COPD and Asthma: How to Tell Them Apart, Reading Your Spirometry, Why Inhalers "Don't Work", and an Action Plan for Flare-ups

How COPD and asthma differ

Both are chronic airway diseases causing breathlessness, cough, sputum and wheeze, but they are fundamentally different [1][2]:

Some people have both (formerly "ACO"); treatment then follows asthma principles and must include an inhaled corticosteroid [1][2].

Reading your lung-function report

Spirometry is required for diagnosis [1][2]:

• FVC (forced vital capacity): total air exhaled after a full breath in.
• FEV₁: the amount exhaled in the first second.
• FEV₁/FVC: post-bronchodilator <0.70 = airflow obstruction (the COPD criterion; the fixed ratio can over-diagnose in older people, a limitation GOLD acknowledges).
• FEV₁ % predicted: grades COPD severity — GOLD 1 ≥80%, GOLD 2 50–79%, GOLD 3 30–49%, GOLD 4 <30% [1].

COPD treatment is not chosen on FEV₁ alone: GOLD 2025 uses symptoms (mMRC or CAT questionnaire) plus exacerbations in the past year to assign groups A, B and E [1].

For kidney patients: uraemia and fluid overload also cause breathlessness; in dialysis, breathlessness is not necessarily pulmonary. Perform spirometry at dry weight.

Inhalers: the classes, and why they "don't work"

Drug classes

The big change in asthma (GINA since 2019): SABA-only treatment is no longer recommended — it increases severe exacerbations and death. Even in mild asthma, GINA's preferred option is as-needed ICS-formoterol (relieves and treats inflammation) [2].

COPD [1]: group A a single bronchodilator; groups B and E LABA+LAMA; add ICS (triple therapy) in group E if blood eosinophils ≥300 cells/µL. ICS increases pneumonia risk in COPD and is not for everyone.

Why inhalers "don't work"

Studies show 70–90% of patients make inhaler errors [2]. Common ones:

1. Metered-dose inhaler (MDI): actuation not coordinated with inhalation; inhaling too fast; not holding the breath 5–10 s. A spacer greatly improves delivery.
2. Dry-powder inhaler (DPI): inhaling too weakly or shallowly; exhaling into the device (moisture).
3. Not rinsing the mouth after ICS → oral thrush, hoarse voice.
4. Stopping maintenance therapy once symptoms settle.

Ask your clinician to watch you use the inhaler at every visit.

Non-drug treatment: some things beat medication

• Smoking cessation: the only intervention that slows the decline in lung function in COPD; beneficial at any age [1]. Pharmacotherapy (varenicline, nicotine replacement, bupropion) plus counselling doubles success.
• Pulmonary rehabilitation: exercise training plus education improves breathlessness, exercise capacity and quality of life and reduces readmission after exacerbations; GOLD's highest grade of evidence [1][5].
• Vaccines: influenza (yearly), pneumococcal (PCV20 or PCV15+PPSV23), COVID-19, RSV (≥60), Tdap, zoster [1].
• Avoid triggers: air pollution (limit outdoor activity and wear a mask on high-PM2.5 days), allergens, occupational exposures.
• Oxygen: long-term oxygen prolongs life only in COPD with severe resting hypoxaemia (PaO₂ ≤55 mmHg); there is no survival benefit in mild–moderate hypoxaemia [1].

Flare-ups: the action plan

Definition of an exacerbation: symptoms (breathlessness, cough, sputum volume or colour) clearly beyond day-to-day variation within 14 days [1].

Asthma action plan (GINA zones) [2]:

• 🟢 Green (well controlled): continue maintenance.
• 🟡 Yellow (more symptoms, night waking, more reliever use, peak flow 60–80% of personal best): step up ICS-formoterol or ICS as planned; no improvement in 48 h → see a doctor.
• 🔴 Red (can't speak in full sentences, blue lips, reliever not working, peak flow <60%): seek emergency care now, using the reliever on the way.

COPD exacerbation [1]: increase short-acting bronchodilator; most moderate–severe exacerbations need 5 days of oral steroid (prednisolone 40 mg); add antibiotics for 5–7 days if sputum becomes purulent, increases, or hospitalisation is needed. After an exacerbation, reassess maintenance therapy and arrange rehabilitation.

Medication notes for kidney patients and transplant recipients

• Oral steroids raise glucose and blood pressure; transplant recipients already on steroids should tell their transplant team about extra courses.
• Theophylline has a narrow therapeutic window, hepatic metabolism and many interactions; GOLD no longer recommends routine use.
• Antibiotics (levofloxacin, azithromycin) need dose adjustment in CKD; azithromycin with tacrolimus may prolong the QT interval.
• Inhalers are kidney-safe, but antimuscarinic inhalers can worsen urinary retention in men with prostate enlargement.
• Pneumococcal and influenza vaccination is especially important in dialysis (pneumonia is a leading infectious cause of death).

When to seek care immediately

Call emergency services: severe breathlessness at rest, unable to finish a sentence, blue lips or nails, confusion or drowsiness, reliever ineffective after 2–3 uses, chest pain.

Same day: fever with purulent sputum, blood in sputum, worsening leg swelling, needing to sit up to breathe at night, peak flow persistently <80%.

Questions to ask your doctor

1. What are my FEV₁/FVC and FEV₁ %? Do I have COPD, asthma or both?
2. Is my inhaler technique correct — can I show you? Do I need a spacer?
3. Do I have a written action plan? How do I adjust in the yellow zone?
4. Can I join pulmonary rehabilitation?
5. Which vaccines do I need, and am I up to date this year?

References

1. Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management, and Prevention of COPD: 2025 Report. https://goldcopd.org/2025-gold-report/
2. Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention, 2024. https://ginasthma.org/2024-report/
3. GBD 2021 Causes of Death Collaborators. Lancet. 2024;403(10440):2100–2132. https://doi.org/10.1016/S0140-6736(24)00367-2
4. World Health Organization. COPD fact sheet. 2024. https://www.who.int/news-room/fact-sheets/detail/chronic-obstructive-pulmonary-disease-(copd)
5. McCarthy B, et al. Pulmonary rehabilitation for COPD. Cochrane Database Syst Rev. 2015;(2):CD003793. https://doi.org/10.1002/14651858.CD003793.pub3

This article compiles publicly available medical information for educational purposes only. It is not medical advice and has not been reviewed by a practising physician. For any health or medication question, consult a qualified professional. For chest pain, sudden breathlessness, one-sided weakness or slurred speech, call your local emergency number or go to the emergency department immediately.