Table 1.
Patient characteristics in relation to groups of population density.
| OHCA according to population density groups (18,248) |
||||||
|---|---|---|---|---|---|---|
| Low (<300/km2) | Medium (300–1499/km2) | High (1500–2999/km2) | Very high (≥3000/km2) | p-value | Missing data, n (%) | |
| Number of OHCA | 721 (4.0) | 6939 (38.0) | 7001 (38.4) | 3587 (19.7) | – | – |
| Patient factors | ||||||
| Median age (IQR) | 69 (61–76) | 72 (62–80) | 72 (62–81) | 73 (62–83) | <0.001 | – |
| Female sex, n (%) | 181 (25.1) | 2118 (30.5) | 2282 (32.6) | 1335 (37.2) | <0.001 | – |
| Comorbidities: | ||||||
| - Peripheral vascular disease, n (%) | 82 (11.4) | 774 (11.2) | 819 (11.7) | 408 (11.4) | 0.794 | – |
| - Ischemic heart disease incl. previous myocardial infarction, n (%) | 198 (27.5) | 2008 (28.9) | 2004 (28.6) | 976 (27.2) | 0.265 | – |
| - Arrhythmia, n (%) | 129 (17.9) | 1309 (18.9) | 1450 (20.7) | 755 (21.1) | 0.007 | – |
| - Congestive heart failure, n (%) | 126 (17.5) | 1330 (19.2) | 1531 (21.9) | 881 (24.6) | <0.001 | – |
| - Diabetes, n (%) | 110 (15.3) | 1109 (16.0) | 1110 (15.9) | 596 (16.6) | 0.704 | – |
| - COPD, n (%) | 74 (10.3) | 1010 (14.6) | 994 (14.2) | 589 (16.4) | <0.001 | – |
| - Malignancy, n (%) | 69 (9.6) | 708 (10.2) | 872 (12.5) | 469 (13.1) | <0.001 | – |
| Cardiac arrest-related factors | ||||||
| Arrest in public, n (%) | 226 (32.8) | 1434 (22.2) | 1626 (24.5) | 1020 (29.1) | <0.001 | 958 (5.3) |
| Witnessed arrests, n (%) | 394 (55.0) | 3633 (52.7) | 3656 (52.6) | 1535 (59.6) | <0.001 | 1102 (6.0) |
| Bystander CPR, n (%) | 324 (45.1) | 2948 (42.6) | 2494 (35.8) | 883 (34.3) | <0.001 | 1074 (5.9) |
| - Bystander CPR in witnessed arrests, n (%) | 196 (49.9) | 1836 (50.7) | 1628 (44.7) | 602 (39.4) | <0.001 | 31 (0.3) |
| - Bystander CPR in EMS response time <10 min, n (%) | 81 (37.9) | 980 (39.4) | 1155 (35.9) | 351 (35.1) | 0.024 | 21 (0.3) |
| AED use by bystander, n (%) | 17 (2.4) | 167 (2.4) | 134 (2.0) | 32 (1.5) | 0.057 | 1701 (9.3) |
| - AED use by bystander in witnessed arrests, n (%) | 16 (4.1) | 128 (3.5) | 108 (3.1) | 29 (2.3) | 0.137 | 423 (4.6) |
| Median EMS response time (estimated median time from recognition of arrest to EMS arrival) (IQR) | 14 (9–22) | 13 (8–20) | 10 (6–16) | 10 (6–16) | <0.001 | 3069 (16.8) |
| Shockable heart rhythm, n (%) | 194 (28.1) | 1807 (27.4) | 1908 (28.6) | 860 (28.5) | 0.437 | 1264 (6.9) |
| Outcomes | ||||||
| Survival upon hospital arrival, n (%) | 81 (11.5) | 1012 (14.8) | 1184 (17.6) | 513 (24.7) | <0.001 | 1913 (10.5) |
| 30-day survival, n (%) | 38 (5.3) | 487 (7.0) | 621 (8.9) | 367 (10.2) | <0.001 | – |
| - 30-day survival in survivors upon hospital arrival, n (%) | 36 (44.4) | 461 (45.6) | 575 (48.6) | 225 (43.9) | 0.265 | – |
COPD = chronic obstructive pulmonary disease; EMS = emergency medical service; IQR = interquartile range; OHCA = out-of-hospital cardiac arrest