Table 1.

Baseline characteristics of the sample

Variable	Value
Total sample	21,144
Female; N (%)	11,722 (55.4%)
Age at index date; Mean (SD)	28.7 (9.4)
Socio-economic status; N (%)
Quintile 1	4624 (21.9%)
Quintile 2	4030 (19.1%)
Quintile 3	4077 (19.3%)
Quintile 4	4073 (19.2%)
Quintile 5	3916 (18.5%)
Unknown	424 (2%)
Variables estimated during follow-up
Patient years with severe asthma	40,803
Patient years associated with maintenance OCS use	3348 (8.2%)
Episodic OCS use; mean number of episodes (SD)	0.89 (0.79)
Patient-years with at least one episodic use of OCS; N (%)	30,684 (75%)
Patient-years with asthma-related hospital admission; N (%)	1502 (3.7%)
Patient-years with asthma-related physician visits; N (%)
GP visits	25,425 (62.3%)
Respirologist	1983 (4.9%)
General internist	1012 (2.5%)
SABA canisters used per patient-year, Mean (SD)	6.2 (5.4)
Medication Possession Ratio for ICS per patient-year; mean (SD)	26.7% (29.4%)
Comorbidity: N(%)
Group 1 (Myocardial infarction)	90 (0.2%)
Group 2 (Congestive heart failure)	369 (0.9%)
Group 3 (Peripheral vascular disease)	169 (0.4%)
Group 4 (Cerebrovascular disease)	173 (0.4%)
Group 5 (Dementia)	84 (0.2%)
Group 6 (Chronic pulmonary disease)	7818 (19.2%)
Group 7 (Connective tissue disease)	641 (1.6%)
Group 8 (Peptic ulcer disease)	308 (0.8%)
Group 9 (Mild liver disease)	581 (1.4%)
Group 10 (Diabetes without complication)	2105 (5.2%)
Group 11 (Diabetes with complication)	130 (0.3%)
Group 12 (Paraplegia and Hemiplegia)	81 (0.2%)
Group 13 (Renal disease)	276 (0.7%)
Group 14 (Cancer)	435 (1.1%)
Group 15 (Moderate or Severe liver Disease)	67 (0.2%)
Group 16 (Metastatic Carcinoma)	78 (0.2%)
Group 17 (AIDS/HIV)	162 (0.4%)

OCS oral corticosteroid, ICS inhaled corticosteroids, SABA short-acting beta agonists, SD standard deviation