Early warning scores for detecting deterioration in adult hospital patients: systematic review and critical appraisal of methodologyBMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m1501 (Published 20 May 2020) Cite this as: BMJ 2020;369:m1501
All rapid responses
As co-developers of the first early warning score (EWS), it is of concern to read yet another article misrepresenting the purpose of the EWS . As was mentioned in our similar response in 2007, the EWS was never intended to be a predictive score, it could not be. The score based on aggregate weighted scoring of physiological variables, was designed solely with the purpose of empowering frontline inexperienced staff to ensure timely expert clinical assistance at the bedside of a patient exhibiting deranged physiology, which could signify established or impending critical illness. Hence the use of the word 'early'. The overall course for most critically ill patients is punctuated by multiple potential confounding influences making any final outcome predictions based on simple routine bedside measurements impossible.
The EWS has been modified and refined many times from the original, including specialty specific and non-weighted variations. These multiple variants of the simple basic original system make comparisons, as undertaken in the current review, inherently challenging. There is no doubt that unless universally adopted in an institution or indeed Health system as recommended by NICE, physiological recordings and EWS implementation will be inaccurate and incomplete as was found in this article.
To criticise the EWS as an ineffective and potentially harmful predictor of eventual outcome is to miss the point of its simplicity, its timely role in the clinical course of severe illness, the impact of its methodical application and the fact that it was never intended to be a predictive score. It is a physiological aggregate weighted track and trigger score .
Whatever variant of the basic physiological track and trigger principle is selected, the agreed ‘trigger’ threshold represents a value, which if reached or exceeded, is an instantaneous ‘red flag’ mandating the physical attendance of an experienced clinician by the bedside.
A deteriorating score, as represented by an increase in score over time, is also a vital part of the tool (the tracking bit) whatever the absolute initial or subsequent values may be.
What the EWS has notably achieved in the UK is vastly improved monitoring of all patients. Its electronic adaption where available has increased accuracy and often decreased workload. It has also led to a far greater appreciation by all clinical staff that physiological parameters require accurate measurement and recording and where deranged require attention and clinical expertise to decide on timely optimal clinical management. NCEPOD in their 2018 Themes report recommended the use of the NEWS based on 18 years of reviewing the case notes of 25,018 patients .
1 Morgan RJM, Williams F, Wright MM. An early warning scoring system for detecting developing critical illness, Clin.Intensive Care, 1997, vol.8 pg.100.
2 Morgan RJM, Wright MM. In defence of early warning scores. BJA: Vol.99, Issue 5, November 2007, p 747-748
3 NICE Clinical Guideline 50. Acutely ill patients in hospital. BMJ 2007;335:258
4 NCEPOD: Common Themes Report, November 2018
Competing interests: No competing interests
Early warning scores use routinely collected vital signs data to generate a composite score which reflects the disturbance of a patient’s physiology from normal and as such, are an index of illness severity (1). They are promoted as an aid to clinical assessment to help recognise clinical illness severity or acute clinical deterioration, as part of routine clinical monitoring, prompting an appropriate clinical response.
Gerry et al’s (2) critical appraisal of evaluation methods for early warning scores is welcome but makes unsubstantiated and misleading claims which must be challenged. To state that EWSs could have a highly detrimental effect on patient care when these are routine clinical measurements that supplement clinical judgement is alarmist, unsubstantiated and wrong. They present no evidence of a “detrimental effect”. As practising clinicians, we use these measures on a daily basis, they help us prioritise the timely review of the sickest patients and provide appropriate management plans. We also find that our nursing colleagues feel empowered to raise their concerns through the escalation routes that this approach has enabled.
The authors also state clinicians should be cautious about relying on these scores to identify clinical deterioration in patients. All of the training and support materials for NEWS2 emphasise that this is designed to supplement clinical judgement and that clinical concern alone is a cause for escalation, whatever the NEWS2 score (3,4). Again, the authors do not present evidence that clinicians “rely” on these scores to identify clinical deterioration in patients. The Royal College of Physicians has never advocated “medicine by numbers” or that such systems should be used in isolation from clinical judgement.
The authors also state that the NEWS was developed by clinical consensus rather than by applying statistical methods, which is the usual method for developing prediction models. The development of the NEWS and NEWS2 has been described in detail in the NEWS and NEWS2 publications and was based on allocating weighting scores to variations in physiology from the norm and then validating the scoring system using an extensive NHS hospital clinical database of bed-side physiological measurements, linked to a range of clinical outcomes, including death within 24 hours of assessment (1,3,5). This initial evaluation of the NEWS, supporting the recommendations in the original NEWS report, was subsequently published. Since publication of the NEWS, further evaluations of the performance of NEWS have been reported, from independent research groups, in undifferentiated patients across in a variety of care settings in the NHS and across the world. The NEWS is by far the most validated system in clinical use.
The NEWS/NEWS2 has been widely deployed in the NHS and across the world and there are now numerous examples of its use being associated with improvements in the clinical response to deteriorating patients and patient outcomes (5-15). Alert, track and trigger systems need to be based on routinely collected vital signs, simple to use, familiar and instantly recognisable and embedded across the health care system. Staff have recognised the importance of a single system, that facilitates training and communication of illness severity because everybody is speaking the same “language” (3,4,16,17). It is this standardisation of approach that, using a well-recognised and externally validated system, that delivers a step change in patient safety. Continuing research on reliable and successful implementation that delivers these outcomes will always be necessary.
1. Royal College of Physicians. National Early Warning Score (NEWS) 2: Standardising the assessment of acute-illness severity in the NHS. Updated report of a working party. London: RCP, 2017.
2. Gerry S, Birks J, Bonnici T, et alEarly warning scores for detecting deterioration in adult hospital patients: a systematic review and critical appraisal of methodology. protocol; BMJ 2020;369:m1501
3. Royal College of Physicians. https://www.rcplondon.ac.uk/projects/outputs/national-early-warning-scor... (Accessed 28 May 2020)
4. Inada-Kim Matt, Nsutebu Emmanuel. NEWS 2: an opportunity to standardise the management of deterioration and sepsis BMJ 2018; 360 :k1260
5. Smith GB, Prytherch DR, Jarvis S et al. A comparison of the ability of the physiologic components of Medical Emergency Team criteria and the U.K. National Early Warning Score to discriminate patients at risk of a range of adverse clinical outcomes. Crit Care Med 2016;44:2171–81.
6. Bilben B, Grandal L, Søvik S. National Early Warning Score (NEWS) as an emergency department predictor of disease severity and 90-day survival in the acutely dyspneic patient – a prospective observational study. Scand J Trauma Resusc Emerg Med 2016;24:80.
7. Smith GB, Prytherch DR, Meredith P, Schmidt PE, Featherstone PI. The ability of the National Early Warning Score (NEWS) to discriminate patients at risk of early cardiac arrest, unanticipated intensive care unit admission, and death. Resuscitation 2013;84:465–70.
8. Roberts D, Djärv T. Preceding national early warnings scores among in-hospital cardiac arrests and their impact on survival. Am J Emerg Med 2017;35:1601–6.
9. Kovacs C, Jarvis SW, Prytherch DR et al. Comparison of the National Early Warning Score in non-elective medical and surgical patients. Br J Surg 2016;103:1385–93.
10. Scott L, Redmond, Tavaré A, Little H, Srivastava S and Pullyblank A; Association between National Early Warning Scores in primary care and clinical outcomes: Br J Gen Pract 2020; DOI: https://doi.org/10.3399/bjgp20X709337
11. Inada-Kim M, Knight T, Sullivan M, Ainsworth-Smith M, Pike N, Richardson M, Hayward G, Lasserson D; The prognostic value of national early warning scores (NEWS) during transfer of care from community settings to hospital: a retrospective service evaluation; BJGP Open 12 May 2020; bjgpopen20X101071. DOI: 10.3399/bjgpopen20X101071
12. Shaw J, Fothergill RT, Clark S, Moore F. Can the prehospital National Early Warning Score identify patients most at risk from subsequent deterioration? Emerg Med J 2017;34:533–7. https://doi.org/10.1136/emermed-2016-206115
13. Silcock DJ, Corfield AR, Gowens PA, Rooney KD. Validation of the National Early Warning Score in the prehospital setting. Resuscitation 2015;89;31–5. https://doi.org/10.1016/j.resuscitation.2014.12.029
14. Hodgson LE, Dimitrov BD, Congleton J et al. A validation of the National Early Warning Score to predict outcome in patients with COPD exacerbation. Thorax 2017;72:23–30. https://doi.org/10.1136/thoraxjnl-2016-208436
15. Hancock C. A national quality improvement initiative for reducing harm and death from sepsis in Wales. Intensive Crit Care Nurs 2015;31:100–5.
16. NHS England, NHS Improvement and RCP. Patient Safety Alert: Resources to support the safe adoption of the revised National early Warning Score (NEWS2) 2018. https://improvement.nhs.uk/documents/2508/Patient_Safety_Alert_-_adoptio...
17. Goodwin APL, Srivastava V, Shotton H et al. Just Say Sepsis! A review of the process of care received by patients with sepsis. A report by the National Confidential Enquiry into Patient Outcome and Death. London: NCEPOD, 2015. www.ncepod.org.uk/2015sepsis.html
Competing interests: No competing interests
Re: Early warning scores for detecting deterioration in adult hospital patients: systematic review and critical appraisal of methodology
Early warning scores: is it too late for randomised controlled trials?
The excellent paper by Gerry et al , highlights the dearth of evidence from clinical trials for deployment of early warning scores (EWS). Nurses’ timely recognition and reporting of clinical deterioration is crucial for patient survival: delays are sometimes attributable to human-related monitoring failures [2,3].
The adoption of EWS was based on large observation studies in developed countries , and this important analysis  suggests that large pragmatic randomised controlled trials (RCTs) are still needed to ensure that patient safety is optimised. We undertook two small RCTs of a modified EWS (MEWS) in Cape Town. The first trial in one hospital indicated the need for a multi-centre trial . The multi-centre trial offered limited support for the assumed superiority of EWS/MEWS over traditional pen and paper run charts: assistance was summoned for fewer patients with abnormal vital signs in the intervention (MEWS) arm (2/45, 4.4% vs 11/81, 13.6%, OR 0.29 [0.06-1.39]), particularly low systolic blood pressure . We attributed this, in part, to nurses not receiving full training in use of the MEWS, because they could not be released from ward duties. This ‘no benefit’ conclusion can only be extended to the same or similar settings and conditions pertaining to this trial. However, our RCTs offer useful learning for those embarking on future trials on recording of clinical deterioration: whatever system is used, clinical effectiveness and patient safety depend on nurses’ understanding and application of clinical physiology, particularly during transition between systems [7-9].
As electronic EWS are implemented, is it too late to subject them to pragmatic stepped wedge randomised controlled trials?
1. Gerry Stephen, Bonnici Timothy, Birks Jacqueline, Kirtley Shona, Virdee Pradeep S, Watkinson Peter J et al. Early warning scores for detecting deterioration in adult hospital patients: systematic review and critical appraisal of methodology BMJ 2020; 369 :m1501
2. van Galen LS, Struik PW, Driesen BE, Merten H, Ludikhuize J, van der Spoel JI, Kramer MH, Nanayakkara PW: Delayed Recognition of Deterioration of Patients in General Wards Is Mostly Caused by Human Related Monitoring Failures: A Root Cause Analysis of Unplanned ICU Admissions. PLoS One 2016, 11:e0161393.
3. Kyriacos U, Jelsma J, Jordan S Record Review to Explore the Adequacy of Post-Operative Vital Signs Monitoring Using a Local Modified Early Warning Score (Mews) Chart to Evaluate Outcomes. PLoS ONE 2014 9(1): e87320. doi:10.1371/journal.pone.0087320
4. Royal College of Physicians. Royal College of Physicians National Early Warning Score (NEWS) 2: Standardising the assessment of acute-illness severity in the NHS. Updated report of a working party.RCP, 2017.
5. Una Kyriacos, Jennifer Jelsma, Michael James and Sue Jordan 2015 Early warning scoring systems versus standard observations charts for wards in South Africa: a cluster randomised controlled trial. Trials.2015, 16:103 DOI: 10.1186/s13063-015-0624-2 URL:
6. Kyriacos U, Burger D, Jordan S. Testing effectiveness of the revised Cape Town modified early warning and SBAR systems: a pilot pragmatic parallel group randomised controlled trial. Trials. 2019 Dec 30;20(1):809. doi: 10.1186/s13063-019-3916-0.
7. Jordan S. and Reid K. The biological sciences in nursing: an empirical paper reporting on the applications of physiology to nursing care. Journal of Advanced Nursing: 1997 : 26 : 1 : 169-179
8. Kyriacos U., Jordan S., Van den Heever J. The Biological Sciences In Nursing: A Developing Country Perspective. Journal of Advanced Nursing. 2005: 52(1), 91-103
9. Jordan S., Davies S. and Green B. The Biosciences in the Pre-registration Nursing Curriculum: staff and students’ perceptions of difficulties and relevance. Nurse Education Today: 1999: 19 : 3 : 215-26
Competing interests: No competing interests