. Author manuscript; available in PMC: 2009 Feb 24.

Published in final edited form as: Ann Allergy Asthma Immunol. 2008 Nov;101(5):482–487. doi: 10.1016/S1081-1206(10)60286-4

Table 2.

Relationship Between the Frequency of Short-Acting β-Agonist Use Via Metered-Dose Inhaler and/or Nebulizer and Asthma-Related Outcomes

Exposure variable(s)	Outcome variable
	Oral corticosteroid use	Asthma-related emergency department visit	Asthma-related hospitalization
	aHR (95% CI)^a	aHR (95% CI)^a	aHR (95% CI)^a
Current short-acting β-agonist nebulizer use per day	1.37 (0.63–2.97)	6.32 (2.38–16.80)^e	21.62 (3.17–147.57)^d
Current short-acting β-agonist metered-dose inhaler use per day	1.04 (0.99–1.09)	1.05 (0.97–1.14)	1.17 (0.98–1.40)
Oral corticosteroid fill in the year preceding index date	1.19 (1.13–1.25)^e	1.02 (0.88–1.19)	1.21 (0.96–1.52)
Asthma-related emergency department visits in the year preceding index date	1.07 (0.96–1.19)	1.53 (1.32–1.78)^e	1.49 (1.08–2.05)^c
Asthma-related hospitalizations in the year preceding index date	1.04 (0.73–1.47)	1.20 (0.71–2.03)	1.61 (0.57–4.58)
Historic short-acting β-agonist nebulizer use per day^b	1.22 (1.10–1.35)^e	1.12 (0.92–1.37)	1.21 (0.72–2.03)
Historic short-acting β-agonist metered-dose inhaler use per day^b	1.06 (0.99–1.13)	1.21 (1.04–1.40)^c	0.91 (0.67–1.25)

Abbreviations: aHR, adjusted hazard ratio; CI, confidence interval.

Relationship between current short-acting metered-dose inhaler use and/or nebulizer use and outcome, adjusting for the following in the year before the index date: oral steroid use, asthma-related emergency department visits, asthma-related hospitalizations, historic short-acting metered-dose inhaler use, and historic short-acting nebulizer use. The model also adjusts for patient age, sex, and race-ethnicity. Because this population was drawn from a larger study of inhaled corticosteroid use, the index date was defined as the first electronic prescription for an inhaled corticosteroid between January 1, 2005, and December 31, 2006. Current short-acting β-agonist use is defined as the calculated number of uses per day in the 3 months preceding the outcome; therefore, the hazard ratio for these variables represents the increased risk associated with one more use (ie, puff or nebulizer dose) per day.

Variables are natural log-transformed.

P <.05.

P <.01.

P <.001.