Adherence to thiopurine treatment in out-patients with Crohn's disease.
BACKGROUND
High frequency of incomplete or non-response to azathioprine (AZA) and/or mercaptopurine (MP) limit their use in Crohn's disease (CD). Non-adherence is considered to be of relevance for ineffectiveness.


OBJECTIVE
To assess adherence to thiopurines in CD out-patients treated in a single gastroenterology practice.


METHODS
Patients were eligible for inclusion if they received AZA/MP for at least 3 months. After follow-up of 3 months, adherence to AZA/MP was assessed by quantitation of relevant thiopurine metabolite levels in red blood cells as well as by patients' self-report using standardized questionnaire.


RESULTS
Sixty-five patients were prospectively included. Six patients (9.2%) had metabolite profiles indicative of non-adherence. Self-assessed questionnaire revealed non-adherence in four of 56 patients (7.1%). Therapeutic drug monitoring (TDM) and self-assessment as two independent methods had a concordance rate of 75%. Metabolite levels and self-assessed adherence were not significantly different between patients in remission compared with those with active disease.


CONCLUSIONS
Out-patients with CD treated in a single gastroenterology practice had a satisfactory adherence (>90%) to thiopurine therapy. Different measures of adherence (TDM and self-report) applied to the same patient suggest comparable levels. TDM appears to be a reliable tool to assess adherence to thiopurines in clinical practice.
Bokemeyer
B
B
Gastroenterology Practice Minden, Minden, Germany.
Teml
A
A
Roggel
C
C
Hartmann
P
P
Fischer
C
C
Schaeffeler
E
E
Schwab
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D003424:Crohn Disease / Q000188:drug therapy* / Q000201:enzymology; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008297:Male; D015122:Mercaptopurine / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D008780:Methyltransferases / Q000378:metabolism; D008875:Middle Aged; D010349:Patient Compliance; D011795:Surveys and Questionnaires
D000893:Anti-Inflammatory Agents; D007166:Immunosuppressive Agents; C488629:azathiopurine; D015122:Mercaptopurine; D008780:Methyltransferases; C022745:thiopurine methyltransferase