COPD vs Asthma
| COPD | Asthma | |
| Smoker | Almost all | Maybe |
| <35y | Rare | Often |
| Chronic productive cough | Common | Rare |
| Breathless | Persistent and progressive | Variable |
| Night time breathlessness or wheeze | Rare | Common |
| Day to day variation | Rare | Common |
| If any doubt, consider reversibility testing. | ||
Spirometry
Restrictive pattern
- Examples – fibrosing alveolitis, scoliosis
- FVC < 80%
- FEV1 reduced
- FEV1/FVC normal
Obstructive pattern
- COPD
- FEV1/FVC < 0.7
- FEV1 < 80%
- Mild 50-80%
- Moderate 30-49%
- Severe < 30%
- Reversibility test only if diagnostic doubt or asthma co-existing
- COPD excluded if
- FEV1/FVC & FEV1 returns normal after bronchodilator
- Consider asthma if
- Large (>400ml) FEV1 response to bronchodilator
- COPD excluded if
- Asthma
- High probability – Treatment and review
- Intermediate – Reversibility spirometry
- FEV1/FVC < 0.7
- FEV1 < 80%
- Large (>400ml) FEV1 response to bronchodilator
- Low probability – Consider alternative diagnosis [reconsider diagnosis if other causes excluded]
- PEFR logs
- >60 l/min is significant reversibility
- Look for daily or diurnal variations
- > 20% variation is of significance