Table 3.

Modified GRADE ratings for each study and the overall rating of strength of evidence.

Reference	Unified Statistical Analysis	Confounders Used	Outcomes of Interest Pre-Specified	Consistency of Results	Little Likelihood of Publication Bias	Large Sample	Certainty Evidence Rating
Alonso et al. (2013) [38]	1	1	1	1	1	1	High
Anil Kumar & Mattoo (2015) [39]	1	1	1	1	1	1	High
Bailey et al. (2021) [40]	1	0	1	1	1	1	Moderate
Burra et al. [12]	1	0	1	1	1	1	Moderate
Coilly et al. (2015) [41]	1	1	1	1	1	0	Moderate
Hammond et al. (2021) [42]	1	1	1	1	1	1	High
Jones & Serper (2020) [13]	1	1	1	1	1	0	Moderate
Kaplan et al. (2023) [14]	1	1	1	1	1	0	Moderate
Ko et al. (2018) [43]	1	0	1	1	1	1	Moderate
Meng et al. (2019) [44]	1	1	1	1	1	1	High
Oliveira et al. (2016) [25]	1	1	1	1	0	1	Moderate

Note: 1 if the criteria is fulfilled; 0 otherwise.