Table 1.
Characteristics of Included Studies
| Study | Location | Study Designa | Study Population | Time Period (i) Pre-COVID-19 (ii) COVID-19 |
Sample Size (i) Pre-COVID-19 (ii) COVID-19 |
|---|---|---|---|---|---|
| Baert et al. 2020 [25] | France | Registry-based study | Adult and pediatric cases of presumed medical etiology (EMS-treated NR; Received resuscitation NR) |
(i) March 1–April 31, 2019 (ii) March 1–April 31, 2020 |
(i) 1620 (ii) 1005 |
| Baldi et al. 2020 [26] | Lombardy, Italy | Registry-based study | Adult and pediatric cases regardless of etiology (EMS-treated NR; Received resuscitation NR) |
(i) February 21–April 20, 2019 (ii) February 21–April 20, 2020 |
(i) 321 (ii) 490 |
| Ball et al. 2020 [7] | Victoria, Australia | Registry-based study | Adult cases regardless of etiology; EMS-treated and received resuscitation |
(i) March 16–May 12, 2017–2019 (ii) March 16–May 12, 2020 |
(i) 1218 (ii) 380 |
| Cho et al. 2020 [27] | Daegu, South Korea | Registry-based study | Adult cases of presumed medical etiology; EMS-treated and received resuscitation |
(i) February 17–March 31, 2018 (ii) February 17–March 31, 2020 |
(i) 158 (ii) 171 |
| Elmer et al. 2020 [28] | Pennsylvania, USA | Registry-based study | Adult cases regardless of etiology; EMS-treated (Received resuscitation NR§) |
(i) January–February 2016–2020 (ii) March 1–May 25, 2020 |
(i) 12,252 (ii) 683 |
| Lai et al. 2020 [29] | New York City, USA | Non-registry-based study | Adult cases regardless of etiology; EMS-treated and received resuscitation |
(i) March 1–April 25, 2019 (ii) March 1–April 25, 2020 |
(i) 1336 (ii) 3989 |
| Marijon et al. 2020 [6] | Paris, France | Registry-based study | Adult cases of non-traumatic etiology; EMS-treated (Received resuscitation NR) |
(i) Weeks 12–17, 2012–2019 (ii) March 16–April 26, 2020 |
(i) 3052 (ii) 521 |
| Ortiz et al. 2020 [30] | Spain | Registry-based study | Adult and pediatric cases regardless of etiology; EMS-treated (Received resuscitation NR) |
(i) April 1–30, 2017 and February 1–March 31, 2018 (ii) February 1–April 30, 2020 |
(i) 1723 (ii) 1446 |
| Paoli et al. 2020 [31] | Province of Padua, Italy | Non-registry-based study | Adult and pediatric cases regardless of etiology; EMS-treated (Received resuscitation NR§) |
(i) March 1–April 30, 2019 (ii) March 1–April 30, 2020 |
(i) 206 (ii) 200 |
| Sayre et al. 2020 [32] | Seattle and King County, USA | Registry-based study | Adult and pediatric cases regardless of etiology; EMS-treated (Received resuscitation NR§) |
(i) January 1–February 25, 2019 (ii) February 26–April 15, 2020 |
(i) 530 (ii) 537 |
| Semeraro et al. 2020 [33] | Bologna, Italy | Registry-based study | Adult cases regardless of etiology; EMS-treated and received resuscitation |
(i) January 1–June 30, 2019 (ii) January 1–June 30, 2020 |
(i) 563 (ii) 624 |
| Chan et al. 2021 [34] | 27 States and multiple Counties, USA | Registry-based study | Adult cases of non-traumatic etiology; EMS-treated (Received resuscitation NR) |
(i) March 16–April 30, 2019 (ii) March 16–April 30, 2020 |
(i) 9440 (ii) 9863 |
| de Koning et al. 2021 [35] | Hollands-Midden, The Netherlands | Registry-based study | Adult cases regardless of etiology; EMS-treated (Received resuscitation NR) |
(i) March 16–April 27, 2019 (ii) March 16–April 27, 2020 |
(i) 45 (ii) 56 |
| Fothergill et al. 2021 [8] | London, UK | Registry-based study | Adult and pediatric cases regardless of etiology; EMS*-treated (Received resuscitation NR§) |
(i) March 1–April 30, 2019 (ii) March 1–April 30, 2020 |
(i) 1724 (ii) 3122 |
| Glober et al. 2021 [36] | Indiana (Marion County), USA | Registry-based study | Adult cases of non-traumatic etiology; EMS-treated (Received resuscitation NR) |
(i) January 1–June 30, 2019 (ii) January 1–June 30, 2020 |
(i) 884 (ii) 1034 |
| Lim et al. 2021 [37] | Singapore | Registry-based study | Adult cases regardless of etiology; EMS-treated (Received resuscitation NR) |
(i) January 1–May 31, 2018–2019 (ii) January 1–May 31, 2020 |
(i) 1280 (ii) 1400 |
| Mathew et al. 2021 [38] | Detroit, USA | Registry-based study | Adult cases of non-traumatic etiology; EMS-treated and received resuscitation |
(i) March 10–April 30, 2019 (ii) March 10–April 30, 2020 |
(i) 180 (ii) 291 |
| Nickles et al. 2021 [39] | Detroit (Macomb, Oakland, and Wayne Counties), USA | Registry-based study | Adult and pediatric cases of non-traumatic etiology; EMS-treated (Received resuscitation NR) |
(i) January 1–May 31, 2019 (ii) January 1–May 31, 2020 |
(i) 1162 (ii) 1854 |
| Sultanian et al. 2021 [40] | Sweden | Registry-based study | Adult and pediatric cases regardless of etiology; EMS-treated and received resuscitation |
(i) January 1–March 16, 2020 (ii) March 16–July 20, 2020 |
(i) 930 (ii) 1016 |
| Uy-Evanado et al. 2021 [41] | Oregon (Multnomah County) and California (Ventura County), USA | Registry-based study | Adult and pediatric cases regardless of etiology; EMS-treated and received resuscitation |
(i) March 1–May 31, 2019 (ii) March 1–May 31, 2020 |
(i) 231 (ii) 278 |
EMS Emergency Medical Services, UK United Kingdom, USA United States of America, NR Not Reported, COVID-19 coronavirus disease 2019
aStudy designs for all included studies were multicentered and retrospective in nature