Echocardiography in newly diagnosed atrial fibrillation patients: a systematic review and economic evaluation

Simpson, E., Stevenson, M., Scope, A., Poku, E., Minton, J. and Evans, P. (2013) Echocardiography in newly diagnosed atrial fibrillation patients: a systematic review and economic evaluation. Health Technology Assessment, 17(36), pp. 1-264. (doi:10.3310/hta17360)

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Abstract

Objective To investigate the clinical effectiveness and cost-effectiveness of transthoracic echocardiography (TTE) in all patients who are newly diagnosed with atrial fibrillation (AF).

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Design Narrative synthesis reviews were conducted on the prognostic and diagnostic accuracy of TTE for, and prevalence of, pathologies in patients with AF. Databases were searched from inception. MEDLINE searches were conducted from March to August 2010, and reference lists of articles checked. There were 44 diagnostic accuracy studies, five prognostic studies, and 16 prevalence studies accepted into the review. Given the complexity of the many pathologies identified by TTE, the variety of potential changes to clinical management, and paucity of data, the model focused on changes to oral anticoagulation (OAC). The mathematical model assessed the cost-effectiveness of TTE for patients with AF who were not routinely given OAC, assuming, if left atrial abnormality was detected, that the higher risk of stroke warranted OAC; this meant that patients with a CHADS2 (cardiac failure, hypertension, age, diabetes, stroke doubled) score of 0 [dabigatran etexilate (Pradaxa(®), Boehringer Ingelheim)/rivaroxaban (Xarelto(®), Bayer Schering)] or 0/1 (warfarin) were included. A simplified approach evaluated the additional quality-adjusted life-years (QALYs) required in order for TTE to be perceived as cost-effective at a threshold of £20,000 per QALY.

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Setting Transthoracic echocardiography is usually performed in cardiology clinics but may be used in primary or non-specialist secondary care.

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Participants Patients with newly diagnosed AF. Intervention Transthoracic echocardiography. Main outcome measures Prognosis, diagnostic sensitivity or specificity of TTE, prevalence of pathologies in patients with AF, cost-effectiveness and QALYs.

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Results Prognostic studies indicated that TTE-diagnosed left ventricular dysfunction, increased left atrial diameter and valvular abnormality were significantly associated with an increased risk of stroke, mortality or thromboembolism. There was a high prevalence (around 25-30%) of ischaemic heart disease, valvular heart disease and heart failure in patients with AF. Diagnostic accuracy of TTE was high, with most pathologies having specificity of 0.8 and sensitivity of 0.6. The mathematical model predicted that when the CHADS2 tool is used the addition of TTE in identifying patients with left atrial abnormality appears to be cost-effective for informing some OAC decisions. In the simplified approach a threshold of 0.0033 was required for a TTE to be cost-effective.

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Conclusions When CHADS2 was used, the addition of TTE in identifying patients with left atrial abnormality was cost-effective for informing some OAC decisions. A simple analysis indicates that the number of QALYs required for TTE to be cost-effective is small, and that if benefits beyond those associated with a reduction in stroke are believed probable then TTE is likely to be cost-effective in all scenarios. Our findings suggest that further research would be useful, following up newly diagnosed patients with AF who have undergone TTE, to study treatments given as a result of TTE diagnoses and subsequent cardiovascular events. This could identify additional benefits of routine testing, beyond stroke prevention. Studies assessing the proportion of people with a CHADS2 score of 0 or 1 that have left atrial abnormality would provide better estimates of the cost-effectiveness of TTE, and allow more accurate estimates of the sensitivity and specificity of TTE for identifying left atrial abnormality in AF to be obtained.

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Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Minton, Dr Jonathan
Authors: Simpson, E., Stevenson, M., Scope, A., Poku, E., Minton, J., and Evans, P.
Subjects:R Medicine > R Medicine (General)
College/School:College of Social Sciences > School of Social and Political Sciences > Urban Studies
Journal Name:Health Technology Assessment
Publisher:NIHR Health Technology Assessment Programme
ISSN:1366-5278
ISSN (Online):2046-4924

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