Assessment of adherence to triple antiretroviral treatment including indinavir: role of the determination of plasma levels of indinavir.
OBJECTIVE
To assess the contribution of the determination of concentrations of indinavir (IND) in plasma to the assessment of self-reported adherence and keeping of appointments to withdraw drugs from the hospital pharmacy.


METHODS
Adherence was assessed using three criteria: questionnaires, punctuality at appointments to withdraw drugs, and plasma concentrations of IND. Blood samples were obtained from 106 HIV-infected patients who had been receiving IND in combination with two nucleoside reverse transcriptase inhibitors for longer than 6 months. Logistic regression analysis was carried out, and receiver operating characteristic curves were drawn.


RESULTS
The kappa index showed a low concordance for the three measures. When pharmacy appointments and self-report are used together, the nondetection of drug levels is more reliably predicted (AUC = 0.75). With the viral load as the gold standard, plasma levels contribute nothing to the information given by the other two measures combined (AUC = 0.63, AUC = 0.64).


CONCLUSIONS
Measurement of adherence to highly active antiretroviral therapy is complex. Because there is no gold standard for it, we demonstrated that each of three common adherence measures has shortcomings that can be minimized in a combined measurement system. Indinavir plasma levels appear to provide no additional information, so further studies are undoubtedly necessary.
Alcoba
Manuel
M
Leon Hospital, 24071 Leon, Spain.
Cuevas
Maria J
MJ
Perez-Simon
Maria-Rosario
MR
Mostaza
Jose-Luis
JL
Ortega
Luis
L
Ortiz de Urbina
Juan
J
Carro
Jose A
JA
Raya
Carmen
C
Abad
Miriam
M
Martin
Vicente
V
D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy*; D017320:HIV Protease Inhibitors / Q000627:therapeutic use; D006801:Humans; D019469:Indinavir / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D010349:Patient Compliance / Q000706:statistics & numerical data*; D010604:Pharmacy; D012372:ROC Curve; D011795:Surveys and Questionnaires
D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D019469:Indinavir