What is Real World Evidence?
Written by Dr Niamh O’Reilly

Real-world evidence (RWE) is evidence relating to the use and potential benefits and risks of a therapeutic product derived from analysis of real-world data (RWD) from multiple sources. RWD may be derived from sources such as product and disease registries, electronic health records (EHR), insurance claims, pharmacy records, patient generated data (e.g. patient reported outcomes, surveys), social media and sensor outputs from devices.1,2 RWE is increasingly used to complement data from randomised controlled trials (RCT) and therefore bridge the gap in knowledge between clinical trials and clinical practice. RWE can be used to inform stakeholder understanding of the patient journey, generate meaningful insights into unmet medical needs and enable analysis of the clinical and economic impact of therapies on patients and healthcare systems.3


Types of RWD

Source Description
Clinical EHR data, test results, radiology images, histology, procedures, provider notes, admission/discharge and progress reports
Claims Database Medical claims, prescription claims, other drug and treatment use data
Molecular Profiling Genomic and genetic testing, biomarker status
Mobile Health Data from wearable devices, fitness trackers, health apps measuring activity and body function
Environmental Lifestyle factors (diet, stress), pollutants, infections, other environmental and occupational sources
Patient Reported Patient reported outcomes, surveys, diaries (diet, habits), personal health records, adverse event reporting, quality of life measurements
Social Media Patient communities, Twitter, Facebook, blogs
Literature Disease burden, clinical characteristics, prevalence/incidence, rates of treatment, resource use and costs, disease control, quality of life measures

Adapted from Swift et al. 2



RCTs are considered the gold standard for approval of new therapies and remain fundamental to evaluating the safety and efficacy of new drugs. However, they are often subject to selection bias whereby patients with chronic illness or other comorbidities and elderly patients may not be represented in clinical trials. For example, less than 5% of adult patients with cancer participate in clinical trials and they tend to be younger, healthier and less diverse than the general population. 4 In some cases conventional RCTs alone may not provide sufficient evidence of the relative effectiveness of a therapy to support reimbursement decision-making. A well designed RWE study can supplement the body of clinical evidence to confirm the efficacy and safety of therapies among a broad patient population in routine clinical practice.


Standard of Evidence Complementary to RCT Gold standard
Purpose Effectiveness Efficacy
Patient Population Large sample size, limited selection, evaluates patients not typically studied in clinical trials Limited sample size, highly selective, well defined within specific eligibility criteria
Treatment Selection Uncontrolled Controlled by randomisation
Treatment As in clinical practice Restricted by the protocol
Toxicity Helps uncover important toxicity signals requiring long term follow up Only acute and common toxicities are revealed
Outcome Often observed indirectly Directly observed
External Validity High Limited
Data Quality Low High
Cost of Treatment Observable Unknown
Direct Comparisons Invalid due to confounding Valid due to randomisation
Approval of New Therapies Not always suitable for approving interventions but helpful to validate RCT findings Considered the gold standard for new drug approvals

Adapted from multiple sources. 1,3,4


Benefits and Limitations of RWE

The use of RWE in drug development decision-making may enable innovation in clinical programs and trial designs which could potentially reduce the cost of drug development. 2 RWE can be used to provide clinicians with insights into how patients will respond to treatment interventions in everyday clinical practice. For example, a large real-world analysis of a monoclonal antibody therapy for treatment of people with psoriasis provided evidence that could not be collected during previous RCTs due to strict inclusion criteria.5 The RWE included patients with a range of transition periods (between prior treatment and the new therapy) and those using concomitant treatments and confirmed the safety and effectiveness of the therapy in a diverse range of patients.5

RWE can also be leveraged by manufacturers to obtain market access, while payers may use it to substantiate pricing and reimbursement. Therefore, RWE can be beneficial in helping payers and manufacturers to implement performance-based risk-sharing agreements which are increasingly common as many jurisdictions move to implement value based healthcare systems.2 However, there are challenges associated with using RWE such as data collection, data quality, developing data analysis methods to mitigate possible biases and protecting patient privacy. These challenges need to be overcome before stakeholders can realise the full potential of RWE to improve clinical practice and help provide safe, effective therapies to the right patients at the right time.


CRCs experienced Medical Affairs team has the expertise to generate RWE data and insights using a variety of methods to maximise therapy value and support Medical Affairs and Market Access related projects.




  1. Klonoff D.C. et al. Real-World Evidence Should Be Used in Regulatory Decisions About New Pharmaceutical and Medical Device Products for Diabetes. Available at: https://bit.ly/2KbBOu1
  2. Swift B. et al. Innovation at the Intersection of Clinical Trials and Real-World Data Science to Advance Patient Care. 2018. Available at: https://bit.ly/2wQUGWs
  3. Anbil P. S. Is There Evidence in Real-World Evidence? 2019. PharmExec. Available at: https://bit.ly/2ULE9h0
  4. Gyawali B. et al, Real-World Evidence and Randomized Studies in the Precision Oncology Era: The Right Balance. 2018. ASCO. Available at: https://bit.ly/2I1j3XZ
  5. Novartis real-world evidence confirms efficacy and safety benefits of Cosentyx® in daily life for psoriasis patients. 2018. Available at: https://bit.ly/2Cv3LZ0