Table 2

Summary of study time periods

StudyCOVID-19 period startComparison period startCOVID-19 period endComparison period endCOVID-19 period length (days)Comparison period length (days)
Aboul-Nour 202118 3/20/203/20/195/20/205/20/196161
Agarwal 202019 3/1/206/1/195/15/202/29/2075273
Altschul 20208 3/1/201/1/204/17/202/17/204747
Amukotuwa 202011 3/1/201/31/195/10/203/1/197029
Aref 202120 2/15/2012/7/195/10/202/14/208569
Candelaresi 202121 3/9/203/9/194/16/204/16/193838
Chen 202122 1/1/201/1/189/30/2012/31/19273729
Cummings 202023 3/1/203/1/194/1/202/1/2031337
D'Anna 202124 3/23/203/23/196/30/206/30/199999
Ghoreishi 202025 2/18/202/18/197/18/207/18/19151150
Gu 202126 2/1/2012/1/193/31/201/30/205960
Huo 202127 1/1/201/1/194/30/204/30/19120119
Jasne 202028 3/1/202/1/204/28/204/28/205887
John 202016 3/1/203/1/195/10/205/10/197070
Katsanos 202029 3/17/203/1/194/30/203/16/2044381
Kwan 202030 3/3/201/1/204/30/203/3/205862
Li 202131 1/23/202/3/204/8/204/17/207674
Luo 202132 1/1/201/1/195/31/205/31/19151150
Mag Uidhir 202033 1/1/201/1/196/30/206/30/19181180
Mitra 202034 3/26/203/26/194/23/204/23/192828
Naccarato 202035 3/9/203/9/194/9/204/9/193131
Nagamine 20209 3/1/203/1/194/30/204/3/196033
Neves-Briard 202017 3/30/203/30/195/31/205/31/196262
Padmanabhan 202036 3/15/203/15/194/14/204/14/193030
Paliwal 202037 2/7/2011/1/194/30/202/6/208397
Plumereau 202038 2/29/202/28/195/10/205/10/197171
Rinkel 202039 3/16/2010/21/195/3/2012/8/194848
Rudilosso 202040 3/1/203/1/193/31/203/31/193030
Siegler 202041 3/1/2010/1/194/15/202/29/2045151
Tan 202142 1/24/201/24/193/10/203/10/194645
Tejada-Meza 202043 3/9/2012/30/195/3/203/8/205569
Teo 202010 1/23/201/23/193/24/203/24/196160
Uchino 202044 3/9/201/1/204/2/203/8/202467
Velilla-Alonso 202145 3/14/203/14/195/14/205/14/196161
Wang 202046 3/12/2012/1/196/30/203/11/20110101
Yang 202047 1/23/2012/1/193/7/201/14/204444
Zhang 202148 1/23/2011/8/194/8/201/22/207675
Zini 202049 3/1/203/1/194/30/204/30/196060
  • The COVID-19 and comparison period dates for each study are presented. The COVID-19 period was defined as the period of time occurring after the pandemic began, and the comparison period before the pandemic began. The length of each period in days for each study are also presented.