Table 2.

Odds of Antibiotic Prescription for URTI per Visit After 2 Years of Age, Given Antibiotics Prescribed for URTI prior to 2 Years of Age

	Unadjusted OR (95% CI)	P	Adjusted OR (95% CI)a	P
Antibiotic prescription for URTI prior to 2years of age	1.59 (1.38 to 1.83)	<.001***	1.39 (1.19 to 1.63)	<.001***
Antibiotic prescription for AOM URTI prior to 2 years of ageb	1.59 (1.11 to 2.28)	.01**	1.44 (1.00 to 2.05)	.05*

Abbreviations: OR, odds ratio; CI, confidence interval; zBMI, standardized body mass index; GEE, Generalized Estimating Equation; URTI, upper respiratory tract infection; AOM, acute otitis media.

^aEstimated based on GEE model adjusted for observation time, gender, zBMI, maternal age, maternal education level, number of URTI visits from birth to 2 years of age, median household income based on postal code, number of siblings, whether or not the child was registered in a licensed daycare (Y/N), ethnicity, and site. Covariates with missing data were imputed using the multiple imputation by chained equations (MICE) method.

^bInteraction P value for adjusted model = .27.

*P ≤ .05, **P ≤ .01, ***P ≤ .001.