TABLE 3—
Effect of Socioeconomic Status on Observed and Predicted Mortality Rates for Pediatric Trauma Patients in Sacramento County, 1988–1998
| Survivors | Deaths | |||||||
| N | Mean Predicted Mortality | Observed | Predicted | Observed | Predicted | Standardized Mortality Ratioa (95% Confidence Interval) | Z Score | |
| Overall | 3855 | 3.39 | 3724 | 3724 | 131 | 131 | 1.00 | 0 |
| Median household income ($) | ||||||||
| 0–15 000 | 398 | 2.79 | 384 | 387 | 14 | 11 | 1.27 (0.69, 2.14) | 1.63 |
| 15 001–25 000 | 1009 | 3.65 | 969 | 972 | 40 | 37 | 1.08 (0.77, 1.47) | 0.56 |
| 25 001–35 000 | 1099 | 3.11 | 1069 | 1064 | 30 | 35 | 0.86 (0.58, 1.22) | −1.33 |
| 35 001–45 000 | 867 | 3.35 | 841 | 838 | 26 | 29 | 0.89 (0.59, 1.31) | −0.93 |
| > 45 000 | 482 | 4.09 | 461 | 462 | 21 | 20 | 1.05 (0.65, 1.60) | 0.37 |
| Below poverty line (%) | ||||||||
| < 1 | 359 | 3.06 | 348 | 347 | 11 | 12 | 0.92 (0.46, 1.64) | −0.43 |
| 1–20 | 1557 | 3.79 | 1498 | 1496 | 58 | 61 | 0.95 (0.72, 1.23) | −0.66 |
| 21–50 | 1296 | 2.93 | 1258 | 1258 | 38 | 38 | 1.1 (0.70, 1.37) | 0 |
| > 50 | 643 | 3.58 | 620 | 623 | 23 | 20 | 1.15 (0.73, 1.73) | 1.19 |
| Insurance | ||||||||
| Other | 2256 | 3.50 | 2183 | 2177 | 73 | 79 | 0.92 (0.72, 1.12) | −1.26 |
| Medicaid | 1599 | 3.25 | 1541 | 1547 | 58 | 51 | 1.14 (0.86, 1.47) | 1.49 |
aStandardized mortality ratio equals observed number of deaths divided by predicted number of deaths.