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Original article
Comparison of early warning scores in patients with COPD exacerbation: DECAF and NEWS score
  1. Carlos Echevarria1,2,
  2. John Steer1,3,
  3. Stephen C Bourke1,3
  1. 1 Newcastle University, Newcastle upon Tyne, UK
  2. 2 Respiratory Medicine, Royal Victoria Infimrary, Newcastle upon Tyne, UK
  3. 3 Respiratory Medicine, North Tyneside General Hospital, North Shields, UK
  1. Correspondence to Prof Stephen C Bourke, Respiratory Medicine, North Tyneside General Hospital, North Shields NE29 8NH, UK; stephen.bourke{at}nhct.nhs.uk

Abstract

Background The National Early Warning Score 2 (NEWS2) includes two oxygen saturation scales; the second adjusts target saturations to 88%–92% for those with hypercapnic respiratory failure. Using this second scale in all patients with COPD exacerbation (‘NEWS2All COPD’) would simplify practice, but the impact on alert frequency and prognostic performance is unknown. Admission NEWS2 score has not been compared with DECAF (dyspnoea, eosinopenia, consolidation, acidaemia, atrial fibrillation) for inpatient mortality prediction.

Methods NEWS, NEWS2 and NEWS2All COPD and DECAF were calculated at admission in 2645 patients with COPD exacerbation attending consecutively to one of six UK hospitals, all of whom met spirometry criteria for COPD. Alert frequency and appropriateness were assessed for all NEWS iterations. Prognostic performance was compared using the area under the receiver operating characteristic (AUROC) curve. Missing data were imputed using multiple imputation.

Findings Compared with NEWS, NEWS2 reclassified 3.1% patients as not requiring review by a senior clinician (score≥5). NEWS2All COPD reduced alerts by 12.6%, or 16.1% if scoring for injudicious use of oxygen was exempted. Mortality was low in reclassified patients, with no patients dying the same day as being identified as low risk. NEWS2All COPD was a better prognostic score than NEWS (AUROC 0.72 vs 0.65, p<0.001), with similar performance to NEWS2 (AUROC 0.72 vs 0.70, p=0.090). DECAF was superior to all scores (validation cohort AUROC 0.82) and offered a more clinically useful range of risk stratification (DECAF=1.2%–25.5%; NEWS2=3.5%–15.4%).

Conclusion NEWS2All COPD safely reduces the alert frequency compared with NEWS2. DECAF offers superior prognostic performance to guide clinical decision-making on admission, but does not replace repeated measures of NEWS2 during hospitalisation to detect the deteriorating patient.

  • copd exacerbations
  • copd epidemiology

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Footnotes

  • Contributors The study was conceived by SCB and designed by CE, JS and SCB. CE performed the statistical analyses. All authors contributed to data analysis and interpretation, and all were involved in drafting the manuscript and approving the final version. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

  • Funding Department of Health, Breathe North appeal, Northumbria NHS Foundation Trust Teaching and Research Fellowship programme and Novartis Pharmaceuticals UK.

  • Disclaimer The funders of the study had no role in study design, data collection, data analysis, data interpretation or writing of the report.

  • Competing interests All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: JS has no conflicts of interest to declare. CE reports grants from National Institute of Health Research, outside of the submitted work. SCB reports grants from National Institute of Health Research, Philips Respironics and from Pfizer Open Air, personal fees from Pfizer, AstraZeneca and ResMed, and non-financial support from Boehringer Ingelheim and GlaxoSmithKline outside the submitted work. No author has financial relationships with any organisation that might have an interest in the submitted work.

  • Patient consent for publication Not required.

  • Ethics approval The study was approved by NRES Committee North East, UK (REC reference: 12/NE/0379).

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

  • Data availability statement Data are available on reasonable request.

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