Table 6 Variables used to generate the propensity score

Age (years)

Sex

Smoking status

Body mass index (kg/m²)

Cardiovascular disease diagnosis

Ischemic heart disease diagnosis

Hypertension diagnosis

Components of the Charlson comorbidity index, diagnoses of:

 Myocardial infarction

 Stroke

 Heart failure

 Connective tissue disorders

 Dementia

 Diabetes

 Mild liver disease

 Peptic ulcer

 Peripheral vascular disease

 Pulmonary disease

 Cancer

 Paraplegia

Other chronic respiratory diseases

Number of prescriptions (categorized):

 Nasal corticosteroids

 Antibiotics prescribed on the same day as a lower respiratory consultation (identified by a Read code for a lower respiratory event)

 Acute oral corticosteroids (OCS)

 All OCS

 Short-acting muscarinic antagonists (SAMA)

Medication ≥ 1 prescriptions (yes/no):

 Maintenance OCS

 Long-acting β-agonists (LABA)

 Long-acting muscarinic antagonists (LAMA)

 Methylxanthines

 Leukotriene receptor antagonists

Short-acting β-agonists (SABA), mean daily dose (salbutamol equivalents), categorized

Number of (categorized):

 Exacerbations (moderate/severe)

 Emergency department respiratory attendances

 Inpatient respiratory admissions

 Outpatient respiratory visits