Adherence over 48 weeks in an antiretroviral clinical trial: variable within patients, affected by toxicities and independently predictive of virological response.
OBJECTIVE
To investigate adherence to antiretroviral therapy over 48 weeks, to investigate the association between adherence and treatment-related symptoms and to investigate the impact of adherence on virological response over 48 weeks among established predictors of treatment success.


METHODS
One-hundred-and-sixty HIV-1 infected protease inhibitor- and stavudine-naive patients participating in a trial of ritonavir/saquinavir versus ritonavir/saquinavir/ stavudine completed an adherence questionnaire and a symptom checklist at weeks 12, 24, 36 and 48. We calculated odds ratios between experienced symptoms and non-adherence. Regression models were used to determine predictors of HIV-1 RNA below 400 copies/ml at week 48, and of the area about the change from baseline over 48weeks (ACFB) in serum HIV-1 RNA.


RESULTS
The percentage of patients reporting missing medication, deviation from time schedule, and dietary prescriptions at separate time-points ranged from 12 to 15%, 32 to 35% and 17 to 22%, respectively. The percentage that changed their level of adherence during 48 weeks ranged from 29% for skipping medication to 48% for deviation from time-schedule. Experienced side-effects were associated with an increased likelihood of non-adherence. Not skipping medication was an independent predictor of both having a serum HIV-1 RNA below 400 copies/ml at week 48 and the ACFB over 48weeks in serum HIV-1 RNA.


CONCLUSIONS
Adherence was an independent predictor of virological response over 48 weeks. The level of adherence is variable within patients over time. This suggests the need for continued adherence monitoring in all patients as part of standard medical practice.
Nieuwkerk
P
P
Department of Medical Psychology, Academic Medical Center, University of Amsterdam, The Netherlands. p.t.nieuwkerk@amc.uva.nl
Gisolf
E
E
Sprangers
M
M
Danner
S
S
D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000821:virology; D017320:HIV Protease Inhibitors / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood / Q000627:therapeutic use; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D016017:Odds Ratio; D010349:Patient Compliance / Q000706:statistics & numerical data*; D011237:Predictive Value of Tests; D012367:RNA, Viral / Q000097:blood; D012044:Regression Analysis; D019438:Ritonavir / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D019258:Saquinavir / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D018119:Stavudine / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D013997:Time Factors; D019562:Viral Load
D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D012367:RNA, Viral; D018119:Stavudine; D019258:Saquinavir; D019438:Ritonavir