diagnosis of COPD must have airflow obstruction

• related: COPD chronic obstructive pulmonary disease
• tags: #permanent

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Presence of COPD is suggested by three things:

• Symptoms of dyspnea, cough, sputum production
• Image finding of airway abnormality (bronchitis, bronchiolitis) or alveoli abnormality (emphysema)
• Airflow obstruction that's persistent and progressive

However, airflow obstruction is mandatory for diagnosis of COPD. GOLD currently diagnoses COPD as spirometry measurement of not fully reversible airflow obstruction: FEV1/FVC < 0.7 post bronchodilation.¹ ATS, on the other hand, tends to use LLN for diagnosis of airflow obstruction.² Use of fixed ratio can cause over diagnosis of COPD in elderly and under diagnosis in young people.

Patients with symptoms or image findings but without obstruction are known as Pre-COPD or PRISm (preserved ratio impaired spirometry). They are at risk of developing obstruction over time.

This distinction is important because there is no benefit of bronchodilators in smokers without PFT changes.³

Links to this note

• COPD chronic obstructive pulmonary disease
  • diagnosis of COPD must have airflow obstruction
• COPD 2023 GOLD Report
  • diagnosis of COPD must have airflow obstruction

Footnotes

1. https://goldcopd.org/2023-gold-report-2/ ↩

2. https://www.atsjournals.org/doi/full/10.1513/AnnalsATS.201709-733ED ↩

3. https://www.nejm.org/doi/full/10.1056/NEJMoa2204752 ↩