Table 3 –

Odds of mortality according to hospital volume

	Model 1 OR [95% CI]	Model 2 OR [95% CI]	Model 3 OR [95% CI]	Model 4 OR [95% CI]
Low-volume hospital	4.0 [2.7–5.8]	3.4 [2.3–5.0]	3.4 [2.2–5.2]	2.2 [1.3–3.7]
Medium-volume hospital	2.0 [1.3–3.0]	1.9 [1.2–2.8]	1.9 [1.2–2.9]	1.6 [1.0–2.5]
High-volume hospital	Ref	Ref	Ref	Ref

OR = odds ratio; CI = confidence interval

Model 1 = hospital volume alone

Model 2 = Model 1 + patient characteristics

Model 3 = Model 2 + number of hospital beds

Model 4 = Model 3 + systems characteristics

Patient characteristics = gender + age + race + admission type + Charlson score ≥3

Systems characteristics = high nurse ratio + complex medical oncology services + lung transplantation services + bariatric surgery services + PET scanner

PET = positron emission tomography