Table 1.
Baseline characteristics of unmatched and matched patients
| Characteristic | Pre-propensity score matching | Post-propensity score matching | ||||
|---|---|---|---|---|---|---|
| Conventional DA-CPR | Compression-only DA-CPR | ASDa | Conventional DA-CPR | Compression-only DA-CPR | ASDa | |
| (n = 2169) | (n = 22,778) | (n = 2169) | (n = 2169) | |||
| Year | ||||||
| 2016 |
1070 (49.3) |
11,065 (48.6) |
0.02 |
1070 (49.3) |
1084 (50.0) |
0.01 |
| 2017 |
1099 (50.7) |
11,713 (51.4) |
0.02 |
1099 (50.7) |
1085 (50.0) |
0.01 |
| Sex, male |
1151 (53.1) |
13,416 (58.9) |
0.12 |
1151 (53.1) |
1154 (53.2) |
0.00 |
| Age, y, mean (SD) |
76.7 (15.7) |
76.5 (14.8) |
0.01 |
76.7 (15.7) |
77.2 (14.9) |
0.04 |
| Rural regionsb |
507 (23.4) |
5649 (24.8) |
0.03 |
507 (23.4) |
424 (19.6) |
0.09 |
| Witnessed by family member |
944 (43.5) |
15,028 (66.0) |
0.46 |
944 (43.5) |
951 (43.9) |
0.01 |
| Presumed cardiac cause |
1292 (59.6) |
13,783 (60.5) |
0.02 |
1292 (59.6) |
1309 (60.4) |
0.02 |
| Call-to-response time, min, mean (SD) |
10.1 (4.3) |
9.5 (3.9) |
0.14 |
10.1 (4.3) |
10.1 (4.2) |
0.01 |
| Initial shockable rhythm |
304 (14.0) |
3463 (15.2) |
0.03 |
304 (14.0) |
297 (13.7) |
0.01 |
| Advanced airway management |
1052 (48.5) |
10,530 (46.2) |
0.05 |
1052 (48.5) |
979 (45.1) |
0.07 |
| Epinephrine administration |
702 (32.4) |
7565 (33.2) |
0.02 |
702 (32.4) |
711 (32.8) |
0.01 |
| Collapse-to-initiation of DA-CPR time, min, mean (SD) |
3.7 (5.2) |
4.7 (5.9) |
0.17 |
3.7 (5.2) |
4.2 (5.6) |
0.09 |
| Duration of DA-CPR, min, mean (SD) |
8.1 (4.0) |
7.5 (3.7) |
0.17 |
8.1 (4.0) |
7.9 (4.0) |
0.05 |
Values are reported as n (%) unless indicated otherwise
ASD absolute standardsed difference; DA-CPR dispatcher-assisted cardiopulmonary resuscitation; PS propensity score; SD standard deviation
aAn ASD of equal or more than 0.1 was considered to indicate a substantial imbalance between the two groups
bThe rural area constituted 19 prefectures with a population of less than 200 inhabitants per km2