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. Author manuscript; available in PMC: 2017 Oct 26.
Published in final edited form as: Med Care. 2015 Jul;53(7):619–629. doi: 10.1097/MLR.0000000000000377

Table 4.

Black-White Differences in Hospital Characteristics, Surgeon Characteristics and Patients’ Socioeconomic Status

Type of Match: Inside the Same Hospital
Risk-Factor Match+ 		Across-Hospital
Risk- Factor Match		 Across-Hospital Procedure Match
SDs are provided for all continuous variables.
Variables		 Matched Blacks
N = 14,917		 Matched Whites
N = 14,917		 P-value All Blacks
N = 18,861		 Matched Whites
N = 18,861		 P-value All Blacks
N = 18,861		 Matched Whites
N = 18,861		 P-value
Hospital Characteristics
Resident-to-bed (R:B) ratio
 % Major (RB > 0.25) 21.2 21.2 1.0000 22.9 12.9 <0.0001 22.9 13.4 <0.0001
 % Minor (0 < RB ≤ 0.25) 30.1 30.1 29.6 24.5 29.6 24.8
 % Non-teaching (RB = 0) 48.6 48.6 47.2 62.5 47.2 61.7
 % Unknown/Missing 0.1 0.1 0.2 0.2 0.2 0.2
Bed Size
 % Large (Size > 250) 76.8 76.8 1.0000 76.1 64.0 <0.0001 76.1 64.4 <0.0001
 % Medium (101≤ Size ≤ 250) 19.5 19.5 19.8 27.1 19.8 26.8
 % Small (Size ≤ 100) 3.6 3.6 3.9 8.8 3.9 8.6
 % Unknown/Missing 0.1 0.1 0.2 0.2 0.2 0.2
Nurse-to-bed (N:B) Ratio*
 % High (N:B > 1.0) 49.2 49.2 1.0000 46.3 49.6 <0.0001 46.3 50.7 <0.0001
 % Moderate (0.5 ≤ N:B ≤ 1.0) 41.6 41.6 43.1 41.9 43.1 40.4
 % Low (N:B ≤ 0.5) 9.1 9.1 10.3 8.4 10.3 8.7
 % Unknown/Missing 0.1 0.1 0.2 0.2 0.2 0.19
Nurse Mix #
 % Advanced Staff (mix > 90% RN) 51.6 51.6 1.0000 49.7 47.5 <0.0001 49.7 47.7 <0.0001
 % Moderate Staff (75% ≤ RN ≤ 90%) 35.7 35.7 37.4 37.0 37.4 36.8
 % Elementary Staff (mix < 75% RN) 11.1 11.1 11.4 14.6 11.4 14.5
 % Unknown/Missing 1.7 1.7 1.6 0.9 1.6 1.0
Technology Index ϯ
 % High Technology 57.5 57.5 1.0000 56.1 51.9 <0.0001 56.1 51.7 < 0.001
 %Unknown/Missing 0.1 0.1 0.2 0.2 0.2 0.2
Type of Financial Control
 % Not-for-profit 79.2 79.2 1.0000 76.3 80.6 <0.0001 76.3 80.9 <0.0001
 % Private 8.0 8.0 9.7 7.2 9.7 7.3
 % Government 12.9 12.9 14.1 12.3 14.1 11.9
Urbanicity
 % Urban 91.9 91.9 1.0000 92.3 82.7 <0.0001 92.3 82.8 <0.0001
Racial Composition of Hospitals’ Patients
 % Admitted to Hospitals > 30% Black 12.5 12.5 1.0000 21.4 2.6 <0.0001 21.4 2.3 <0.0001
 % Admitted to Hospitals 6-30% Black 64.3 64.3 58.6 39.5 58.6 38.8
 % Admitted to Hospitals < 6% Black 23.2 23.2 20.0 57.9 20.0 58.9
Socioeconomic Status of Hospitals’ Patients (Overall, Census 2000 5-digit ZIP)
 % Patients from ZIP ≥ 20% Below Poverty Line 8.4 8.4 1.0000 14.4 4.4 <0.0001 14.4 4.1 <0.0001
 % Patients from ZIP 10-20% Below Poverty Line 50.6 50.6 49.4 44.9 49.4 44.9
 % Patients from ZIP < 10% Below Poverty Line 41.1 41.1 36.1 50.7 36.1 51.0
Surgeon Characteristics
Board-Certified (%)
Yes 38.8 39.6 0.6549 38.5 38.8 0.0054 38.5 38.8 0.0704
No 19.7 19.8 17.8 19.3 17.8 18.9
Missing 41.4 40.5 43.7 41.9 43.7 42.4
Attending Surgeon Years Since Graduation
Number of years (mean) 22.9
(10.5)		 23.0
(10.4)		 0.5349 23.1
(10.5)		 22.6
(10.2)		 <0.0001 23.1
(10.5)		 22.5
(10.2)		 <0.0001
% Missing 2.0 1.6 2.7 1.4 2.7 1.8
Patient Socioeconomic Characteristics
Dual-eligible (%) 32.5 15.0 <0.0001 34.4 14.7 <0.0001 34.4 12.5 <0.0001
Usual Source of Primary Care (%) 59.5 64.0 <0.0001 58.2 64.8 <0.0001 58.2 64.3 <0.0001
Number of Health Care Encounters 2 to 8 Months Prior to Surgery (mean) 4.1
(4.1)		 4.7
(4.5)		 <0.0001 4.0
(4.3)		 4.7
(4.6)		 <0.0001 4.0
(4.3)		 4.6
(4.5)		 <0.0001
Neighborhood Census Median Income ($, mean) 38,703
(15,877)		 48,243
(18,113)		 <0.0001 34,821
(15,595)		 44,266
(17,682)		 <0.0001 34,821
(15,595)		 44,554
(18,072)		 <0.0001
Neighborhood Census Below Poverty Level (mean, %) 18.2
(10.9)		 11.4
(8.4)		 <0.0001 18.9
(11.1)		 10.5
(7.3)		 <0.0001 18.9 10.4
(7.2)		 <0.0001
Neighborhood Census High School Grads (mean, %) 74.9
(11.6)		 81.0
(11.0)		 <0.0001 74.1
(12.0)		 81.3
(10.1)		 <0.0001 74.1
(12.0)		 81.6
(10.0)		 <0.0001
Neighborhood Isolation Index^ (mean) 0.61
(0.16)		 0.60
(0.17)		 <0.0001 0.63
(0.16)		 0.54
(0.21)		 <0.0001 0.63
(0.16)		 0.54
(0.21)		 <0.0001
Neighborhood Dissimilarity Index^^ (mean) 0.68
(0.10)		 0.67
(0.10)		 <0.0001 0.68
(0.10)		 0.64
(0.11)		 <0.0001 0.68
(0.10)		 0.64
(0.11)		 <0.0001

P-values were calculated using the Chi-square test.

Data for hospital characteristics was taken from Medicare Providers of Service (POS) file for 2005, the midpoint of the study data used for matching. Surgeon characteristics were obtained from Medicare Physician Identification and Eligibility Records (MPIER).

+

In the Inside-Hospital Match, blacks and whites are always matched within the same hospital, so the distribution of hospitals in this match is identical.

*

Nurse-to-bed ratio is calculated by dividing the number of full-time equivalent (FTE) nurses (registered nurses and licensed practical nurses) by the total number of beds.

#

Nurse mix is the ratio of registered nurses to the number of full-time equivalent nurses.

ϯ

High technology is noted as the presence of a burn unit, or the provision of coronary artery bypass graft (CABG) or organ transplantation at the hospital.

^

The isolation index is a measure of the likelihood of minorities and whites coming onto contact with each other (1 = lowest exposure of minorities to whites).

^^

The dissimilarity index is a measure of the evenness of distribution of races- the proportion of minorities who would have to change locations for race to be evenly distributed (1 = complete segregation; 0 = complete integration).