Table C-5KQ1c: Diagnostic sensitivity and specificity of TPMT determinations – risk of bias assessment of included studies, part 2

StudyTPMT activity test results assessed independent of genotyping resultsGenotyping results assessed independent of TPMT activity test resultsClinical data availability before assessing activity or genotyping was routineReporting of uninterpretable test resultsExplanation provided for study withdrawalsHWE TestedApplicabilitySummary risk of bias assessment
Ansari, 200828UnclearUnclearUnclearNoYesYesApplicableFair - Unclear if TPMT testing was blinded.
Ansari, 200229UnclearUnclearUnclearNoNoNoUnclear - Uncertain representativeness of adult IBD patients presenting to a specialty clinic.
Excluded patients with low TPMT enzymatic activity
Fair - Unclear if TPMT testing was blinded. HWE not tested.
Gardiner, 200830UnclearUnclearUnclearNoYesNoUnclear - Well representative of adult IBD patients presenting to a gastroenterology clinic, but excluded patients with low TPMT enzymatic activityPoor - HWE not tested. Sample not representative. Unclear if phenotyping influenced by genotyping results, and vice versa.
Haglund, 200431UnclearUnclearUnclearNoYesNoUnclear - Uncertain representativeness of adolescent and adult IBD patients. Patients were pre-selected based on their TPMT activity.Poor - HWE not tested. Exclusion criteria not reported. Samples selected based on TPMT activity. TPMT testing not blinded.
Hindorf, 200632UnclearUnclearUnclearNoNoNoUnclear - Not representative of IBD patients, including only those currently or previously on thiopurinesFair - HWE not reported. Unclear if genotyping was blinded.
Hindorf, 200433UnclearUnclearUnclearUnclearYesNoUnclear - Not representative of adult IBD patients, including only adult IBD patients on long-term thiopurine treatmentFair - HWE not reported. Unclear if TPMT testing was blinded.
Langley, 200234YesYesYesUnclearNoNoUnclear - Not representative of AIH patients, including only those in a tertiary care settingPoor - HWE not reported. Unclear representativeness of sample and unclear random genotyping of a subset of patients.
Lindqvist, 200635UnclearUnclearYesUnclearYesNoUnclear - Not representative of adult IBD patients, excluding those likely to experience adverse events.Fair - Sample not representative. Unclear if TPMT testing was blinded.
Marinaki, 200336UnclearUnclearUnclearNoNoNoUnclear - Uncertain representativeness of IBD patients. Includes only those of South Asian ancestry.Fair - Unclear representativeness of sample. Unclear if TPMT testing was blinded.
Okada, 200537UnclearUnclearUnclearNoNoNoUnclear - Not representative of Japanese SLE patients, including only those in a tertiary care setting.Poor - Unclear representativeness of sample. Unclear if TPMT testing was blinded and whether testing was non-selective.
Schwab, 200238UnclearUnclearUnclearNoNoNoUnclear - Not representative of IBD patients, including only those in a tertiary care setting.Fair - Unclear representativeness of sample. Unclear if TPMT testing was blinded.
Snow, 199539UnclearUnclearUnclearNoYesNoUnclear - Uncertain representativeness of autoimmune dermatologic patients. No description of testing methodology.Poor - Poorly reported testing methodology and inclusion criteria.
Stassen, 200940UnclearUnclearUnclearUnclearNoNoUnclear - Little to no reporting of population characteristics.Fair – Unclear if TPMT testing was blinded.
Stocco, 200541UnclearUnclearYesNoYesNoUnclear - Uncertain representativeness of IBD patients.Poor - Unclear representativeness of sample. Unclear if TPMT testing was blinded. Unclear if phenotyping influenced by genotyping results or other factors.
Stocco, 200442UnclearUnclearUnclearNoNoNoUnclear - Not representative of IBD patients, including only those in a tertiary care setting.Poor - Unclear representativeness of sample. Unclear if TPMT testing was blinded.
von Ahsen, 200543UnclearUnclearUnclearUnclearYesNoUnclear - Unrepresentative of active Crohn's disease patients.Fair - Unclear representativeness of sample. Unclear if TPMT testing was blinded.
Winter, 200744UnclearUnclearUnclearYesYesNoUnclear - Uncertain representativeness of patients with IBD. All had previously received thiopurinesFair - Unclear representativeness of sample. Unclear if TPMT testing was blinded.
Newman, 201045UnclearUnclearYesNoYesNoUnclear - Uncertain representativeness of patients with IBD. excluded patients with important adverse events due to previous thiopurine exposureFair - Unclear blinded assessment, and exclusion of participants likely to experience SAE
Hindorf, 201046UnclearUnclearUnclearNoYesNoLittle reporting of patient characteristic s. Unclear representativeness of AIH patientsFair - Unclear blinded assessment

Abbreviations: HWE = Hardy-Weinberg equilibrium; IBD = inflammatory bowel disease; TPMT = thiopurine methyltransferase.

From: Appendix C, Evidence Tables

Cover of Assessment of Thiopurine Methyltransferase Activity in Patients Prescribed Azathioprine or Other Thiopurine-Based Drugs
Assessment of Thiopurine Methyltransferase Activity in Patients Prescribed Azathioprine or Other Thiopurine-Based Drugs.
Evidence Reports/Technology Assessments, No. 196.
Booth RA, Ansari MT, Tricco AC, et al.

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