Systematic review, meta-analysis and economic modelling of ...

DOI: 10.3310/hta17010 Health Technology Assessment 2013 Vol. 17 No. 1Studies were only included in the diagnostic accuracy review if the index test was measured at orbefore patient arrival at hospital. We excluded prognostic studies that only evaluated troponin (or otherbiomarkers not included in the review, such as CK and CK-MB).For the second diagnostic review, the index test was either CTCA, regardless of sensitivity (e.g. 64 or16 slices) or exercise ECG.Target conditionThe target conditions or outcomes of the reviews of biochemical markers were:• z Diagnostic review Acute MI defined according to the universal definition. 7• z Prognostic review MACE, defined as including at least cardiac death and non-fatal MI (individually oras a composite).The target conditions or outcomes of the review of CTCA and exercise ECG were:• z Diagnostic review CAD identified on ICA.• z Prognostic review MACE, defined as including at least cardiac death and non-fatal MI (individually oras a composite).Reference standardsAcute MI was defined according to the universal definition and required TnI or TnT measurement forat least 80% of the population at least 6 hours after symptom onset. If the reference standard was anybiomarker other than troponin the study was excluded from the diagnostic review. Many studies reportedcomposite diagnostic reference standards or a diagnostic standard of ACS, which included clinicallydiagnosed ACS, development of ECG changes or a subsequent MACE. Where possible we attempted toextract data for MI according to our definition. If this was not possible we made a judgement whether ornot the reference standard approximated to our definition of MI. We included studies that used only newdiagnostic ECG changes or outcome-based MACE (e.g. death, non-fatal MI or life-threatening arrhythmia)alongside a troponin-based reference standard. We excluded studies that used clinically diagnosed ACS(i.e. by history and examination findings alone), undefined or any ECG changes, or process-based MACE(e.g. coronary reperfusion) in the reference standard.Coronary artery disease was determined by ICA and defined in accordance with the primary study.Studies were excluded if coronary angiography was performed only in selected patients, such as thosewith positive CTCA or exercise ECG. The definition of MACEs required that at least 80% of the cohort befollowed for at least 30 days and that a MACE included, at least, cardiac death and non-fatal MI.OutcomesSufficient data were required to construct tables of diagnostic test performance, i.e. numbers of truepositives(TPs), false-negatives (FNs), false-positives (FPs) and true-negatives (TNs). If raw numbers were notreported we attempted to calculate these data from sensitivity and specificity, using prevalence and totalnumber analysed to calculate the denominators. Studies were excluded from analysis as ‘unable to extractdata’ if these calculations were not possible or yielded markedly inconsistent data.Data abstraction strategyData abstraction of each study was performed by one reviewer (CC, MK or JL) into a standardiseddata extraction form and independently checked for accuracy by a second reviewer (CC, MK, JL or SG).Discrepancies were resolved by discussion between the two reviewers and if agreement could not bereached, the principal investigator was consulted (SG). Where multiple publications of the same study wereidentified, data were extracted and reported as a single study. Where there was possible overlap betweencohorts reported from the same author group or study centre we excluded data from one of the cohortsto avoid duplication.© Queen’s Printer and Controller of HMSO 2013. This work was produced by Goodacre et al. under the terms of a commissioning contract issued by the Secretary of Statefor Health. This issue may be freely reproduced for the purposes of private research and study and extracts (or indeed, the full report) may be included in professional journalsprovided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising. Applications for commercial reproduction should beaddressed to: NIHR Journals Library, National Institute for Health Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton SciencePark, Southampton SO16 7NS, UK.11