Antiretroviral resistance among HIV-infected persons who have died in British Columbia, in the era of modern antiretroviral therapy.

BACKGROUND: The prevalence of antiretroviral resistance among persons enrolled in the centralized HIV/AIDS Drug Treatment Program in British Columbia, Canada, who had died between July 1997 and December 2001, was investigated, to determine the degree to which antiretroviral resistance contributed to mortality.
METHODS: During this period, 637 deaths had occurred. The last plasma sample obtained during therapy was genotyped retrospectively for treated individuals who had died of a nonaccidental cause. Samples with plasma human immunodeficiency virus (HIV) loads <500 copies/mL were not genotyped. Drug resistance among 1220 living HIV-infected persons who had experienced virologic therapy failure during the study period also was examined.
RESULTS: Of 554 individuals who had died of nonaccidental causes, 58 (10.4%) were antiretroviral naive, and 99 (17.9%) had very brief exposure to antiretroviral therapy (median, 2 months). The majority of isolates from the remaining 397 individuals harbored either no major resistance mutations or represented samples with plasma HIV suppression of <500 copies/mL. Resistance to >/=1, >/=2, or 3 drug classes was observed in 76%, 42%, and 11% of individuals, respectively, in the group of 1220 living individuals experiencing virologic therapy failure, compared with only 44%, 23%, and 5% of individuals, respectively, who had died (P<.001).
CONCLUSION: Only a relatively low prevalence of multidrug resistance was observed in this cohort, indicating that the exhaustion of treatment options because of drug resistance was not a significant contributor to mortality.