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Table 1 Baseline characteristics of unmatched and matched patients

From: Dispatcher instructions for bystander cardiopulmonary resuscitation and neurologically intact survival after bystander-witnessed out-of-hospital cardiac arrests: a nationwide, population-based observational study

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
  1. Values are reported as n (%) unless indicated otherwise
  2. ASD absolute standardsed difference; DA-CPR dispatcher-assisted cardiopulmonary resuscitation; PS propensity score; SD standard deviation
  3. aAn ASD of equal or more than 0.1 was considered to indicate a substantial imbalance between the two groups
  4. bThe rural area constituted 19 prefectures with a population of less than 200 inhabitants per km2