Table 1.

Differences between asthma and COPD

FACTORSASTHMACOPD
Influence of smoking on disease process
  • no direct relationship but can adversely influence disease control

  • some asthma cases can develop into COPD after many years of smoking

  • direct relationship

Inflammation (airways)
  • eosinophilic

  • neutrophilic

Reversibility of airway obstruction
  • hallmark of asthma

  • airway obstruction is episodic and completely reversible in mild disease

  • in chronic severe disease, only partial reversibility seen with either bronchodilator or anti-inflammatory therapy

  • airway obstruction is persistent with little or no response to bronchodilator or anti-inflammatory therapy in most patients

Age
  • onset often in early life: asthma is the most common chronic disease in children

  • onset in later life; often in sixth decade

Course with time
  • episodic

  • slow, insidious decline in lung function leading to disability

Role of atopy
  • most asthma patients are allergic to airborne allergens such as dust mite, animal dander, pollens, molds

  • uncommon

Symptoms
  • episodic

  • slowly progressive

Signs (other)
  • cor pulmonale never seen

  • cor pulmonale when disease is severe

Diffusing capacity
  • normal in pure asthma

  • often decreased; more so with emphysema

Hypoxemia
  • not common but can be present in severe exacerbations

  • often present and chronic in advanced disease

Bronchodilator response
  • often marked improvements in FEV1 into the normal range

  • can be present, but FEV1 typically remains chronically reduced

Response to corticosteroids
  • often dramatic

  • most patients do not respond in a clinically meaningful way

Chest x-ray scan
  • often normal or findings of hyperinflation, which are episodic

  • can be normal

  • increased bronchial markings

  • chronic hyperinflation (emphysema)

  • useful to rule out other conditions

  • COPD—chronic obstructive pulmonary disease, FEV1—maximal volume of air exhaled after a maximal inhalation in the first second of a forced exhalation.

  • Reprinted with permission from D’Urzo.6