Table 4– Relative rates of death, asthma death and hospitalisation for status asthmaticus during current exposure, stratified by exposure characteristics and statistical comparisons of each exposure characteristics between combinations of asthma medications

Duration since first Rx and number of prior Rx in previous yr^#	LABA with ICS^¶	LABA without ICS^¶	LABA with SABA^¶	LABA without SABA^¶	SABA with other asthma drugs (without ICS or LABA)^¶	SABA with ICS (without LABA)^¶	ICS (without SABA or LABA)^¶
Death
<3 months	2.1 (1.7–2.6)	2.4 (1.6–3.5)	1.9 (1.5–2.5)	2.7 (2.0–3.7)	3.1 (2.8–3.5)⁺	2.8 (2.3–3.3)^§	2.0 (1.5–2.8)
3–12 months	1.5 (1.2–1.8)	1.3 (0.9–1.9)	1.4 (1.1–1.7)	1.4 (1.0–2.0)	1.9 (1.7–2.1)	1.8 (1.5–2.2)^§	1.4 (1.0–1.8)
≥1 yr
<3 Rx	Reference	Reference	Reference	Reference	Reference	Reference	Reference
3–6 Rx	0.9 (0.7–1.1)	0.8 (0.6–1.3)	0.8 (0.6–1.0)	1.0 (0.7–1.3)	0.9 (0.8–1.1)	0.9 (0.8–1.1)	1.0 (0.9–1.3)
7–12 Rx	1.0 (0.8–1.2)	1.0 (0.7–1.5)	0.9 (0.7–1.1)	1.1 (0.8–1.5)	1.0 (0.9–1.1)	1.1 (0.9–1.3)	1.4 (1.1–1.6)^ƒ
≥13 Rx	1.5 (1.2–1.9)	1.5 (0.9–2.7)	1.2 (0.9–1.6)	1.6 (1.1–2.5)	1.3 (1.1–1.5)	1.5 (1.3–1.7)	1.9 (1.4–2.7)
Asthma death
<3 months	1.3 (0.6–3.2)		1.1 (0.3–3.6)		0.7 (0.3–1.8)	3.9 (1.3–11.6)
3–12 months	1.0 (0.4–2.4)		1.4 (0.5–3.9		1.5 (0.6–3.6)	0.9 (0.2–3.8)
≥1 yr
<3 Rx	Reference		Reference		Reference	Reference
3–6 Rx	0.7 (0.3–1.6)		0.7 (0.3–2.1)		0.6 (0.3–1.4)	1.3 (0.5–3.6)
7–12 Rx	1.0 (0.4–2.1)		1.1 (0.4–3.0)		1.3 (0.6–2.6)	1.3 (0.5–3.3)
≥13 Rx	1.4 (0.5–3.7)		1.4 (0.4–4.7)		1.6 (0.7–3.7)	2.4 (0.9–5.9)
Hospitalisation (HES)
<3 months	0.9 (0.4–2.0)	0.7 (0.2–2.5)	0.8 (0.3–1.9)	0.9 (0.2–3.7)
3–12 months	0.9 (0.4–2.0)	0.6 (0.1–2.2)	0.9 (0.4–1.9)	0.7 (0.2–2.9)
≥1 yr
<3 Rx	Reference	Reference	Reference	Reference
3–6 Rx	0.7 (0.3–1.4)	0.2 (0.03–0.8)	0.3 (0.2–0.7)	0.6 (0.2–2.0)
7–12 Rx	0.8 (0.4–1.6)	0.2 (0.02–1.2)	0.5 (0.2–1.0)	0.4 (0.1–1.6)
≥13 Rx	0.9 (0.3–2.8)	0.9 (0.1–7.5)	0.7 (0.2–2.3)
GP visit for exacerbation
<3 months	0.7 (0.7–0.8)	0.8 (0.7–1.0)	0.9 (0.8–1.0)	0.9 (0.8–1.0)	0.7 (0.6–0.8)⁺	1.0 (0.9–1.1)^§	0.8 (0.6–0.9)
3–12 months	0.9 (0.9–1.0)	0.9 (0.8–1.1)	1.0 (0.9–1.1)	0.9 (0.8–1.0)	1.1 (0.9–1.4)	1.2 (1.1–1.3)^§	0.8 (0.7–0.9)^ƒ
≥1 yr
<3 Rx	Reference	Reference	Reference	Reference	Reference	Reference	Reference
3–6 Rx	1.1 (1.0–1.1)^##	0.9 (0.8–1.0)^##	1.0 (1.0–1.1)	1.0 (0.9–1.1)	1.4 (1.3–1.6)⁺	1.2 (1.1–1.3)^§	1.0 (0.9–1.1)
7–12 Rx	1.2 (1.1–1.3)^##	0.9 (0.8–1.0)^##	1.2 (1.1–1.3)	1.1 (1.0–1.3)	1.9 (1.7–2.1)⁺	1.3 (1.2–1.4)^§	1.2 (1.1–1.3)
≥13 Rx	1.5 (1.4–1.6)^##	1.0 (0.8–1.4)^##	1.4 (1.3–1.5)	1.5 (1.3–1.8)	2.9 (2.5–3.3)⁺	1.6 (1.5–1.7)^§	1.7 (1.4–2.2)^ƒ

Data are presented as RR (95% CI), adjusted for age, sex, calendar year and comedication; no RRs could be estimated with small number of cases. Rx: prescription; LABA: long-acting β₂-agonist; ICS: inhaled corticosteroid; SABA: short-acting β₂-agonist; HES: hospital episode statistics; GP: general practioner. ^#: The classification of exposure characteristics was based on the main drug of interest in each column. ^¶: “With” indicates concomitant prescribing (i.e. prescribing of both medications at the same date); “without” indicates no concomitant prescribing (i.e. no prescribing of the other medication at the same date or in the three months before). ⁺: p<0.05 for each exposure characteristic of RR interaction between LABA and SABA with other asthma drugs but without ICS and LABA. ^§: p<0.05 for each exposure characteristic of RR interaction between LABA and SABA with ICS but without LABA. ^ƒ: p<0.05 for each exposure characteristic of RR interaction between LABA and ICS without SABA or LABA. ^##: p<0.05 for each exposure characteristic of RR interaction between LABA with ICS and LABA without ICS.