Introduction

Chronic obstructive pulmonary disease (COPD) is one of the most common diagnoses encountered in medical practice. COPD is an umbrella term encompassing the older terms chronic bronchitis and emphysema. In the vast majority of cases, COPD is caused by smoking. Some patients with more mild disease may just need to use a bronchodilator occasionally whereas other patients may have several hospital admissions a year secondary to infective exacerbations.

Epidemiology

  • Incidence: 230.00 cases per 100,000 person-years
  • Peak incidence: 60-70 years
  • Sex ratio: more common in males 1.1:1
Condition Relative
incidence
Chronic obstructive pulmonary disease1
Bronchiectasis0.07
Extrinsic allergic alveolitis0.004
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Aetiology

Smoking accounts for the vast majority of cases.

Alpha-1 antitrypsin deficiency

Other causes
  • cadmium (used in smelting)
  • coal
  • cotton
  • cement
  • grain

Clinical features

Features
  • cough: often productive
  • dyspnoea
  • wheeze
  • in severe cases, right-sided heart failure may develop resulting in peripheral oedema

Diagnosis

NICE recommend considering a diagnosis of COPD in patients over 35 years of age who are smokers or ex-smokers and have symptoms such as exertional breathlessness, chronic cough or regular sputum production.

The following investigations are recommended in patients with suspected COPD:
  • post-bronchodilator spirometry to demonstrate airflow obstruction: FEV1/FVC ratio less than 70%
  • chest x-ray: hyperinflation, bullae, flat hemidiaphragm. Also important to exclude lung cancer
  • full blood count: exclude secondary polycythaemia
  • body mass index (BMI) calculation

The severity of COPD is categorised using the FEV1*:

Post-bronchodilator FEV1/FVCFEV1 (of predicted)Severity
< 0.7> 80%Stage 1 - Mild**
< 0.750-79%Stage 2 - Moderate
< 0.730-49%Stage 3 - Severe
< 0.7< 30%Stage 4 - Very severe

Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of airflow obstruction.

*note that the grading system has changed following the 2010 NICE guidelines. If the FEV1 is greater than 80% predicted but the post-bronchodilator FEV1/FVC is < 0.7 then this is classified as Stage 1 - mild

**symptoms should be present to diagnose COPD in these patients

Management

NICE updated its guidelines on the management of chronic obstructive pulmonary disease (COPD) in 2018.

General management
  • >smoking cessation advice: including offering nicotine replacement therapy, varenicline or bupropion
  • annual influenza vaccination
  • one-off pneumococcal vaccination
  • pulmonary rehabilitation to all people who view themselves as functionally disabled by COPD (usually Medical Research Council [MRC] grade 3 and above)

Bronchodilator therapy
  • a short-acting beta2-agonist (SABA) or short-acting muscarinic antagonist (SAMA) is first-line treatment
  • for patients who remain breathless or have exacerbations despite using short-acting bronchodilators the next step is determined by whether the patient has 'asthmatic features/features suggesting steroid responsiveness'

There are a number of criteria NICE suggest to determine whether a patient has asthmatic/steroid responsive features:
  • any previous, secure diagnosis of asthma or of atopy
  • a higher blood eosinophil count - note that NICE recommend a full blood count for all patients as part of the work-up
  • substantial variation in FEV1 over time (at least 400 ml)
  • substantial diurnal variation in peak expiratory flow (at least 20%)

Interestingly NICE do not recommend formal reversibility testing as one of the criteria. In the guidelines they state that 'routine spirometric reversibility testing is not necessary as part of the diagnostic process or to plan initial therapy with bronchodilators or corticosteroids. It may be unhelpful or misleading...'. They then go on to discuss why they have reached this conclusion. Please see the guidelines for more details.

No asthmatic features/features suggesting steroid responsiveness
  • add a long-acting beta2-agonist (LABA) + long-acting muscarinic antagonist (LAMA)

Asthmatic features/features suggesting steroid responsiveness
  • LABA + inhaled corticosteroid (ICS)
  • if patients remain breathless or have exacerbations offer triple therapy i.e. LAMA + LABA + ICS
  • NICE recommend the use of combined inhalers where possible


Oral theophylline
  • NICE only recommends theophylline after trials of short and long-acting bronchodilators or to people who cannot used inhaled therapy
  • the dose should be reduced if macrolide or fluoroquinolone antibiotics are co-prescribed

Oral prophylactic antibiotic therapy
  • azithromycin prophylaxis is recommended in select patients
  • patients should not smoke, have optimised standard treatments and continue to have exacerbations
  • other prerequisites include a CT thorax (to exclude bronchiectasis) and sputum culture (to exclude atypical infections and tuberculosis)
  • LFTs and an ECG to exclude QT prolongation should also be done as azithromycin can prolong the QT interval

Mucolytics
  • should be 'considered' in patients with a chronic productive cough and continued if symptoms improve

Cor pulmonale
  • features include peripheral oedema, raised jugular venous pressure, systolic parasternal heave, loud P2
  • use a loop diuretic for oedema, consider long-term oxygen therapy
  • ACE-inhibitors, calcium channel blockers and alpha blockers are not recommended by NICE

Factors which may improve survival in patients with stable COPD
  • smoking cessation - the single most important intervention in patients who are still smoking
  • long term oxygen therapy in patients who fit criteria
  • lung volume reduction surgery in selected patients

Long-term oxygen therapy

The 2018 NICE guidelines on COPD clearly define which patients should be assessed for and offered long-term oxygen therapy (LTOT). Patients who receive LTOT should breathe supplementary oxygen for at least 15 hours a day. Oxygen concentrators are used to provide a fixed supply for LTOT.

Assess patients if any of the following:
  • very severe airflow obstruction (FEV1 < 30% predicted). Assessment should be 'considered' for patients with severe airflow obstruction (FEV1 30-49% predicted)
  • cyanosis
  • polycythaemia
  • peripheral oedema
  • raised jugular venous pressure
  • oxygen saturations less than or equal to 92% on room air

Assessment is done by measuring arterial blood gases on 2 occasions at least 3 weeks apart in patients with stable COPD on optimal management.

Offer LTOT to patients with a pO2 of < 7.3 kPa or to those with a pO2 of 7.3 - 8 kPa and one of the following:
  • secondary polycythaemia
  • peripheral oedema
  • pulmonary hypertension

In terms of smoking, NICE advise the following:
  • do not offer LTOT to people who continue to smoke despite being offered smoking cessation advice and treatment, and referral to specialist stop smoking services.

NICE suggest that a structured risk assessment is carried out before offering LTOT, including:
  • the risks of falls from tripping over the equipment
  • the risks of burns and fires, and the increased risk of these for people who live in homes where someone smokes (including e‑cigarettes)