Table 1 Characteristics of included studies

1

Cummins(1985) [28]

Washington, America (1976.04–1983.09)

OHCAs (1297)

Mean 64.7

N/A

1.survival to hospital discharge

Witnessed arrest, age, sex, and EMS response time

2

Swor(1995) [29]

Oakland, American (1989.06–1993.06)

OHCAs (722)

VT/VF (476)

65.9

ALS/BLS

6.5/3.6

1.VT/VF

2. live discharge

3. ROSC

4. survival to hospital admission

5. survival at 1 year

Age, ALS response interval

3

Weston(1997) [17]

Glamorgan, England (1989–1992)

OHCAs (954)

N/A

N/A

1. admission to hospital

2. discharge from hospital

Age, sex, arrival status, cause of arrest, rhythm of arrest and the delay to ALS

4

Stiell(1999) [30]

Ontario (1991.01–1995.01)

OHCAs (5335)

Mean 68

N/A

1. survival to discharge

Age, bystanders witnessed arrest, fire CPR, EMS response time

5

Holmberg(2000) [18]

Sweden (990.01–1995.05)

OHCAs (9877)

Med 70

N/A

1. 30-day survival

Age, location of arrest, witnessed status, time between call to first ECG

6

Finn(2001) [32]

Perth,Australia (1996–1999)

OHCAs (1293)

VT/VF (286)

Mean65

N/A

1. initial cardiac arrest rhythm of VF/VT in bystander-witnessed cardiac arrests of presumed cardiac origin

2. 28-day survival

Age, gender

7

Herlitz,(2003) [19]

Goteborg, Sweden (1980.10–2000.10)

OHCAs (5505)

N/A

N/A

1. survival to hospital discharge

age, previous history, chronic medication before cardiac arrest, events at resuscitation, and status on admission to hospital

8

Herlitz(2005) [20]

Sweden (1990–2000)

OHCAs (22024)

Mean71 med 73

Med 6

1. survival to 1 month

age, sex, location of arrest, witnessed status, initial cardiac rhythm, EMS response time

9

Iwami(2007) [25]

Osaka, Japan (1998.05–2003.04)

OHCAs (4902)

VT/VF (696)

Mean 62

Mean 9.7

1. neurologically favorable 1-year survival

2. return of spontaneous circulation; admission to hospital; and 1-week, 1-month, and 1-year survival

3. VT/VF

Age, witnessed status, place, defibrillation, EMS response time

10

Herlitz(2008) [34]

Sweden (1990–2005)

OHCAs (22465)

Mean 67

N/A

1. 30-day survival

Age, witnessed status, place, defibrillation, EMS response time

11

Nordberg(2009) [21]

Sweden (1992.01–2005.12)

OHCAs (34125)

Mean 63

Med 7.5

1. 30-day survival

2. VT/VF

Age, sex, witnessed status, initial rhythm, EMS response time

12

Adielsson(2011) [6]

Sweden (1990.01–2009.12)

OHCAs: VT/VF

(7187)

N/A

N/A

1. 30-day survival

2. patients who survived to hospital admission

Age, sex, the site of cardiac arrest, Increasing delay to defibrillation

13

Lindner(2011) [22]

Stavanger, Norway (2001.01–2008.12)

OHCAs (846)

Mean 71

Med 8.5

1. ROSC

2. survival to discharge

age, year, witnessed status, initial cardiac rhythm, EMS response time

14

Wissenberg(2013) [23]

Denmark (2001–2010)

OHCAs (19468)

Med 72

Med 11

1. 30-day survival

age, sex

15

Nehme(2015) [33]

Victoria, Australian (2002.07–2012.06)

OHCAs

VT/VF (5561)

Med 70

Med 8.0

1. survival to hospital discharge

2. survival to hospital discharge (shockable rhythm)

age, sex, year of arrest, witnessed status, initial cardiac rhythm, EMS response time

16

Lai (2015) [26]

Singapore (2001–2004,2010–2012)

OHCAs (5453)

Mean

62

Med 6.2

1. survival to discharge

age, year, witnessed status, initial cardiac rhythm, EMS response time, Mechanical CPR by EMS, prehospital advanced airway, medicine

17

Hasselqvist-Ax(2015) [24]

Sweden (1990.01–2011.12)

OHCAs (30381)

VT/VF (10094)

Med 72

Med 7

1. 30-day survival

2. VT/VF

age, sex, location and cause of cardiac arrest, initial cardiac rhythm, EMS response time, time from collapse to call for EMS, and year of event

18

Gaieski(2017) [31]

Philadelphia (2008–2012)

OHCAs (4625)

Med 64

Med 6.6

1. prehospital ROSC

2. 30-day survival

Age, sex, shockable rhythm, time of arrest, witnessed status, location of cardiac arrest, prehospital AED

19

Tanaka(2017) [27]

Asia (2009.01–2012.12)

OHCAs (56765)

Mean 72.7

Med 76.0

N/A

1. survival to hospital discharge or 30 day hospital survival

2. favorable postarrest cerebral performance

age, bystander-witnessed arrest, shockable rhythm, bystander CPR, out-of-hospital defibrillation, advanced airway and drug administration, and response time