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Strengths and weaknesses of ‘real-world’ studies involving non-vitamin K antagonist oral anticoagulants
  1. A John Camm1,2 and
  2. Keith A A Fox3
  1. 1 Molecular and Clinical Sciences Institute, St George’s University of London, London, UK
  2. 2 Molecular and Clinical Sciences Institute, Imperial College, London, UK
  3. 3 Centre for Cardiovascular Science, University of Edinburgh and Royal Infirmary of Edinburgh, Edinburgh, UK
  1. Correspondence to Professor A John Camm; submissions2017{at}


Randomised controlled trials (RCTs) provide the reference standard for comparing the efficacy of one therapy or intervention with another. However, RCTs have restrictive inclusion and exclusion criteria; thus, they are not fully representative of an unselected real-world population. Real-world evidence (RWE) studies encompass a wide range of research methodologies and data sources and can be broadly categorised as non-interventional studies, patient registries, claims database studies, patient surveys and electronic health record studies. If appropriately designed, RWE studies include a patient population that is far more representative of unselected patient populations than those of RCTs, but they do not provide a robust basis for comparing treatment strategies. RWE studies can have very large sample sizes, can provide information on treatments in patient groups that are usually excluded from RCTs, are generally less expensive and quicker than RCTs, and can assess a broad range of outcomes. Limitations of RWE studies can include low internal validity, lack of quality control surrounding data collection and susceptibility to multiple sources of bias for comparing outcomes. RWE studies can complement the findings from RCTs by providing valuable information on treatment practices and patient characteristics among unselected patients. This information is necessary to guide treatment decisions and for reimbursement and payment decisions. RWE studies have been extensively applied in the postmarketing approval assessment of non-vitamin K antagonist oral anticoagulants since 2010. However, the benefits, costs, limitations and methodological challenges associated with the different types of RWE must be considered carefully when interpreting the findings.

  • anticoagulant
  • limitations
  • real-world evidence

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  • Contributors AJC and KAAF both contributed to the drafting of the manuscript.

  • Funding Funding for editorial support was provided by Bayer AG.

  • Competing interests AJC has received research grants and speaker’s honoraria, and participated in scientific advisory boards for Bayer, Daiichi Sankyo, Bristol-Myers Squibb-Pfizer and Boehringer Ingelheim. KAAF has received grants and honoraria from Bayer and Janssen.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data are available.