Trends in plasma HIV-RNA suppression and antiretroviral resistance in British Columbia, 1997-2010.

OBJECTIVES: To examine temporal trends in plasma viral load (pVL) suppression and antiretroviral resistance from 1997 to 2010 in British Columbia (BC), Canada, and determine characteristics, pVL ranges, and resistance profiles of HIV-positive individuals with unsuppressed pVL in 2010.
METHODS: HIV-positive individuals ≥19 years old in the provincial database at the BC Centre for Excellence in HIV/AIDS were included. Virological suppression was defined as 2 consecutive pVL <500 copies per milliliter within each calendar year. Temporal trends were evaluated using the Cochran-Armitage test. Persons with suppressed vs. unsuppressed pVL in 2010 were compared using the Pearson χ² or Fisher exact test (categorical variables) and the Wilcoxon rank-sum test (quantitative variables), including unsuppressed individuals only if they were on antiretroviral therapy (ART) in 2010 or their baseline CD4 count was <350 cells per cubic millimeter or <500 cells per cubic millimeter, in separate analyses.
RESULTS: The proportion of individuals with suppressed pVL increased from 24% to 80% (P < 0.001). In comparative analyses, individuals with unsuppressed pVL (877 of 6142) were more likely to be female (30% vs. 16%), younger (median, 43 vs. 48 years), have injection drug use history (38% vs. 30%), report Aboriginal ancestry (30% vs. 16%), and have hepatitis C coinfection (57% vs. 34%) (all P < 0.001). Similar patterns were observed using the <500 cells per cubic millimeter CD4 cutoff. The median pVL of all unsuppressed individuals in 2010 was 12,896 copies per milliliter (interquartile range, 1495-47,763).
CONCLUSIONS: The proportion of individuals achieving pVL suppression in BC has increased markedly since 1997; however, further efforts are needed to maximize the individual and societal benefits of modern antiretroviral therapy.