Assessment of adherence to HIV protease inhibitors: comparison and combination of various methods, including MEMS (electronic monitoring), patient and nurse report, and therapeutic drug monitoring.
BACKGROUND
Adherence to protease inhibitor-containing antiretroviral therapy is crucial, but difficult to measure.


OBJECTIVE
To compare and combine various methods of measuring adherence to the strict protease inhibitor-containing regimens.


METHODS
The following methods were used: medication event monitoring system (MEMS) caps (electronic monitoring), therapeutic drug monitoring, pill count, pharmacy refill data, questionnaires, diaries (for registration of food patterns and special events related to the use of MEMS), adherence assessment by the physician and clinical nurse specialist, and in-depth interviews. In addition, ultrasensitive viral load and resistance testing was performed.


RESULTS
Twenty-eight patients were included; data could be evaluated in 26. According to MEMS data, 25% of the patients took fewer than 95% of all doses, and two thirds of the patients took fewer than 95% of the doses on time. Only 43% of the patients showed good adherence with food restrictions. Methods that showed significant correlations with MEMS results were patients' self-reported adherence; therapeutic drug monitoring, indicating plasma levels outside predefined ranges; and estimation of adherence by a clinical nurse specialist, especially by in-depth interview.


CONCLUSIONS
Diary-corrected MEMS data gave a detailed insight into patients' adherence patterns. Patients' self-report and therapeutic drug monitoring were significantly correlated with the MEMS data, and the clinical nurse specialist may also play a role in identifying patients who are imperfectly adherent.
Department of Clinical Pharmacy, University Medical Centre Nijmegen, The Netherlands. p.hugen@klinfarm.azn.nl
Patricia W H
PW
Hugen
Nienke
N
Langebeek
David M
DM
Burger
Bert
B
Zomer
Rob
R
van Leusen
Rob
R
Schuurman
Peter P
PP
Koopmans
Yechiel A
YA
Hekster
D016903:Drug Monitoring; D024882:Drug Resistance, Viral; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D017320:HIV Protease Inhibitors / Q000627:therapeutic use*; D006801:Humans; D010349:Patient Compliance; D019562:Viral Load
D017320:HIV Protease Inhibitors