Table 3.

Adjusted Odds of In-Hospital Mortality by Age Group and Annual ECMO Volume Category

		Adjusted Mortality Odds Ratio (95% CI)
Period	Annual Hospital ECMO Volume	Neonate	Pediatric	Adult
1989–2013	1–5	Referent	Referent	Referent
	6–14	0.86 (0.75–0.98)	0.99 (0.86–1.13)	0.81 (0.66–0.995)
	15–30	0.74 (0.63–0.88)	0.86 (0.73–1.01)	0.75 (0.59–0.94)
	>30	0.69 (0.56–0.84)	0.89 (0.69–1.14)	0.61 (0.48–0.79)
2008–2013	1–5	Referent	Referent	Referent
	6–14	1.01 (0.79–1.28)	1.03 (0.84–1.25)	0.82 (0.64–1.05)
	15–30	0.94 (0.70–1.25)	0.92 (0.73–1.16)	0.72 (0.55–0.96)
	>30	0.65 (0.42–1.01)	0.85 (0.57–1.28)	0.61 (0.46–0.80)

Definition of abbreviations: CI = confidence interval; ECMO = extracorporeal membrane oxygenation.

The adjusted odds ratio reflects findings from models that included hospital- and patient-level demographic and pre-ECMO clinical variables (see Methods); all analyses were performed with a hierarchical logistic regression model to account for patient-level and hospital-level variance.