Table 1. Summary Statistics of High-Income vs Low-Income Communitiesa.
| Variable | Mean (SD) | Difference | P Value | |
|---|---|---|---|---|
| High Income (n = 37 550) | Low Income (n = 8192) | |||
| Patient Characteristicsb | ||||
| Age, y | 60.82 (19.55) | 59.84 (17.29) | 0.98 | <.001 |
| White race/ethnicity | 0.70 (0.46) | 0.62 (0.48) | 0.08 | <.001 |
| Male | 0.59 (0.49) | 0.54 (0.50) | 0.05 | <.001 |
| Health insurance | ||||
| Private | 0.29 (0.46) | 0.16 (0.37) | 0.14 | <.001 |
| Medicaid | 0.16 (0.37) | 0.38 (0.49) | −0.22 | <.001 |
| Medicare | 0.37 (0.48) | 0.35 (0.48) | 0.02 | .02 |
| Uninsured | 0.15 (0.36) | 0.08 (0.27) | 0.07 | <.001 |
| Other | 0.02 (0.15) | 0.03 (0.16) | 0.00 | .18 |
| Response Characteristicsc,d | ||||
| Urban zip code | 0.93 (0.25) | 0.61 (0.49) | 0.32 | <.001 |
| Driving distance, incident to hospital miles | 6.08 (7.30) | 6.77 (13.65) | −0.69 | <.001 |
| Weekday | 0.72 (0.45) | 0.72 (0.45) | 0.00 | .87 |
| Weekend | 0.72 (0.45) | 0.72 (0.45) | 0.00 | .87 |
| 7 am to 3 pm | 0.36 (0.48) | 0.40 (0.49) | −0.04 | <.001 |
| 3 pm to 11 pm | 0.37 (0.48) | 0.33 (0.47) | 0.04 | <.001 |
| 11 pm to 7 am | 0.26 (0.44) | 0.27 (0.44) | 0.00 | .73 |
| Northeast | 0.37 (0.48) | 0.47 (0.50) | −0.10 | <.001 |
| Midwest | 0.18 (0.38) | 0.06 (0.24) | 0.12 | <.001 |
| South | 0.33 (0.47) | 0.46 (0.50) | −0.13 | <.001 |
| West | 0.12 (0.33) | 0.02 (0.12) | 0.10 | <.001 |
| Time measure, min | ||||
| Response time | 8.24 (4.46) | 9.08 (5.67) | −0.84 | <.001 |
| On-scene time | 18.70 (9.34) | 21.91 (13.35) | −3.20 | <.001 |
| Transport time | 10.54 (7.31) | 12.04 (9.35) | −1.50 | <.001 |
| Total EMS time | 37.49 (13.61) | 43.02 (18.83) | −5.54 | <.001 |
| Response time benchmarks, min | ||||
| <4 | 0.31 (0.46) | 0.30 (0.46) | 0.01 | <.001 |
| <8 | 0.78 (0.41) | 0.72 (0.45) | 0.06 | <.001 |
| <15 | 0.97 (0.18) | 0.93 (0.26) | 0.04 | <.001 |
Abbreviation: EMS, emergency medical services.
The highest median zip code income quartile ranges from $57 502 to $113 313, and the lowest median zip code income quartile ranges from $20 250 to $42 642. Percentages may not sum to 100% because of rounding. The column showing the difference between high-income and low-income areas may not always exactly reflect the difference because of rounding.
Only 12 288 of 37 550 patients (32.7%) from high-income zip codes and 4647 of 8192 patients (56.7%) from low-income zip codes had all demographic data collected.
Weekday and weekend are reported in the summary table, but individual day indicators are included in the regression. Hours are reported in intervals in the summary table, but hour indicators are included in the regression (eg, 12 am to 1 am).
US Census divisions are reported as regions in the summary table, but individual divisions are included in the regression. See eTable 1 in the Supplement for US Census division and region definitions.