Table 4.
ECG Utilization (%) in the Risk Factor Dataset that Included ≈124000 Individuals With Chest Pain Transported by North Carolina EMS Agencies in 2008 to 2010 Summarized by Characteristics Included in 4 Multivariable Models
| No ECG Performed | ECG Performed | Single Variable P Value | RR (95% CI) | Multi‐variable P Value | |
|---|---|---|---|---|---|
| Clinical Characteristics | |||||
| Age Groups, y | 0.34 | 0.20 | |||
| 30 to 50 | 13 960 (38.5%) | 22 319 (61.5%) | [Reference] | ||
| 50 to 70 | 19 250 (37.8%) | 31 702 (62.2%) | 1.01 (1.00, 1.03) | ||
| 70 to 80 | 6949 (36.9%) | 11 901 (63.1%) | 1.01 (0.98, 1.04) | ||
| ≥80 | 6853 (38.2%) | 11 097 (61.8%) | 0.99 (0.97, 1.00) | ||
| Gender | <0.01 | <0.05 | |||
| Female | 25 372 (38.7%) | 40 222 (61.3%) | [Reference] | ||
| Male | 21 640 (37.0%) | 36 797 (63.0%) | 1.02 (1.01, 1.04) | ||
| Race | <0.01 | <0.05 | |||
| Black or African American | 14 235 (42.8%) | 18 986 (57.2%) | 0.95 (0.84, 1.07) | ||
| Other race | 1626 (17.5%) | 7687 (82.5%) | 1.27 (1.02, 1.56) | ||
| White | 31 151 (38.2%) | 50 346 (61.8%) | [Reference] | ||
| Hypotension, SBP <90 | 0.05 | <0.05 | |||
| No | 37 228 (33.4%) | 74 274 (66.6%) | [Reference] | ||
| Yes | 665 (29.7%) | 1576 (70.3%) | 1.05 (1.00, 1.09) | ||
| High Pulse Rate, >100 | 0.06 | <0.05 | |||
| No | 29 698 (33.8%) | 58 283 (66.2%) | [Reference] | ||
| Yes | 7804 (31.7%) | 16 831 (68.3%) | 1.03 (1.00, 1.06) | ||
| Ride Characteristics | |||||
| Age Groups, y | 0.34 | 0.18 | |||
| 30 to 50 | 13 960 (38.5%) | 22 319 (61.5%) | [Reference] | ||
| 50 to 70 | 19 250 (37.8%) | 31 702 (62.2%) | 1.01 (1.00, 1.02) | ||
| 70 to 80 | 6949 (36.9%) | 11 901 (63.1%) | 1.01 (0.98, 1.03) | ||
| ≥80 | 6853 (38.2%) | 11 097 (61.8%) | 0.99 (0.98, 1.01) | ||
| Gender | <0.01 | <0.05 | |||
| Female | 25 372 (38.7%) | 40 222 (61.3%) | [Reference] | ||
| Male | 21 640 (37.0%) | 36 797 (63.0%) | 1.03 (1.01, 1.04) | ||
| Race | <0.01 | 0.12 | |||
| Black or African American | 14 235 (42.8%) | 18 986 (57.2%) | 0.98 (0.89, 1.09) | ||
| Other race | 1626 (17.5%) | 7687 (82.5%) | 1.21 (1.01, 1.46) | ||
| White | 31 151 (38.2%) | 50 346 (61.8%) | [Reference] | ||
| Transport Time, min | <0.01 | <0.05 | |||
| 03 to 13 | 2278 (67.9%) | 1078 (32.1%) | 0.53 (0.46, 0.62) | ||
| 13 to 18 | 3974 (47.3%) | 4425 (52.7%) | 0.84 (0.77, 0.91) | ||
| 18 to 23 | 6512 (40.1%) | 9722 (59.9%) | 0.94 (0.88, 1.00) | ||
| 23 to 28 | 7920 (36.8%) | 13 600 (63.2%) | 0.99 (0.95, 1.04) | ||
| 28 to 33 | 7745 (35.8%) | 13 895 (64.2%) | 1.01 (0.97, 1.05) | ||
| >33 | 18 583 (35.1%) | 34 299 (64.9%) | [Reference] | ||
| Time of Day | 0.38 | 0.40 | |||
| Daytime | 20 895 (38.2%) | 33 794 (61.8%) | [Reference] | ||
| Evening | 16 508 (37.3%) | 27 761 (62.7%) | 1.01 (0.99, 1.02) | ||
| Overnight | 9609 (38.3%) | 15 464 (61.7%) | 0.99 (0.97, 1.02) | ||
| Weekend | 0.12 | 0.08 | |||
| Weekday | 35 001 (38.1%) | 56 838 (61.9%) | [Reference] | ||
| Weekend | 12 011 (37.3%) | 20 181 (62.7%) | 1.01 (1.00, 1.02) | ||
| Service Year | 0.02 | <0.05 | |||
| 2008 | 17 086 (43.3%) | 22 376 (56.7%) | [Reference] | ||
| 2009 | 15 750 (36.0%) | 28 026 (64.0%) | 1.13 (1.02, 1.25) | ||
| 2010 | 14 176 (34.8%) | 26 617 (65.2%) | 1.14 (0.99, 1.30) | ||
| Highest Crew Certification | <0.01 | <0.05 | |||
| Nonparamedic | 6697 (69.3%) | 2961 (30.7%) | [Reference] | ||
| Paramedic | 40 315 (35.2%) | 74 058 (64.8%) | 2.15 (1.55, 2.99) | ||
| System Characteristics | |||||
| Age Groups | 0.34 | <0.05 | |||
| 30 to 50 | 13 960 (38.5%) | 22 319 (61.5%) | [Reference] | ||
| 50 to 70 | 19 250 (37.8%) | 31 702 (62.2%) | 1.01 (1.00, 1.02) | ||
| 70 to 80 | 6949 (36.9%) | 11 901 (63.1%) | 1.01 (0.99, 1.02) | ||
| ≥80 | 6853 (38.2%) | 11 097 (61.8%) | 0.99 (0.97, 1.00) | ||
| Gender | <0.01 | <0.05 | |||
| Female | 25 372 (38.7%) | 40 222 (61.3%) | [Reference] | ||
| Male | 21 640 (37.0%) | 36 797 (63.0%) | 1.02 (1.01, 1.03) | ||
| Race | <0.01 | <0.05 | |||
| Black or African American | 14 235 (42.8%) | 18 986 (57.2%) | 0.96 (0.89, 1.03) | ||
| Other race | 1626 (17.5%) | 7687 (82.5%) | 1.13 (1.04, 1.24) | ||
| White | 31 151 (38.2%) | 50 346 (61.8%) | [Reference] | ||
| Agency Type | 0.19 | 0.10 | |||
| Community, nonprofit | 6377 (55.4%) | 5125 (44.6%) | 0.79 (0.59, 1.07) | ||
| Private/hospital | 6443 (41.1%) | 9240 (58.9%) | 0.90 (0.78, 1.05) | ||
| Public governmental | 34 192 (35.3%) | 62 654 (64.7%) | [Reference] | ||
| System Capability | <0.01 | <0.05 | |||
| 0% | 1030 (99.1%) | 9 (0.9%) | 0.01 (0.00, 0.06) | ||
| >0% to <25% | 1718 (94.5%) | 100 (5.5%) | 0.08 (0.03, 0.24) | ||
| 25% to <50% | 1437 (55.5%) | 1150 (44.5%) | 0.67 (0.37, 1.24) | ||
| 50% to <75% | 5811 (41.8%) | 8105 (58.2%) | 0.76 (0.61, 0.94) | ||
| 75% to <100% | 24 821 (51.1%) | 23 796 (48.9%) | 0.70 (0.58, 0.85) | ||
| 100% | 12 195 (21.8%) | 43 859 (78.2%) | [Reference] | ||
| Rural | 0.79 | 0.77 | |||
| No | 32 052 (37.2%) | 54 032 (62.8%) | 0.99 (0.89, 1.10) | ||
| Yes | 14 960 (39.4%) | 22 987 (60.6%) | [Reference] | ||
| Spatial Characteristics | |||||
| Age Groups | 0.34 | <0.05 | |||
| 30 to 50 | 13 960 (38.5%) | 22 319 (61.5%) | [Reference] | ||
| 50 to 70 | 19 250 (37.8%) | 31 702 (62.2%) | 1.01 (1.00, 1.02) | ||
| 70 to 80 | 6949 (36.9%) | 11 901 (63.1%) | 1.01 (0.98, 1.03) | ||
| ≥80 | 6853 (38.2%) | 11 097 (61.8%) | 0.98 (0.96, 1.00) | ||
| Gender | <0.01 | <0.05 | |||
| Female | 25 372 (38.7%) | 40 222 (61.3%) | [Reference] | ||
| Male | 21 640 (37.0%) | 36 797 (63.0%) | 1.03 (1.01, 1.04) | ||
| Race | <0.01 | 0.12 | |||
| Black or African American | 14 235 (42.8%) | 18 986 (57.2%) | 0.99 (0.91, 1.07) | ||
| Other race | 1626 (17.5%) | 7687 (82.5%) | 1.22 (1.10, 1.36) | ||
| White | 31 151 (38.2%) | 50 346 (61.8%) | [Reference] | ||
| Area | 0.03 | <0.05 | |||
| Region 01 | 4272 (30.1%) | 9903 (69.9%) | 1.04 (0.88, 1.23) | ||
| Region 02 | 4897 (30.1%) | 11 398 (69.9%) | 1.03 (0.78, 1.36) | ||
| Region 03 | 8592 (65.0%) | 4627 (35.0%) | 0.49 (0.32, 0.73) | ||
| Region 04 | 6660 (70.5%) | 2791 (29.5%) | 0.71 (0.43, 1.17) | ||
| Region 05 | 6878 (46.0%) | 8069 (54.0%) | 0.74 (0.58, 0.94) | ||
| Region 06 | 7786 (25.6%) | 22 587 (74.4%) | [Reference] | ||
| Region 07 | 1890 (35.5%) | 3439 (64.5%) | 0.87 (0.58, 1.30) | ||
| Region 08 | 2539 (30.1%) | 5901 (69.9%) | 0.96 (0.73, 1.27) | ||
| Region 09 | 2514 (26.1%) | 7124 (73.9%) | 1.00 (0.85, 1.17) | ||
| Region 10 | 803 (42.5%) | 1086 (57.5%) | 0.77 (0.50, 1.19) | ||
| Region 11 | 181 (65.8%) | 94 (34.2%) | 0.49 (0.37, 0.64) | ||
Age, Gender, and Race were included in all 4 models. ECG indicates electrocardiography; RR, relative risk; EMS, emergency medical services; CI, confidence interval; SBP, systolic blood pressure.