Effects of Smoking on COVID-19 Management and Mortality: An Umbrella Review

Table 2

Quality ratings of included studies based on NIH quality assessment (QA) tool for case series studies.

First author (# of ref)	Question									Rating by reviewers
	1	2	3	4	5	6	7	8	9	# 1	# 2
Alghamdi, S.A. [29]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Baker, J [30]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Farsalinos, K [31]	No	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Fair
Gonzalez-Rubio, J [32]	No	Yes	N/A	Yes	N/A	No	N/A	No	Yes	Fair	Poor
Grundy, E. J [33]	Yes	Yes	N/A	Yes	N/A	No	N/A	No	Yes	Fair	Fair
Gulsen, A [34]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Hou, H [35]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Kang, S [36]	No	No	N/A	Yes	N/A	No	N/A	Yes	Yes	Fair	Fair
Karanasos, A [27]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Kumar, R [37]	Yes	No	N/A	Yes	N/A	Yes	N/A	No	Yes	Fair	Good
Li, J [38]	No	Yes	N/A	No	N/A	No	N/A	Yes	No	Poor	Poor
Luo, S [39]	Yes	Yes	N/A	Yes	N/A	No	N/A	No	No	Fair	Poor
Mahamat-Saleh, Y [40]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	No	Yes	Good	Good
Mattey-Mora, PP [41]	No	Yes	N/A	Yes	N/A	No	N/A	No	No	Poor	Fair
Mesas, AE [42]	Yes	Yes	N/A	Yes	N/A	No	N/A	Yes	Yes	Fair	Good
Minh, LHN [43]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Patanavanich, R [44]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Patanavanich, R [45]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Plasencia-Urizarri, TM [46]	Yes	No	N/A	Yes	N/A	Yes	N/A	Yes	No	Fair	Poor
Pranata, R [47]	Yes	No	N/A	Yes	N/A	No	N/A	Yes	Yes	Good	Good
Reddy, RK [28]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Sanchez-Ramirez, DC [48]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Taylor, EH [49]	No	Yes	N/A	Yes	N/A	No	N/A	Yes	Yes	Good	Fair
Umnuaypornlert, A [50]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Vardavas, C.I [18]	No	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Zhang, H [51]	Yes	Yes	N/A	Yes	N/A	Yes	N/A	Yes	Yes	Good	Good
Zhang, T [52]	No	Yes	N/A	Yes	N/A	No	N/A	Yes	Yes	Fair	Good

Note: NIH: National Institutes of Health; CD: cannot determine; NR: not reported; NA: not applicable. The NIH quality assessment tool for case series studies (https://www.nhlbi.nih.gov/health-topics/study-quality-assessment-tools) contains nine questions: 1 = Was the study question or objective clearly stated?, 2 = Was the study population clearly and fully described, including a case definition?, 3 = Were the cases consecutive?, 4 = Were the subjects comparable?, 5 = Was the intervention clearly described?, 6 = Were the outcome measures clearly defined, valid, reliable, and implemented consistently across all study participants?, 7 = Was the length of follow-up adequate?, 8 = Were the statistical methods well-described?, 9 = Were the results well-described? (source: National Heart, Lung, and Blood Institute; National Institutes of Health; U.S. Department of Health and Human Services) https://www.nhlbi.nih.gov/health-topics/study-quality-assessment-tools.