Table 1

Reporting elements (REs) and quality assessment attributes (QAAs) according to selected domains and percent representation among reviewed tools

Reporting elements (REs)Percent representation (%)Quality assessment attributes (QAAs)Percent representation (%)
A. Research aims6934
 RE 1: Description of study objectives, research aims, design, study population and data source, exposure and outcome69QAA 1: Appropriateness of prespecified aims, design, population, exposure and outcome to address research aim34
B. Study population: data sources8457
 RE 1: Description of participation rates and discontinuation rates77QAA 1: Extent of participation rates and discontinuation rates56
 RE 2: Description of denominator used for risk assessment11QAA 2: Appropriateness of denominator used for risk assessment3
C. Exposure definition and ascertainment6131
 RE 1: Description of operational aspects of exposure ascertainment and definition49QAA 1: Validity and appropriateness of operational aspects used to ascertain and define exposure status30
 RE 2: Description of blinding of outcome status21
 RE 3: Selection of exposure risk window5QAA 2: Appropriateness of selected exposure risk window3
 RE 4: Description of selected type of users (incident vs prevalent users)0QAA 3: Appropriateness of selected numerator for risk assessment0
 RE 5: Description of comparison group10QAA 4: Appropriateness of comparison group5
D. Safety outcome definition and ascertainment6936
 RE 1: Description of operational aspects of outcome ascertainment and definition51QAA 1: Appropriateness/validity of outcome ascertainment strategies and outcome definition33
 RE 2: Description of blinding of exposure status from those ascertaining/validating outcomes25
 RE 3: Description of follow-up time16QAA 2: Adequacy of follow-up time to address research question13
 RE 4: Description of composite outcome, if relevant0QAA 3: Adequacy of composite safety outcome, if relevant0
E. Analytical approach8549
 RE 1: Description of analytic approach, including approaches to handle confounding and biases80QAA 1: Appropriateness of described analytic approach26
 RE 2: Description of a priori sample size/power calculations44QAA 2: Appropriateness of approaches to handle confounding and biases39
 RE 3: Description of data integration methods, when relevant3QAA 3: Description of a priori sample size/power calculations21
 RE 4: Description of measures of frequency and association7QAA 4: Appropriateness of data integration methods, when relevant0
 RE 5: Description of a priori specifications of subgroup analyses5
F. Results367
 RE 1: Description of main results (unadjusted and adjusted estimates and confidence intervals) and sensitivity analyses25QAA 1: Consistency of primary, secondary and sensitivity analyses and consistency of confounding effects with known associations2
 RE 2: Description of patient disposition15QAA 2: Impact of patient disposition on study integrity and generalisability of findings6
 RE 3: Description of characteristics of population by comparison group18
G. Discussion and interpretation3620
 RE 1: Description of findings in relation to pertinent issues related to study design, conduct, limitations and power28QAA 1: Consideration of findings in relation to pertinent issues related to study design, conduct, limitations and power18
 RE 2: Description of plausibility of findings and clinical significance and discussion/exploration of alternative explanations, comparison with other findings21QAA 2: Discussion of plausibility of findings and clinical significance and discussion of alternative explanations, comparison with other findings11
H. Study team73
 RE 1: Description of study team, conflict of interest, funding sources7QAA 1: Relevance of study team credentials and experience to the research area0
QAA 2: Independence of study team and funding sources3