A systematic literature review of the National Early Warning Score (NEWS)-2 using Prediction Model Risk of Bias Assessment Tool (PROBAST)

BackgroundIdentifying patients who are at risk of deteriorating to prevent avoidable complications is a challenge for health management. To support clinical decision-making, the UK introduced the National Early Warning Score 2 (NEWS-2). However, effectiveness in hospitals is not well understood. ObjectiveTo perform a systematic review of external validation studies of NEWS-2. MethodsWe performed a systematic review of NEWS-2 and a critical appraisal using PROBAST. Following PRISMA guidelines we searched Medline, Embase, Global Health and Social Policy and Practice for UK NEWS-2 external validation studies from January 2017 to November 2023. PROBAST was used to assess Risk-of-Bias (ROB), segmenting results by population level and model characteristics. Results31 validation studies were included in the final sample, including 19 from the UK, nine from Spain, one from Denmark and two from Sweden. 29 out of the 31 studies included were considered to have a high ROB with one having high risk of applicability. The main sources of bias were analytical weaknesses (n=29), outcome measures (n=8), weak inclusion/exclusion of participants (n=5) and weak predictors (n=2). ConclusionsMost external validation studies of NEWS-2 have a high ROB. Future research is needed to address methodological weaknesses, particularly in predictors measurement, the inclusion of outcomes in the predictor measures, missing data, and inadequate calibration. These findings could help inform future Royal College of Physicians (RCP) policy reviews of NEWS-2. RegistrationNot registered, the protocol was not prepared. Guarantor of the workCidalia Eusebio Social media abstractThe high risk of bias in studies evaluating NEWS-2 means we should use caution not to rely on NEWS -2 alone for clinical decision making. #PatientSafety @eusebiocidalia @alisonleary1 @davidstuckler ImpactO_LINEWS-2 was introduced in UK hospitals in 2017, but its effectiveness is unclear. C_LIO_LIWe performed a critical appraisal of NEWS-2 in hospital and pre-hospital settings. C_LIO_LIDespite having a high ROB in the literature, NEWS-2 is utilised in the NHS. C_LIO_LIClinicians should be cautious about relying solely on NEWS-2 for making decisions. C_LIO_LIOxygen scores based on increase oxygen requirements should be reevaluated. C_LIO_LIThis review supports reinstating the NEWS-2 policy review by the RCP, which was cancelled in 2023. C_LI Reporting MethodWe adhered to the relevant EQUATOR guidelines. Patient or Public ContributionThere was no patient or public contribution.