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Table 8 STROBE Statement—Checklist of items that should be included in reports of case-control studies

From: Association of serum uric acid levels with COVID-19 severity

  Item No Recommendation Page No
Title and abstract 1 (a) Indicate the study’s design with a commonly used term in the title or the abstract 1
(b) Provide in the abstract an informative and balanced summary of what was done and what was found 5–7
 Background/rationale 2 Explain the scientific background and rationale for the investigation being reported 8–9
 Objectives 3 State specific objectives, including any prespecified hypotheses 9–10
 Study design 4 Present key elements of study design early in the paper 10–12
 Setting 5 Describe the setting, locations, and relevant dates, including periods of recruitment, exposure, follow-up, and data collection 10–12
 Participants 6 (a) Give the eligibility criteria, and the sources and methods of case ascertainment and control selection. Give the rationale for the choice of cases and controls 10–11
(b) For matched studies, give matching criteria and the number of controls per case 10–11
 Variables 7 Clearly define all outcomes, exposures, predictors, potential confounders, and effect modifiers. Give diagnostic criteria, if applicable 10–12
 Data sources/ measurement 8* For each variable of interest, give sources of data and details of methods of assessment (measurement). Describe comparability of assessment methods if there is more than one group 10–12
 Bias 9 Describe any efforts to address potential sources of bias 10–12
 Study size 10 Explain how the study size was arrived at 10–11
 Quantitative variables 11 Explain how quantitative variables were handled in the analyses. If applicable, describe which groupings were chosen and why 11–12
 Statistical methods 12 (a) Describe all statistical methods, including those used to control for confounding 12–13
(b) Describe any methods used to examine subgroups and interactions 12–13
(c) Explain how missing data were addressed 10
(d) If applicable, explain how matching of cases and controls was addressed 10–11
(e) Describe any sensitivity analyses 12–13
 Participants 13* (a) Report numbers of individuals at each stage of study—eg numbers potentially eligible, examined for eligibility, confirmed eligible, included in the study, completing follow-up, and analysed 13–14
(b) Give reasons for non-participation at each stage
(c) Consider use of a flow diagram 14
 Descriptive data 14* (a) Give characteristics of study participants (eg demographic, clinical, social) and information on exposures and potential confounders 13–14
(b) Indicate number of participants with missing data for each variable of interest
 Outcome data 15* Report numbers in each exposure category, or summary measures of exposure 14–17
 Main results 16 (a) Give unadjusted estimates and, if applicable, confounder-adjusted estimates and their precision (eg, 95% confidence interval). Make clear which confounders were adjusted for and why they were included 14–17
(b) Report category boundaries when continuous variables were categorized 14–17
(c) If relevant, consider translating estimates of relative risk into absolute risk for a meaningful time period 14–17
 Other analyses 17 Report other analyses done—eg analyses of subgroups and interactions, and sensitivity analyses
 Key results 18 Summarise key results with reference to study objectives 18–21
 Limitations 19 Discuss limitations of the study, taking into account sources of potential bias or imprecision. Discuss both direction and magnitude of any potential bias 22–23
 Interpretation 20 Give a cautious overall interpretation of results considering objectives, limitations, multiplicity of analyses, results from similar studies, and other relevant evidence 21–22
 Generalisability 21 Discuss the generalisability (external validity) of the study results 21–22
Other information
 Funding 22 Give the source of funding and the role of the funders for the present study and, if applicable, for the original study on which the present article is based 23