Long-term utility of measuring adherence by self-report compared with pharmacy record in a routine clinic setting.
OBJECTIVE
To compare long-term adherence to antiretroviral therapy in an HIV service, as measured by self-report and by pharmacy records. To determine the level of adherence by each measure required to suppress viral load in a majority of patients.


METHODS
The percentage of prescribed doses taken was calculated from (a) the number of missed doses in the previous 28 days reported by patients in a questionnaire at each clinic visit, and (b) pharmacy dispensing records. These were compared with each other and with HIV viral load data.


RESULTS
Mean adherence was 96.2% by pharmacy record over 44 months and 98.6% by self-report over 25 months. The two methods correlated with each other (P<0.001) and the proportion of patients with viral load <400 HIV-1 RNA copies/mL increased with adherence as measured by self-report (P=0.001) and pharmacy record (P=0.004). Fewer than 60% of patients always had viral loads <400 copies/mL if adherence fell below 95% (pharmacy record) or 97% (self-report). Adherence was higher for once-daily than for twice-daily therapy (by pharmacy record: 97.2% vs. 96.0%; P<0.001). Adherence by both measures increased over time.


CONCLUSIONS
Self-reported antiretroviral adherence correlates with pharmacy dispensing records and predicts suppression of viral load at levels >or=97%. It is practical to adopt this into routine HIV clinical care.
Fairley
C K
CK
Melbourne Sexual Health Centre, University of Melbourne, Melbourne, Victoria, Australia. cfairley@unimelb.edu.au
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D000554:Ambulatory Care Facilities; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D003157:Community Pharmacy Services / Q000706:statistics & numerical data; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D015658:HIV Infections / Q000188:drug therapy* / Q000523:psychology / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D008499:Medical Records; D010349:Patient Compliance / Q000706:statistics & numerical data*; D012367:RNA, Viral / Q000097:blood; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012650:Self Disclosure; D014739:Victoria; D019562:Viral Load
D019380:Anti-HIV Agents; D012367:RNA, Viral