Table 3.

Mean Risk-Adjusted Relative Hazard of Revascularization within 90 Days for Black and White Patients in 105 Markets Categorized as Low, Medium, and High Segregation by the Dissimilarity or Isolation Index, and Correlation of Market-Level Relative Hazard Ratios to the Dissimilarity and Isolation Index^*,

	Low	Medium	High	p Value†	Pearson's r‡
Dissimilarity segregation category
All markets (n=105)
Dissimilarity across hospitals	0.65	0.79	0.73	.002	r=0.16; p=.10
	(0.60–0.71; p<.001)	(0.74–0.84; p<.001)	(0.68–0.78; p<.001)
Dissimilarity by residence	0.67	0.73	0.78	.03	r=0.26, p<.008
	(0.62–0.73; p<.001)	(0.67–0.78; p<.001)	(0.72–0.83; p<.001)
Hospital Dissimilarity by region
Midwest (n=19 markets)	0.90	0.93	0.75	.25	r=0.36; p=.13
	(0.63–1.18; p=.25)	(0.70–1.15; p=.27)	(0.65–0.85; p<.001)
Northeast (n=16 markets)	0.72	0.71	0.76	.83	r=0.11; p=.70
	(0.49–0.95; p=.009)	(0.58–0.84; p<.001)	(0.64–0.89; p<.001)
South (n=63 markets)	0.63	0.78	0.71	.001	r=0.26; p=.04
	(0.59–0.68; p<.001)	(0.72–0.84; p<.001)	(0.61–0.80; p<.001)
West (n=8 markets)	—	0.89	0.67	.17	r=0.20; p=.64
		(0.62–1.17; p=.23)	(0.45–0.88; p=.001)
Isolation segregation category
All markets (n=105)
Isolation across hospitals	0.78	0.71	0.69	.06	r=0.14; p=.15
	(0.72–0.83; p<.001)	(0.65–0.76; p<.001)	(0.64–0.74; p<.001)
Isolation by residence	0.71	0.76	0.71	.33	r=0.01, p=.98
	(0.65–0.76; p<.001)	(0.70–0.81; p<.001)	(0.65–0.76; p<.001)
Hospital Isolation by region
Midwest (n=18 markets)	0.94	0.77	0.73	.13	r=0.38; p=.11
	(0.77–1.11; p=.24)	(0.61–0.92; p=.002)	(0.59–0.86; p<.001)
Northeast (n=16 markets)	0.77	0.57	0.77	.09	r=0.10; p=.72
	(0.68–0.87; p=.05)	(0.41–0.74; p=.05)	(0.63–0.91; p=.04)
South (n=63 markets)	0.76	0.68	0.66	.10	r=0.21; p=.10
	(0.69–0.83; p<.001)	(0.62–0.74; p<.001)	(0.60–0.72; p<.001)
West (n=8 markets)	0.62	0.91	0.71	.27	r=0.10; p=.82
	(0.33–0.91; p=.005)	(0.62–1.20; p=.28)	(0.36–1.07; p=.06)

^*Hazard of revascularization in black patients relative to white patients was estimated separately for 105 HRR markets, using Cox regression models to adjust for sociodemographic factors (age, gender, zip code–level median income), comorbidities (diabetes, congestive heart failure, chronic obstructive lung disease, peripheral vascular disease, cerebrovascular disease, valvular disease, metastatic cancer, arrhythmia, neurological disease, renal failure, fluid and electrolyte imbalance, and weight loss), AMI location (anterior/lateral, inferior/posterior, subendocardial, and other site), the use of mechanical ventilation on day of admission, and distance to nearest hospital performing revascularization.

^†p value for comparing market characteristics across segregation categories was determined using F-test with ANOVA procedure.

^‡p value for Pearson's r.

AMI, acute myocardial infarction; HRR, hospital referral regions.