Correlation between pill counts and biologic effects in an HIV-1 prevention
clinical trial: implications for measuring adherence.
Author(s): Donnell DJ(1), Baeten JM, Hong T, Lingappa JR, Mujugira A, Nakku-Joloba E,
Bangsberg D, Celum C.
Affiliation(s): Author information:
(1)Department of Global Health, University of Washington, Seattle, USA.
deborah@scharp.org
Publication date & source: 2013, AIDS Behav. , 17(2):632-9
Clinic-based pill counts of unused study medication are frequently used to
measure adherence in HIV-1 prevention trials. Monthly pill count adherence data
from the Partners in Prevention HSV/HIV Transmission Study, a double-blind,
placebo controlled trial of twice-daily acyclovir suppression of herpes simplex
virus type 2 (HSV-2) in HIV-1 infected persons was used to compare changes
between 3,381 placebo and active arm participants in two objective biologic
measures of acyclovir's drug activity: reduction in plasma HIV-1 RNA and HSV-2
genital ulcer disease (GUD). Higher acyclovir pill count adherence was associated
with greater reductions in plasma HIV-1 RNA and GUD, indicating pill count data
is strongly correlated with biological effects of adherence. However, when
calculated adherence exceeded 102 % (i.e., fewer pills returned than expected)
and when pill counts were missing because bottles were not returned, plasma HIV-1
RNA and GUD effects were diminished, likely indicating periods of non-adherence.
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