Table 4.

Results of regression analyses of intensive care unit and hospital lengths of stay for patients with interstitial lung disease or chronic obstructive pulmonary disease, compared with patients with cancer (reference group)

	ILD			COPD		P Value*
	β Value	95% CI	P Value*	β Value	95% CI
ICU days†	2.75	0.52–4.98	0.016	2.93	0.77–5.09	0.008
Hospital days‡	2.40	−0.32 to 5.11	0.084	2.55	0.19–4.92	0.034

Definition of abbreviations: CI = confidence interval; COPD = chronic obstructive pulmonary disease; ILD = interstitial lung disease; ICU = intensive care unit.

Lengths of stay for the two chronic lung diseases were tested using robust linear regression models with cancer as the reference group. All models were adjusted for potential confounders of the association between diagnosis and outcome. To qualify as a confounder, the estimated coefficient for diagnosis was found to have changed by at least 10% from the base model containing only the diagnosis, with the addition of one of the following confounders: patient age, sex, minority status, marital status, education level, hospital, and the hospital’s intervention status at the time the patient received care.

^*Bold values indicate significance at P = 0.05.

Symbols in left column indicate final models adjusted for ^†age, minority status, and hospital and ^‡age, sex, minority status, hospital, and marital status.