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

Protocol for a multicentre and prospective follow-up cohort study of early detection of atrial fibrillation, silent stroke and cognitive impairment in high-risk primary care patients: the PREFA-TE study

BACKGROUND

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Future estimations suggest an increase in global burden of AF greater than 60% by 2050. Numerous studies provide growing evidence that AF is not only associated with stroke but also with cognitive impairment and dementia.

AIM

The main goal is to assess the impact of the combined use of cardiac rhythm monitoring devices, echocardiography, biomarkers and neuroimaging on the early diagnosis of AF, silent strokes and cognitive decline, in subjects at high risk of AF.

METHODS AND ANALYSIS

Two-year follow-up of a cohort of individuals aged 65-85 years at high risk for AF, with no prior diagnosis of either stroke or dementia. The study involves baseline echocardiography, biomarkers, and neuroimaging, yearly cardiac monitoring, and semiannual clinical assessments. Different parameters from these tests will be analysed as independent variables. Throughout the study period, primary outcomes: new diagnoses of AF, stroke and cognitive impairment, along with any clinical and therapeutic changes, will be registered. A first descriptive and bivariate statistical analysis, appropriate to the types of variables, will be done. The information obtained from the data analysis will encompass adjusted risk estimates along with 95% confidence intervals. Event risk predictions will rely on multivariate Cox proportional hazards regression models. The predictive value of the model will be evaluated through the utilisation of receiver operating characteristic curves for area under the curve calculation. Additionally, time-to-event analysis will be performed using Kaplan-Meier curves.

ETHICS AND DISSEMINATION

This study protocol has been reviewed and approved by the Independent Ethics Committee of the Foundation University Institute for Primary Health Care Research-IDIAP Jordi Gol (expedient file 22/090-P). The authors plan to disseminate the study results to the general public through various scientific events. Publication in open-access journals and presentations at scientific congresses, seminars and meetings is also foreseen.

TRIAL REGISTRATION NUMBER

NCT05772806.

Economic and Health Value of Delaying Atrial Fibrillation Progression Using Radiofrequency Catheter Ablation

BACKGROUND

Radiofrequency catheter ablation (RFCA) is an established treatment for atrial fibrillation (AF) refractory to antiarrhythmic drugs. The economic value of RFCA in delaying disease progression has not been quantified.

METHODS

An individual-level, state-transition health economic model estimated the impact of delayed AF progression using RFCA versus antiarrhythmic drug treatment for a hypothetical sample of patients with paroxysmal AF. The model incorporated the lifetime risk of progression from paroxysmal AF to persistent AF, informed by data from the ATTEST (Atrial Fibrillation Progression Trial). The incremental effect of RFCA on disease progression was modeled over a 5-year duration. Annual crossover rates were also included for patients in the antiarrhythmic drug group to mirror clinical practice. Estimates of discounted costs and quality-adjusted life years asssociated with health care utilization, clinical outcomes, and complications were projected over patients' lifetimes.

RESULTS

From the payer's perspective, RFCA was superior to antiarrhythmic drug treatment with an estimated mean net monetary benefit per patient of $8516 ($148-$16 681), driven by reduced health care utilization, cost, and improved quality-adjusted life years. RFCA reduced mean (95% CI) per-patient costs by $73 (-$2700 to $2200), increased mean quality-adjusted life years by 0.084 (0.0-0.17) and decreased the mean number of cardiovascular-related health care encounters by 24%.

CONCLUSIONS

RFCA is a dominant (less costly and more effective) treatment strategy for patients with AF, especially those with early AF for whom RFCA could delay progression to advanced AF. Increased utilization of RFCA-particularly among patients earlier in their disease progression-may provide clinical and economic benefits.

Cost-effectiveness of catheter ablation versus medical therapy for the treatment of atrial fibrillation in the United Kingdom

Introduction

Research evidence has shown that catheter ablation is a safe and superior treatment for atrial fibrillation (AF) compared to medical therapy, but real‐world practice has been slow to adopt an early interventional approach. This study aims to determine the cost effectiveness of catheter ablation compared to medical therapy from the perspective of the United Kingdom.

Methods

A patient‐level Markov health‐state transition model was used to conduct a cost‐utility analysis. The population included patients previously treated for AF with medical therapy, including those with heart failure (HF), simulated over a lifetime horizon. Data sources included published literature on utilization and cardiovascular event rates in real world patients, a systematic literature review and meta‐analysis of randomized controlled trials for AF recurrence, and publicly available government data/reports on costs.

Results

Catheter ablation resulted in a favorable incremental cost‐effectiveness ratio (ICER) of £8614 per additional quality adjusted life years (QALY) gained when compared to medical therapy. More patients in the medical therapy group failed rhythm control at any point compared to catheter ablation (72% vs. 24%) and at a faster rate (median time to treatment failure: 3.8 vs. 10 years). Additionally, catheter ablation was estimated to be more cost‐effective in patients with AF and HF (ICER = £6438) and remained cost‐effective over all tested time horizons (10, 15, and 20 years), with the ICER ranging from £9047–£15 737 per QALY gained.

Conclusion

Catheter ablation is a cost‐effective treatment for atrial fibrillation, compared to medical therapy, from the perspective of the UK National Health Service.

Smoking cessation medicines and e-cigarettes: a systematic review, network meta-analysis and cost-effectiveness analysis

BACKGROUND

Cigarette smoking is one of the leading causes of early death. Varenicline [Champix (UK), Pfizer Europe MA EEIG, Brussels, Belgium; or Chantix (USA), Pfizer Inc., Mission, KS, USA], bupropion (Zyban; GlaxoSmithKline, Brentford, UK) and nicotine replacement therapy are licensed aids for quitting smoking in the UK. Although not licensed, e-cigarettes may also be used in English smoking cessation services. Concerns have been raised about the safety of these medicines and e-cigarettes.

OBJECTIVES

To determine the clinical effectiveness, safety and cost-effectiveness of smoking cessation medicines and e-cigarettes.

DESIGN

Systematic reviews, network meta-analyses and cost-effectiveness analysis informed by the network meta-analysis results.

SETTING

Primary care practices, hospitals, clinics, universities, workplaces, nursing or residential homes.

PARTICIPANTS

Smokers aged ≥ 18 years of all ethnicities using UK-licensed smoking cessation therapies and/or e-cigarettes.

INTERVENTIONS

Varenicline, bupropion and nicotine replacement therapy as monotherapies and in combination treatments at standard, low or high dose, combination nicotine replacement therapy and e-cigarette monotherapies.

MAIN OUTCOME MEASURES

Effectiveness - continuous or sustained abstinence. Safety - serious adverse events, major adverse cardiovascular events and major adverse neuropsychiatric events.

DATA SOURCES

Ten databases, reference lists of relevant research articles and previous reviews. Searches were performed from inception until 16 March 2017 and updated on 19 February 2019.

REVIEW METHODS

Three reviewers screened the search results. Data were extracted and risk of bias was assessed by one reviewer and checked by the other reviewers. Network meta-analyses were conducted for effectiveness and safety outcomes. Cost-effectiveness was evaluated using an amended version of the Benefits of Smoking Cessation on Outcomes model.

RESULTS

Most monotherapies and combination treatments were more effective than placebo at achieving sustained abstinence. Varenicline standard plus nicotine replacement therapy standard (odds ratio 5.75, 95% credible interval 2.27 to 14.90) was ranked first for sustained abstinence, followed by e-cigarette low (odds ratio 3.22, 95% credible interval 0.97 to 12.60), although these estimates have high uncertainty. We found effect modification for counselling and dependence, with a higher proportion of smokers who received counselling achieving sustained abstinence than those who did not receive counselling, and higher odds of sustained abstinence among participants with higher average dependence scores. We found that bupropion standard increased odds of serious adverse events compared with placebo (odds ratio 1.27, 95% credible interval 1.04 to 1.58). There were no differences between interventions in terms of major adverse cardiovascular events. There was evidence of increased odds of major adverse neuropsychiatric events for smokers randomised to varenicline standard compared with those randomised to bupropion standard (odds ratio 1.43, 95% credible interval 1.02 to 2.09). There was a high level of uncertainty about the most cost-effective intervention, although all were cost-effective compared with nicotine replacement therapy low at the £20,000 per quality-adjusted life-year threshold. E-cigarette low appeared to be most cost-effective in the base case, followed by varenicline standard plus nicotine replacement therapy standard. When the impact of major adverse neuropsychiatric events was excluded, varenicline standard plus nicotine replacement therapy standard was most cost-effective, followed by varenicline low plus nicotine replacement therapy standard. When limited to licensed interventions in the UK, nicotine replacement therapy standard was most cost-effective, followed by varenicline standard.

LIMITATIONS

Comparisons between active interventions were informed almost exclusively by indirect evidence. Findings were imprecise because of the small numbers of adverse events identified.

CONCLUSIONS

Combined therapies of medicines are among the most clinically effective, safe and cost-effective treatment options for smokers. Although the combined therapy of nicotine replacement therapy and varenicline at standard doses was the most effective treatment, this is currently unlicensed for use in the UK.

FUTURE WORK

Researchers should examine the use of these treatments alongside counselling and continue investigating the long-term effectiveness and safety of e-cigarettes for smoking cessation compared with active interventions such as nicotine replacement therapy.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016041302.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 59. See the NIHR Journals Library website for further project information.

Long-Term Outcomes of Real-World Korean Patients with Atrial-Fibrillation-Related Stroke and Severely Decreased Ejection Fraction

BACKGROUND AND PURPOSE

The clinical implications of echocardiography findings for long-term outcomes in atrial fibrillation (AF)-related stroke patients are unknown.

METHODS

This was a substudy of the Korean ATrial fibrillaTion EvaluatioN regisTry in Ischemic strOke patieNts (K-ATTENTION), which is a multicenter-based cohort comprising prospective stroke registries from 11 tertiary centers. Stroke survivors who underwent two-dimensional transthoracic echocardiography during hospitalization were enrolled. Echocardiography markers included the left-ventricle (LV) ejection fraction (LVEF), the left atrium diameter, and the ratio of the peak transmitral filling velocity to the mean mitral annular velocity during early diastole (E/e' ratio). LVEF was categorized into normal (≥55%), mildly decreased (>40% and <55%), and severely decreased (≤40%). The E/e' ratio associated with the LV filling pressure was categorized into normal (<8), borderline (≥8 and <15), and elevated (≥15). Kaplan-Meier and Cox regression analyses were performed for recurrent stroke, major adverse cardiac events, and all-cause death.

RESULTS

This study finally included 1,947 patients. Over a median follow-up of 1.65 years (interquartile range, 0.42-2.87 years), the rates of recurrent stroke, major adverse cardiac events, and all-cause death were 35.1, 10.8, and 69.6 cases per 1,000 person-years, respectively. Multivariable analyses demonstrated that severely decreased LVEF was associated with a higher risks of major adverse cardiac events [hazard ratio (HR), 3.91; 95% confidence interval (CI), 1.58-9.69] and all-cause death (HR, 1.95; 95% CI, 1.23-3.10). The multivariable fractional polynomial plot indicated that recurrent stroke might be associated with a lower LVEF.

CONCLUSIONS

Severe LV systolic dysfunction could be a determinant of long-term outcomes in AF-related stroke.

Nicotine preloading for smoking cessation: the Preloading RCT

BACKGROUND

Nicotine preloading means using nicotine replacement therapy prior to a quit date while smoking normally. The aim is to reduce the drive to smoke, thereby reducing cravings for smoking after quit day, which are the main cause of early relapse. A prior systematic review showed inconclusive and heterogeneous evidence that preloading was effective and little evidence of the mechanism of action, with no cost-effectiveness data.

OBJECTIVES

To assess (1) the effectiveness, safety and tolerability of nicotine preloading in a routine NHS setting relative to usual care, (2) the mechanisms of the action of preloading and (3) the cost-effectiveness of preloading.

DESIGN

Open-label randomised controlled trial with examination of mediation and a cost-effectiveness analysis.

SETTING

NHS smoking cessation clinics.

PARTICIPANTS

People seeking help to stop smoking.

INTERVENTIONS

Nicotine preloading comprised wearing a 21 mg/24 hour nicotine patch for 4 weeks prior to quit date. In addition, minimal behavioural support was provided to explain the intervention rationale and to support adherence. In the comparator group, participants received equivalent behavioural support. Randomisation was stratified by centre and concealed from investigators.

MAIN OUTCOME MEASURES

The primary outcome was 6-month prolonged abstinence assessed using the Russell Standard. The secondary outcomes were 4-week and 12-month abstinence. Adverse events (AEs) were assessed from baseline to 1 week after quit day. In a planned analysis, we adjusted for the use of varenicline (Champix^®; Pfizer Inc., New York, NY, USA) as post-cessation medication. Cost-effectiveness analysis took a health-service perspective. The within-trial analysis assessed health-service costs during the 13 months of trial enrolment relative to the previous 6 months comparing trial arms. The base case was based on multiple imputation for missing cost data. We modelled long-term health outcomes of smoking-related diseases using the European-study on Quantifying Utility of Investment in Protection from Tobacco (EQUIPT) model.

RESULTS

In total, 1792 people were eligible and were enrolled in the study, with 893 randomised to the control group and 899 randomised to the intervention group. In the intervention group, 49 (5.5%) people discontinued preloading prematurely and most others used it daily. The primary outcome, biochemically validated 6-month abstinence, was achieved by 157 (17.5%) people in the intervention group and 129 (14.4%) people in the control group, a difference of 3.02 percentage points [95% confidence interval (CI) -0.37 to 6.41 percentage points; odds ratio (OR) 1.25, 95% CI 0.97 to 1.62; p = 0.081]. Adjusted for use of post-quit day varenicline, the OR was 1.34 (95% CI 1.03 to 1.73; p = 0.028). Secondary abstinence outcomes were similar. The OR for the occurrence of serious AEs was 1.12 (95% CI 0.42 to 3.03). Moderate-severity nausea occurred in an additional 4% of the preloading group compared with the control group. There was evidence that reduced urges to smoke and reduced smoke inhalation mediated the effect of preloading on abstinence. The incremental cost-effectiveness ratio at the 6-month follow-up for preloading relative to control was £710 (95% CI -£13,674 to £23,205), but preloading was dominant at 12 months and in the long term, with an 80% probability that it is cost saving.

LIMITATIONS

The open-label design could partially account for the mediation results. Outcome assessment could not be blinded but was biochemically verified.

CONCLUSIONS

Use of nicotine-patch preloading for 4 weeks prior to attempting to stop smoking can increase the proportion of people who stop successfully, but its benefit is undermined because it reduces the use of varenicline after preloading. If this latter effect could be overcome, then nicotine preloading appears to improve health and reduce health-service costs in the long term. Future work should determine how to ensure that people using nicotine preloading opt to use varenicline as cessation medication.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN33031001.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 41. See the NIHR Journals Library website for further project information.

Comparative Effectiveness and Safety of Rivaroxaban in Adults With Nonvalvular Atrial Fibrillation

BACKGROUND

All evidence regarding benefits and harms of rivaroxaban for stroke prevention has not been appraised yet.

STUDY QUESTION

What are the comparative effectiveness and safety of rivaroxaban in adults with nonvalvular atrial fibrillation?

DATA SOURCES

Randomized controlled trials (RCTs), meta-analyses, and observational studies were identified in several databases in October 2018.

STUDY DESIGN

Rapid review with evidence appraisal using the Grading of Recommendations Assessment, Development and Evaluation working group approach.

RESULTS

Two direct RCTs (23,021 patients) suggest that rivaroxaban is noninferior to warfarin in the prevention of stroke and systemic embolism (pooled relative risk [RR] 0.73, 95% confidence interval [CI], 0.43-1.24), reduces risk of hemorrhagic stroke (RR 0.59, 95% CI, 0.38-0.92), fatal bleeding (RR 0.49, 95% CI, 0.31-0.76), and cardiac arrest (RR 0.45, 95% CI, 0.25-0.82, 2 RCTs), but increases risk of major gastrointestinal bleeding (RR 1.46, 95% CI, 1.19-1.78). In observational studies, rivaroxaban is associated with lower risk of ischemic stroke (RR 0.87, 95% CI, 0.77-0.99, 222,750 patients), acute myocardial infarction (RR 0.61, 95% CI, 0.48-0.78, 73,739 patients), and intracranial hemorrhage (RR 0.64, 95% CI, 0.45-0.92, 197,506 patients) but higher risk of gastrointestinal bleeding (RR 1.30, 95% CI, 1.19-1.42, 188,968 patients) and higher risk of mortality when compared with warfarin in European studies (RR 1.19, 103,270 patients in the UK; RR 2.02, 22,358 patients in Denmark) but lower risk of mortality in Taiwan (RR 0.58, 40,000 patients). Network meta-analyses and observational studies suggest that rivaroxaban is associated with higher risk of bleeding when compared with apixaban (RR 2.14, 72,586 patients), dabigatran (RR 1.24, 67,102 patients), and edoxaban (RR 1.32, 71,683 patients).

CONCLUSIONS

Research on the long-term comparative effectiveness, safety, and effects on quality of life between rivaroxaban and other novel oral anticoagulants is urgently needed.

Patient screening for early detection of aortic stenosis (AS)-review of current practice and future perspectives

In Europe, approximately one million people over 75 years suffer from severe aortic stenosis (AS), one of the most serious and most common valve diseases, and this disease burden is increasing with the aging population. A diagnosis of severe symptomatic AS is associated with an average life expectancy of 2-3 years and necessitates a timely valve intervention. Guidelines for valve replacement therapy have been established but only a proportion of patients with symptomatic AS actually receive this life-saving treatment. The decision for valve intervention in asymptomatic patients with severe AS is often more challenging and likely results in fewer patients receiving treatment in comparison to their symptomatic counterparts. This article reviews the epidemiology and clinical manifestations of AS, the associated economic burden of AS to the healthcare system, the diagnosis of AS and the possible mechanisms for the introduction of routine screening in elderly patients. Elderly patients typically visit healthcare providers more frequently than younger patients, thereby providing increased opportunities for ad hoc AS screening and this, along with raising patient awareness of the symptoms of AS, has the potential to result in the earlier diagnosis and treatment of AS and increased patient survival.

Is echocardiography valid and reproducible in patients with atrial fibrillation? A systematic review

Aims

Echocardiography is vital in the routine assessment and management of atrial fibrillation (AF). We performed a systematic review of the validity and reproducibility of echocardiographic left ventricular systolic and diastolic function in AF, and optimal acquisition methods.

Methods and results

Online databases were searched for studies in patients with AF at the time of echocardiography (1960 to August 2015), prospectively registered with PROSPERO (CRD42015025297). The systematic review included 32 studies from 3 066 search results (1 968 patients with AF). Average age was 67 years, 33% were women, mean LVEF 53% (±10%), and average E/e’ 11.7 (±2.7). Data on the validity and reproducibility of systolic indices were extremely limited. In contrast, diastolic parameters demonstrated correlation with invasive filling pressure and adequate reproducibility: E/e’ (n = 444) r = 0.47 to 0.79; IVRT (n = 177) r = –0.70 to –0.95; E/Vp` (n = 55) r = 0.63 and 0.65; pulmonary vein diastolic flow (n = 67) r = –0.80 and –0.91. Elevated E/e’ (>15) was associated with functional capacity, quality of life, and impaired prognosis. For optimal acquisition in AF patients, cardiac cycles with controlled heart rate (<100 beats/min) and similar preceding and pre-preceding RR intervals are required. Cardiac cycle length and equivalence were more important than the number of beats averaged.

Conclusion

With careful selection of appropriate cardiac cycles, echocardiography is a valid tool to identify diastolic dysfunction in AF, and E/e’ is an independent marker of clinical status and adverse prognosis. However, data on systolic function was extremely limited and requires further prospective study and assessment of variability in clinical practice.

Evidence synthesis to inform model-based cost-effectiveness evaluations of diagnostic tests: a methodological review of health technology assessments

BACKGROUND

Evaluations of diagnostic tests are challenging because of the indirect nature of their impact on patient outcomes. Model-based health economic evaluations of tests allow different types of evidence from various sources to be incorporated and enable cost-effectiveness estimates to be made beyond the duration of available study data. To parameterize a health-economic model fully, all the ways a test impacts on patient health must be quantified, including but not limited to diagnostic test accuracy.

METHODS

We assessed all UK NIHR HTA reports published May 2009-July 2015. Reports were included if they evaluated a diagnostic test, included a model-based health economic evaluation and included a systematic review and meta-analysis of test accuracy. From each eligible report we extracted information on the following topics: 1) what evidence aside from test accuracy was searched for and synthesised, 2) which methods were used to synthesise test accuracy evidence and how did the results inform the economic model, 3) how/whether threshold effects were explored, 4) how the potential dependency between multiple tests in a pathway was accounted for, and 5) for evaluations of tests targeted at the primary care setting, how evidence from differing healthcare settings was incorporated.

RESULTS

The bivariate or HSROC model was implemented in 20/22 reports that met all inclusion criteria. Test accuracy data for health economic modelling was obtained from meta-analyses completely in four reports, partially in fourteen reports and not at all in four reports. Only 2/7 reports that used a quantitative test gave clear threshold recommendations. All 22 reports explored the effect of uncertainty in accuracy parameters but most of those that used multiple tests did not allow for dependence between test results. 7/22 tests were potentially suitable for primary care but the majority found limited evidence on test accuracy in primary care settings.

CONCLUSIONS

The uptake of appropriate meta-analysis methods for synthesising evidence on diagnostic test accuracy in UK NIHR HTAs has improved in recent years. Future research should focus on other evidence requirements for cost-effectiveness assessment, threshold effects for quantitative tests and the impact of multiple diagnostic tests.

Association of the CHADS2 and CHA 2DS 2-VASc scores with left atrial enlargement: a prospective cohort study of unselected atrial fibrillation patients

Assessment of thromboembolic risk is crucial for proper management of atrial fibrillation (AF) patients. Currently used risk score base only on scarce clinical data and do not take into consideration parameters including echocardiographic findings. The aim of this study was to evaluate if left atrium (LA) enlargement is associated with higher thromboembolic risk assessed by CHADS₂ and CHA₂DS₂-VASc scores in a cohort of unselected non-valvular AF patients. Data from 582 AF hospitalizations occurring between November 2012 and January 2014 were analyzed. All patients underwent a standard transthoracic echocardiography and had their thromboembolic risk assessed in both CHADS₂ and CHA₂DS₂-VASc scores. In 494 enrolled patients (48.5 % male; mean age 73.4 ± 11.5 years) AF was classified as paroxysmal in 233 (47.3 %), as persistent in 109 (22.1 %), and as permanent in 151 (30.6 %) patients. LA was enlarged in 426 (86.2 %) patients. Enlargement was classified as mild in 99 (20.0 %) patients, as moderate in 130 (26.3 %) patients, and as severe in 196 (39.7 %) patients. Patients with enlarged LA had higher mean CHADS₂ score (2.0 ± 1.5 vs. 2.6 ± 1.3; p = 0.0005) and CHA₂DS₂-VASc (3.8 ± 2.0 vs. 4.4 ± 1.8; p = 0.02) score than patients with normal LA. The both mean scores rose along with rising LA diameter. LA enlargement is highly prevalent in AF patients. Higher thromboembolic risk assessed by both CHADS₂ and CHA₂DS₂-VASc scores is associated with presence of LA enlargement. Echocardiographically assessed LA size may be an additional parameter useful in thromboembolic risk stratification of AF patients.

Improving search efficiency for systematic reviews of diagnostic test accuracy: an exploratory study to assess the viability of limiting to MEDLINE, EMBASE and reference checking

BACKGROUND

Increasing numbers of systematic reviews evaluating the diagnostic test accuracy of technologies are being published. Currently, review teams tend to apply conventional systematic review standards to identify relevant studies for inclusion, for example sensitive searches of multiple bibliographic databases. There has been little evaluation of the efficiency of searching only one or two such databases for this type of review. The aim of this study was to assess the viability of an approach that restricted searches to MEDLINE, EMBASE and the reference lists of included studies.

METHODS

A convenience sample of nine Health Technology Assessment (HTA) systematic reviews of diagnostic test accuracy, with 302 included citations, was analysed to determine the number and proportion of included citations that were indexed in and retrieved from MEDLINE and EMBASE. An assessment was also made of the number and proportion of citations not retrieved from these databases but that could have been identified from the reference lists of included citations.

RESULTS

287/302 (95 %) of the included citations in the nine reviews were indexed across MEDLINE and EMBASE. The reviews' searches of MEDLINE and EMBASE accounted for 85 % of the included citations (256/302). Of the forty-six (15 %) included citations not retrieved by the published searches, 24 (8 %) could be found in the reference lists of included citations. Only 22/302 (7 %) of the included citations were not found by the proposed, more efficient approach.

CONCLUSIONS

The proposed approach would have accounted for 280/302 (93 %) of included citations in this sample of nine systematic reviews. This exploratory study suggests that there might be a case for restricting searches for systematic reviews of diagnostic test accuracy studies to MEDLINE, EMBASE and the reference lists of included citations. The conduct of such reviews might be rendered more efficient by using this approach.