Are within-person numerical rating scale (NRS) ratings of breathlessness “on average” valid in advanced disease for patients and for patients’ informal carers?

Joshua Wade, Silvia Mendonca, Sara Booth, Gail Ewing, Carole Gardener, Morag Farquhar

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Introduction: The Numerical Rating Scale (NRS) is frequently used to assess patient reported breathlessness in both a research and clinical context. A subgroup report average breathlessness as worse than worst breathlessness in the last 24 hours. The Peak/End rule describes how the most extreme and current breathlessness influence reported average. This study seeks to highlight the existence of a subpopulation who give ‘paradoxical averages using the NRS, to characterise this group and to investigate the explanatory relevance of the ‘Peak/End’ rule. Methods: Data were collected within mixed method face-to-face interviews for three studies: the Living with Breathlessness Study and the two sub-protocols of the Breathlessness Intervention Service Phase III randomised controlled trial. Key variables from the three datasets were pooled (n=561) and cases where participants reported a paradoxical average (n=45) identified. These were compared to non-cases and interview transcripts interrogated. NRS rating of average breathlessness were assessed for fit to Peak/End rule. Results: Patients in the paradoxical average group had higher Chronic Respiratory Questionnaire physical domain scores on average p=0.042). Peak/End rule analysis showed high positive correlation (Spearman’s rho= 0.756, p<0.001). Conclusions: The NRS requires further standardisation with reporting of question order and construction of scale used to enable informed interpretation. The application of the Peak/End rule demonstrates fallibility of NRS-Average as a construct as it is affected by current breathlessness. Measurement of breathlessness is important for both clinical management and research, but standardisation and transparency is required for meaningful results.
Original languageEnglish
Article numbere000235
JournalBMJ Open Respiratory Research
Issue number1
Publication statusPublished - 11 Oct 2017


  • Breathlessness
  • Numerical Rating Scale
  • Dyspnoea
  • Peak/End rule

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