Predicting COPD exacerbations: Saint George's defeats classic chronic bronchitis definition

  • Kim V & al.
  • Chest
  • 29 Apr 2019

  • International Clinical Digest
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Takeaway

  • For predicting COPD exacerbations, the Saint George's Respiratory Questionnaire (SGRQ) definition of chronic bronchitis (CB) might be better than the classic CB definition.
  • In this comparison, only CB by SGRQ was independently linked to severe exacerbations.

Why this matters

  • CB affects about 10 million people in the United States.
  • People with COPD who also have CB tend to fare worse.
  • How well SGRQ captures CB and predicts COPD exacerbation has not been established.

Key results

  • CB by either definition was linked to increased risk for more and severe exacerbations during the 5.16-year follow-up.
  • SGRQ bested the classic definition on multivariate analysis as an independent predictor for frequency:
    • Classic: β coefficient, 0.083; P=.006; and 
    • SGRQ: β, 0.166; P<.0001.>
  • It also was the only 1 of the 2 to be independently associated with severe exacerbation frequency:
    • Classic: β coefficient, 0.032 (P=.054); and
    • SGRQ: β, 0.065 (P<.0001>

Study design

  • Study included 7557 smokers with COPD, normal spirometry, all part of the COPDGene study.
  • Classic definition: chronic cough, sputum for 3 months/year, at least 2 consecutive years.
  • SBRQ: uses answers to questions about cough and phlegm.
  • Funding: National Heart, Lung, and Blood Institute; some industry funding for the COPDGene study.

Limitations

  • Exacerbations self-reported.