Table 4.

Results of extreme value imputation for assessing associations of adverse neonatal outcomes with cystic fibrosis in a cohort of infants born in Washington State in the years 1996-2013.

	1996-2013		2006-2013
	RR* (95% CI)	Imputed RR* (95% CI)1	RR* (95% CI)	Imputed RR* (95% CI)2
LBW	3.2 (2.3-4.5)	2.3 (1.6-3.1)	3.7 (2.3-5.8)	2.4 (1.5-3.7)
SGA	1.6 (1.1-2.3)	1.3 (1.0-1.9)	0.9 (0.4-2.2)	1.0 (0.6-1.8)
Pre-term Birth	2.8 (2.1-3.8)	2.1 (1.6-2.7)	2.7 (1.8-4.1)	1.8 (1.3-2.7)
Infant Death	5.5 (1.5-19.4)	3.2 (0.9-11.3)	12.0 (2.9-49.2)	6.0 (1.4-24.7)

^*RR (relative risk) presented are unadjusted for confounding by maternal race yet are similar to the adjusted estimates shown in Table 3.

¹The prevalence of LBW, SGA, pre-term birth, and infant death in infants without CF, born in 1996-2013, was 5.9%, 8.4%, 8.5%, and 0.3%, respectively. We applied these prevalence estimates to the 123 infants with CF expected to have been missed through the study's ascertainment method in the 1996-2013 birth cohort.

²The prevalence of LBW, SGA, pre-term birth, and infant death in infants without CF born in 2006-2013, was 6.8%, 8.0%, 10.3%, and 0.4%, respectively). We applied these prevalence estimates to the 69 infants with CF expected to have been missed through the study's ascertainment method in the 2006-2013 cohort.

RR=risk ratio, LBW=low birth weight, SGA=small for gestational age, CF=cystic fibrosis