Using clinical variables and drug prescription data to control for confounding in outcome comparisons between hospitals

Table 2 Predictive models for 30-day mortality after AMI admission (No. 7613)

Risk factor	n (admissions)	Crude OR	Hospital discharge data		Hospital discharge data + clinical variables + drug prescriptions
			Adjusted OR	P	Adjusted OR	P
Age	-	1.08	1.08	0.000	1.08	0.000
Gender (females vs males)	2690	1.66	0.97	0.738	0.96	0.589
Cancer	437	1.87	1.44	0.008	1.42	0.013
Diabetes	829	1.54	1.34	0.013
Disorders of lipid metabolism	344	0.42	0.42	0.001	0.46	0.004
Blood disorders (index admission)	393	1.39			0.69	0.027
Blood disorders	338	2.34			1.28	0.127
Previous AMI	1137	0.85	0.76	0.033	0.71	0.010
Heart failure	554	2.55	1.66	0.000	1.51	0.003
Other forms of ischemic heart disease (index admission)	175	0.88	0.48	0.009	0.47	0.008
Other forms of ischemic heart disease	103	1.41	1.33	0.384	1.26	0.478
Chronic renal disease	419	2.68	1.65	0.000	1.48	0.007
Other chronic disease (liver, pancreas, intestine)	85	2.08			1.92	0.035
Previous CABG	310	0.50	0.50	0.007	0.52	0.012
Previous PCI	854	0.47	0.61	0.004	0.62	0.006
Blood pressure > 100	6592	1.00			1.00	-
Blood pressure < =100	765	4.07			4.60	0.000
Blood pressure missing	256	1.27			1.33	0.195
Diuretics (3 months)	1577	2.54			1.69	0.000
ACE inhibitors (3 months)	1977	1.12			0.77	0.005
Angiotensin II antagonists (3 months)	1823	1.01			0.82	0.039
Area under ROC curve			0.761		0.797

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