Incremental prognostic value of the exercise electrocardiogram in the initial assessment of patients with suspected angina: cohort study
BMJ 2008; 337 doi: https://doi.org/10.1136/bmj.a2240 (Published 14 November 2008) Cite this as: BMJ 2008;337:a2240- Neha Sekhri, clinical research fellow1,
- Gene S Feder, professor of primary health care4,
- Cornelia Junghans, research fellow in epidemiology3,
- Sandra Eldridge, professor of medical statistics2,
- Athavan Umaipalan, medical student2,
- Rashmi Madhu, medical student2,
- Harry Hemingway, professor of clinical epidemiology3,
- Adam D Timmis, professor of clinical cardiology2
- 1Newham University Hospital, London
- 2Barts and The London Queen Mary’s School of Medicine and Dentistry, London
- 3Department of Epidemiology and Public Health, University College London Medical School, London
- 4Unit of Academic Primary Health Care, University of Bristol
- Correspondence to: A D Timmis, London Chest Hospital, Barts and The London NHS Trust, London E2 9JX adamtimmis{at}mac.com
- Accepted 10 September 2008
Abstract
Objective To determine whether resting and exercise electrocardiograms (ECGs) provide prognostic value that is incremental to that obtained from the clinical history in ambulatory patients with suspected angina attending chest pain clinics.
Design Multicentre cohort study.
Setting Rapid access chest pain clinics of six hospitals in England.
Participants 8176 consecutive patients with suspected angina and no previous diagnosis of coronary artery disease, all of whom had a resting ECG recorded. 4848 patients with a summary exercise ECG result recorded (positive, negative, equivocal for ischaemia) comprised the summary ECG subset of whom 1422 with more detailed exercise ECG data recorded comprised the detailed ECG subset.
Main outcome measure Composite of death due to coronary heart disease or non-fatal acute coronary syndrome during median follow-up of 2.46 years.
Results Receiver operating characteristics curves for the basic clinical assessment model alone and with the results of resting ECGs were superimposed with little difference in the C statistic. With the exercise ECGs the C statistic in the summary ECG subset increased from 0.70 (95% confidence interval 0.68 to 0.73) to 0.74 (0.71 to 0.76) and in the detailed ECG subset from 0.74 (0.70 to 0.79) to 0.78 (0.74 to 0.82). However, risk stratified cumulative probabilities of the primary end point at one year and six years for all three prognostic indices (clinical assessment only; clinical assessment plus resting ECG; clinical assessment plus resting ECG plus exercise ECG) showed only small differences at all time points and at all levels of risk.
Conclusion In ambulatory patients with suspected angina, basic clinical assessment encompasses nearly all the prognostic value of resting ECGs and most of the prognostic value of exercise ECGs. The limited incremental value of these widely applied tests emphasises the need for more effective methods of risk stratification in this group of patients.
Footnotes
Contributors: NS collected and analysed the data and wrote the paper. CJ and SE analysed the data. AU and RM collected the data. HH interpreted the data and wrote the paper. ADT designed the database, interpreted the data, wrote the paper, and is guarantor. All authors participated in the discussion and interpretation of the final results, contributed to the final paper, and approved the final version submitted for publication. The authors had full access to the data and take responsibility for its integrity.
Funding: The study was funded by the National Health Service’s Service Delivery and Organisation research and development programme, to which interim progress reports were submitted. The funding body was not involved in the study design or analysis.
Competing interests: None declared.
Ethical approval: This study was approved by the multiregional ethics committee (/02/04/095). Permission was given by the National Patient Information Advisory Group (www.advisorybodies.doh.gov.uk/piag/) to link anonymised datasets without individual patient consent.
Provenance and peer review: Not commissioned; externally peer reviewed.
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