Table 1.

Baseline characteristics of study cohort, by race.

Characteristics	All (n=1,190,510)	Black (n=94,541)	White (n=1,095,969)	p-value⁎
Demographic features
Black (%)	7.9	–	–
Male (%)	41.1	37.3	41.4	<0.001
Age in years (mean±SD)	76.5±7.3	75.7±7.3	76.6±7.3	<0.001
Age group				<0.001
66–70 years (%)	25.4	29.9	25.0
71–75 years (%)	24.2	25.4	24.1
76–80 years (%)	21.4	19.8	21.6
81–85 years (%)	16.1	13.8	16.3
≥86 years (%)	12.9	11.2	13.0
Health-related measures
Hospitalization/Charlson score				<0.001
No hospitalization	78.5	75.4	78.8
Charlson score=0	6.0	5.0	6.1
Charlson score=1	6.0	6.5	5.9
Charlson score=2	4.2	5.0	4.2
Charlson score=3	2.4	3.2	2.3
Charlson score=4	1.2	1.9	1.2
Charlson score=5 or more	1.7	3.1	1.6
ESRD status (%)	0.4	1.7	0.3	<0.001
Disabilitya (%)	7.6	15.0	7.0	<0.001
State Medicaid/Buy-In Status (%)	10.7	31.9	8.9	<0.001
Residential measures
Median household income (median, interquartile range)	$40,881	$26,371	$41,773	<0.001
	$33,668–$52,146	$20,423-$35,523	$34,936-$53,100
Median household income group				<0.001
$2500 –<$20,000 (%)	2.2	22.7	0.5
$20,000– <$30,000 (%)	11.4	39.4	8.9
$30,000– <$40,000 (%)	33.0	20.5	34.1
$40,000–<$50,000 (%)	24.0	9.3	25.3
$50,000– <$60,000 (%)	14.0	4.4	14.8
$60,000– <$70,000 (%)	7.4	1.8	7.9
≥$70,000 (%)	8.0	2.0	8.5
Racial segregationb				<0.001
1st quartile (%)	12.1	11.4	12.2
2nd quartile (%)	19.7	11.4	20.5
3rd quartile (%)	24.2	19.4	24.6
4th quartile (%)	43.9	57.9	42.7

ESRD: end-stage renal disease.

Note: Values expressed as mean, standard deviation; median, interquartile range; or percent.

^⁎T-test for continuous variables, chi-square test for categorical variables, and Wilcoxon–Mann–Whitney test for median comparison.

^aBased on original eligibility categories of Medicare enrollment.

^bQuartile definitions for racial segregation: <39.50, 39.50–<49.00, 49.00–<58.50, and ≥58.50.