Table 4. Adjusted hospital cost ratios after subarachnoid hemorrhage.

Variables	Adjusted Cost Ratio (95% confidence interval)a
	All Ages ≥18 years	All Ages ≥18 years after excluding transfers
Weighted N	159,624	143,371
Insurance (Reference Private)
Medicare	0.91 (0.88, 0.95)	0.91 (0.88, 0.95)
Medicaid	1.11 (1.06, 1.16)	1.10 (1.05, 1.16)
Uninsured	0.83 (0.79, 0.88)	0.84 (0.79, 0.88)
Age (per year increase)	0.995 (0.994, 0.996)	0.995 (0.994, 0.996)
Household income at zip code level less than $25,000 annually (Reference >$25,000)	0.9 (0.86, 0.94)	0.9 (0.86, 0.94)
Comorbid conditions (Reference none)
Diabetes Mellitus	0.96 (0.92, 0.99)	0.95 (0.91, 0.98)
Congestive heart failure	1.06 (1.00, 1.12)	1.06 (1.002, 1.13)
Charlson Comorbidity Index (per unit increase)	1.06 (1.05, 1.07)	1.05 (1.04, 1.07)
Hospital characteristics
Teaching hospital (Reference non-teaching)	1.16 (1.07, 1.25)	1.14 (1.06, 1.23)
High SAH volume (Reference low volume)	1.35 (1.23, 1.49)	1.30 (1.18, 1.42)
Hospital offering angioplasty (Reference not offering)	1.29 (1.16, 1.44)	1.25 (1.12, 1.39)
Surgery (vs. No surgery)	2.41 (2.30, 2.52)	2.29 (2.19, 2.40)
Hospital complications (per each complication)	1.73 (1.69, 1.77)	1.72 (1.68, 1.76)
Death in hospital (Reference no)	0.57 (0.55, 0.59)	0.54 (0.51, 0.56)

Table shows only variables with at least 0.05 significance level in one of the models.

^aAdjusted cost ratio gives the ratio of the expected cost of a group with respect to the reference category. An adjusted cost ratio of 1.5 means that the expected cost is 150% of the reference category. Adjusted cost ratios were calculated using coefficients that were obtained with weighted multivariable gamma regression, yielding nationally representative estimates for the U.S. population. The models included demographic and socioeconomic information, hospital characteristics, comorbid conditions and hospital mortality status as described in the methods.