Table 2.

Stratified adjusted models (< 1 year old and ≥ 1 year old) showing incidence rate ratios for the three service types, comparing the false positive cohort with the primary (unmatched) comparison cohort

	Adjusted incidence rate ratio (95 % CI)
	< 1 year of age			≥ 1 year of age
	Physician visits	ED visits	Hospitalizations	Physician visits	ED visits	Hospitalizations
False Positive	1.42 (1.21–1.67)	1.27 (0.80–2.03)	2.32 (1.22–4.34)	0.96 (0.77–1.20)	0.82 (0.54–1.26)	0.68 (0.15–2.25)
Sex
Female	0.92 (0.91–0.92)	0.85 (0.85–0.86)	0.76 (0.75–0.77)	0.91 (0.91–0.92)	0.86 (0.85–0.87)	0.78 (0.77–0.80)
Male	Reference	Reference	Reference	Reference	Reference	Reference
Season of birth
Jan.–Apr.	Reference	Reference	Reference	Reference	Reference	Reference
May–Aug.	1.01 (1.00–1.01)	1.04 (1.03–1.05)	0.98 (0.96–1.00)	0.96 (0.95–0.96)	0.95 (0.95–0.96)	0.94 (0.92–0.97)
Sept.–Dec.	1.00 (1.00–1.01)	1.02 (1.00–1.03)	1.08 (1.06–1.11)	1.00 (0.99–1.00)	1.00 (0.99–1.00)	1.03 (1.00–1.05)
Birth weight
< 2500 g	1.75 (1.74–1.77)	1.04 (1.01–1.06)	2.14 (2.08–2.21)	1.13 (1.12–1.14)	1.03 (1.01–1.05)	1.59 (1.51–1.66)
≥ 2500 g	Reference	Reference	Reference	Reference	Reference	Reference
Gestational age
< 37 weeks	1.57 (1.56–1.58)	1.23 (1.21–1.26)	2.65 (2.57–2.73)	1.09 (1.09–1.10)	1.17 (1.15–1.19)	1.42 (1.36–1.48)
≥ 37 weeks	Reference	Reference	Reference	Reference	Reference	Reference
Socioeconomic status
‘Lower’	1.00 (1.00–1.00)	1.23 (1.22–1.24)	1.09 (1.07–1.11)	0.96 (0.96–0.97)	1.12 (1.11–1.13)	1.10 (1.08–1.13)
‘Higher’	Reference	Reference	Reference	Reference	Reference	Reference
Urban-rural status
Rural	0.79 (0.78–0.79)	2.34 (2.30–2.37)	1.16 (1.13–1.20)	0.73 (0.72–0.73)	2.28 (2.25–2.31)	1.15 (1.11–1.20)
Urban	Reference	Reference	Reference	Reference	Reference	Reference