Table 1

Showing characteristics and risk of bias assessment of the included observation studies

Authors
(reference)
No of participants
Design
Place of study
Clinical outcomes reportedCovariates adjusted forNOS *
Statin usersStatin non-usersAdjusted estimate
Gupta et al41296†
Retrospective multicentre cohort study,
USA
In-hospital 30 days mortalityAge, male sex, history of atrial arrhythmias, and DM8/9
96/648 (14.8%)172/648
(26.5%)
OR=0.49
(0.38, 0.63)
Zhang et al54305†
Retrospective multicentre cohort study,
China
MortalityAge, sex, oxygen saturation at admission8/9
45/861
(5.2%)
325/3444
(9.4%)
HR=0.58
(0.43, 0.80)
Alamdari et al6459
Retrospective single centre cohort study,
Iran
MortalityNR6/9
6/117
(5.1%)
57/342
(16.7%)
NR
Daniels et al7170
Retrospective single centre cohort study,
USA
ICU admission or mortalityAge, sex, comorbidities (obesity, HTN,
DM, CVD, and CKD)
7/9
20/46
(43.5%)
70/124
(56.5%)
OR=0.29
(0.11, 0.71)
De Spiegeleer et al8154
Retrospective multicentre cohort study,
Europe
Hospital stay or mortalityAge, sex, functional status, DM, HTN6/9
6/31
(19.4%)
31/123
(25.2%)
OR=0.75
(0.24, 1.87)
Song et al9249
Retrospective single centre cohort study,
USA
MortalityAge, sex, race, CVD, COPD, DM, obesity.7/9
27/123
(21.9%)
15/126
(11.9%)
OR=0.88
(0.37, 2.08)
Yan et al11578
Retrospective multicentre case control
Study, China
Severe and critical diseaseNR5/9
5/15
(33.3%)
123/563
(21.8 %)
NR
McCarthy et al12247
Multi-centre cohort,
USA
ICU admission or mortalityNR5/9
51/107
(47.7%)
61/140
(43.6%)
NR
Krishnan et al13152
Retrospective multicentre cohort study,
USA
MortalityNR5/9
57/81
(70.4%)
35/71
(49.2%)
NR
Rodriguez-Nava et al1987
Retrospective single centre cohort study,
USA
MortalityAge, HTN, CVD, severity, invasive mechanical ventilation, and antibiotics (except azithromycin)6/9
23/47
(48.9%)
25/40
(62.5%)
HR=0.38
(0.18, 0.77)
Nicholson et al201042
Retrospective multicentre cohort study,
USA
MortalityAge, sex, ethnicity, comorbidities, smoking, aspirin, albumin, CRP, PCT and haematological parameters7/9
122/510
(23.9%)
89/530
(16.8%)
OR=0.502
(0.273, 0.926)
Butt et al214842
Observational nationwide cohort study, Denmark
All-cause mortalityAge, sex, ethnicity, socioeconomic status and comorbidities8/9
177/843
(21.0%)
311/3999
(7.8%)
HR=0.96
(0.78, 1.18)
Masana et al222157
Retrospective multicentre cohort study, Spain
MortalityDistance, age, sex, smoking status, comorbidities7/9
115/581
(19.8%)
238/1576
(15.1%)
HR=0.58 §
(0.39, 0.89)
Saeed et al234252
Retrospective single centre cohort study, USA
Cumulative in-hospital mortalityAge, sex, history of AHD, Charlson comorbidity index, presenting vitals, serum glucose, lactic acid, creatinine and intravenous antibiotic use during hospitalisation8/9
311/1355
(23.0%)
782/2897
(27.0%)
HR=0.51
(0.43, 0.61)
  • Clinical outcome data reported as n/N (%).

  • OR/HR presented as ratio (95% CI).

  • *Risk of bias assesssment was performed using NOS.

  • †Number of participants after applying propensity score-matching model to minimise differences in baseline characteristics between statin users versus non-statin users.

  • ‡Studies reporting in-hospital use of statins.

  • §HR calculated 581 statin users and 581 genetic matched statin non-users.

  • ¶HR calculated only for COVID-19 patients with diabetes mellitus (n=2266) with 983 being statin users and 1283 being statin non-users.

  • **

  • AHD, atherosclerotic heart disease; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CRP, C reactive protein; CVD, cardiovascular disease; DM, diabetes mellitus; HTN, hypertension; ICU, intensive care unit; NOS, Newcastle-Ottawa Scale; NR, not reported; OSA, obstructive sleep apnoea; PCT, procalcitonin.