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Limited added value of laboratory monitoring in thiopurine maintenance monotherapy in inflammatory bowel disease patients
Author(s) -
Kreijne Joany E.,
Vries Annemarie C.,
Veer Rozanne C.,
Bouma Gerd,
Dijkstra Gerard,
Voskuil Michiel D.,
West Rachel,
Moorsel Sofia A. W.,
Jong Dirk J.,
Boer Nanne K.,
Woude C. Janneke
Publication year - 2020
Publication title -
alimentary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.308
H-Index - 177
eISSN - 1365-2036
pISSN - 0269-2813
DOI - 10.1111/apt.15734
Subject(s) - medicine , thiopurine methyltransferase , azathioprine , gastroenterology , toxicity , incidence (geometry) , inflammatory bowel disease , maintenance therapy , surgery , chemotherapy , disease , physics , optics
Summary Background To timely detect myelotoxicity and hepatotoxicity, laboratory monitoring at 3‐month intervals is advised throughout thiopurine maintenance treatment for IBD. However, reported incidence rates of myelotoxicity and hepatotoxicity in maintenance treatment are low. Aim To assess incidence rates and clinical consequences of myelotoxicity and hepatotoxicity in thiopurine maintenance therapy after at least 1 year of thiopurine treatment. Methods Retrospective analysis of therapy adjustment for laboratory toxicity in adult IBD patients after 12 consecutive months of azathioprine (AZA) or mercaptopurine monotherapy (ie baseline) between 2000 and 2016. Incidence rates of laboratory toxicity (ie myelotoxicity [leucocyte count <4.0 × 10e9/L, and/or platelet count <150 × 10e9/L] and/or hepatotoxicity (gamma‐glutamyltransferase [GGT], alkaline phosphatase [AP], ALT and/or AST above ULN, excluding isolated increased AST/AP]) and associated diagnostic procedures and complications were assessed. Results In total, 12,391 laboratory assessments were performed on 1132 patients (56% female, AZA 74%) during 3.3 years of median follow‐up. Median monitoring frequency was 3.1 assessments/treatment year. Only 83/12,391 (0.7%) assessments resulted in therapy adjustment, dose reduction in 46 patients, cessation in 28 and allopurinol initiation in nine; risk of therapy adjustment was 1.9% per treatment year. Incidence rates of myelotoxicity were 7.1% (5.1% mild/1.8% moderate/0.1% severe) and hepatotoxicity 5.1% (3.8% mild/1.1% moderate/0.2% severe) per treatment year. Treatment‐related complications with concurrent laboratory toxicity occurred in 12 patients (1.1%) and would not have been prevented by monitoring. Conclusion Severe laboratory toxicity is uncommon after 1 year of thiopurine monotherapy at 4‐month monitoring intervals. Therapy adjustments are rare after detection of laboratory toxicity. After 1 year of thiopurine monotherapy, laboratory monitoring may be lowered to less than a 4‐month interval.