile
Background: Rates of first HAART virological suppression are increasing to near 80%. DHHS guidelines outline risk factors for failure in developed countries. First regimen failure remains an important problem, especially in RLC where viral load (VL) and resistance testing are often unavailable. Aims of this study are to determine the rate and risk factors for first failure in a RLC, as compared to those reported in developed countries.
Methods: 5,102/ 7,007 patients on treatment nationwide initiated first HAART during prospective follow up by the ChiAC. Failure defined as at least 2 consecutive VL > 80 copies/ml with no further undetectability on same HAART. Age, CD4, clinical diagnosis and VL at baseline, gender and third drug analyzed for association to failure through unadjusted and adjusted univariate analysis, and multivariate analysis; determining OR and CI95 for each variable. Sensitivity analysis performed using different failure cut points (80, 400, 1,000 copies/ml).
Results: 3,439/ 5,102 patients on first HAART had ≥ 2 VL on treatment, being included in the study (21,396 VL tests); 2,820 (80.0%) achieved viral suppression, 619 (20.0%) met failure criteria, 26.2% of them with low level VL (< 1,000 copies/ml). Significant risk factors for failure in multivariate analysis: female (OR 1.35 CI 1.03-1.73), age (OR 0.97 CI 0.96-0.98 p/year old), VL (OR 1.01 CI 1.00-1.01 p/100,000 copies/ml), third drug (OR 3.87 for 3 NRTI, 2.98 for PI, 1.85 for nevirapine); B and C CDC stage significant only for secondary failure (OR 1.72 and 1.67). Except for gender, all factors were consistent for different cut points. Baseline CD4 not associated to failure.
Conclusions: In this RLC population-based study, we found a very high rate of first HAART virological success. Female gender, younger age, high VL and B-C stage at baseline, and third drug different from efavirenz were all significantly associated to failure.
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