Table 2.
Characteristics of Markets with Low, Medium, and High Segregation of AMI Admissions across Hospitals as Determined by the Dissimilarity Index and by the Isolation Index
| Dissimilarity Based on AMI Admissions |
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|---|---|---|---|---|---|
| Mean (SD) |
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| Market Characteristic | Low (0.11–0.28) | Medium (>0.28–0.42) | High (>0.42–0.77) | p Value* | Correlation (Pearson's r) for Market Characteristic and Isolation (p Value)† |
| Residential dissimilarity index | 0.50 (0.11) | 0.58 (0.13) | 0.71 (0.09) | <.001 | 0.71 (p<.001) |
| Total CMS part A enrollees (1,000) | 102 (77) | 190 (117) | 291 (168) | <.001 | 0.53 (p<.001) |
| Percent part A enrollees who are black | 17.6% (8.6) | 11.6% (8.3) | 11.9% (9.0) | .006 | −0.15 (p=.12) |
| Number of hospitals admitting AMI | 11.8 (5.2) | 18.8 (11.3) | 28.0 (17.6) | <.001 | 0.48 (p<.001) |
| Number of hospitals performing revascularization | 3.5 (2.0) | 7.3 (4.5) | 12.4 (7.3) | <.001 | 0.61 (p<.001) |
| Proportion of hospitals with membership in the Council of Teaching Hospitals (COTH) | 7.6% (7.2) | 7.8% (6.8) | 10.1% (9.3) | .20 | 0.23 (p=.02) |
| Hospital beds per 1,000 population | 3.5 (0.8) | 2.9 (0.6) | 3.0 (0.6) | .002 | −0.18 (p=.07) |
| Persons per square mile | 913 (4,315) | 482 (719) | 1,641 (3,842) | .37 | 0.16 (p=.11) |
| Percent of population with income US$75,000 | 21.1% (6.1) | 29.4% (9.9) | 30.9% (7.8) | <.001 | 0.43 (p<.001) |
| Percent enrollment in CMS Managed Care | 4.7% (7.3) | 13.3% (13.8) | 16.0% (14.5) | <.001 | 0.29 (p=.003) |
| Isolation Based on AMI Admissions |
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| Mean (SD) |
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| Market Characteristic | Low (0.05–0.14) | Medium (>0.14–0.27) | High (>0.27–0.77) | p Value* | Correlation (Pearson's r) for Market Characteristic and Isolation (p Value)† |
| Residential Isolation category | 0.40 (0.12) | 0.51 (0.10) | 0.66 (0.12) | <.001 | 0.75 (p<.001) |
| Total CMS part A enrollees (1,000) | 195 (138) | 167 (115) | 222 (180) | .43 | 0.14 (p=.14) |
| Percent CMS enrollees who are black | 6.4 (2.8) | 12.5 (6.5) | 22.2 (8.1) | <.001 | 0.75 (p<.001) |
| Number of hospitals admitting AMI | 16.6 (10.3) | 18.1 (11.3) | 23.9 (18.4) | .20 | 0.22 (p=.02) |
| Number of hospitals performing revascularization | 6.3 (4.5) | 7.0 (5.6) | 9.9 (7.8) | .14 | 0.28 (p=.004) |
| Proportion of hospitals with membership in the Council of Teaching Hospitals (COTH) | 7.6 (7.2) | 5.8 (5.5) | 10.9 (13.6) | .12 | 0.30 (p=.002) |
| Hospital beds per 1,000 population | 2.9 (0.6) | 3.1 (0.6) | 3.3 (0.9) | .18 | 0.17 (p=.09) |
| Persons per square mile | 309 (272) | 504 (902) | 2,222 (5,607) | .04 | 0.36 (p<.001) |
| Percent of population with income US$75,000 | 27.8% (9.5) | 27.0% (9.8) | 26.9% (8.2) | .99 | 0.04 (p=.69) |
| Percent enrollment in CMS managed care | 12.6% (13.0) | 11.4% (14.1) | 10.0% (12.4) | .54 | −0.05 (p=.69) |
*
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.