Table 4. Sensitivity analysis (excluding patients with a previous history of anaphylaxis).

Characteristics		OR (95% CI)	P value	P trend
Age (yr)
	< 7	0.33 (0.15–0.66)	0.003	< 0.001
	7–12	0.57 (0.29–1.05)	0.085
	13–18	0.70 (0.39–1.21)	0.215
	19–65 (reference)	1.00 (reference)
	> 65	1.29 (0.95–1.74)	0.096
Past history
	Anaphylaxis	Excluded from sensitivity analysis
	Cardiovascular disease	0.92 (0.74–1.15)	0.463
Miscellaneous
	City dweller	1.07 (0.81–1.43)	0.638
	Upper income class	0.90 (0.74–1.11)	0.330
	Larger hospital (300 or more)	1.01 (0.81–1.26)	0.907

OR, odds ratio; CI, confidence interval.