Appendix 4Quality assessment tools
Quality assessment tool for observational/cross-sectional studies
Was the research question clearly stated?
Was the study population clearly specified and defined?
Was the participation rate of eligible persons at least 50%?
Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria prespecified and applied uniformly to all participants?
Was a sample size justification, power description, or variance and effect estimate provided?
For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome?
Were the exposure measures (independent variables) clearly defined, valid, reliable and implemented consistently across all study participants?
Were the outcome measures (dependent variables) clearly defined, valid, reliable and implemented consistently across all study participants?
Were the outcome assessors blinded to the exposure status of participants?
Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)?
Quality assessment tool for diagnostic studies
Was the spectrum of patients representative of the patients who will receive the test in practice? (Representative spectrum.)
Is the reference standard likely to classify the target condition correctly? (Acceptable reference standard.)
Is the time period between reference standard and index test short enough to be reasonably sure that the target condition did not change between the two tests? (Acceptable delay between tests.)
Did the whole sample or a random selection of the sample receive verification using the intended reference standard? (Partial verification avoided.)
Did patients receive the same reference standard irrespective of the index test result? (Differential verification avoided.)
Was the reference standard independent of the index test (i.e. the index test did not form part of the reference standard)? (Incorporation avoided.)
Were the reference standard results interpreted without knowledge of the results of the index test? (Index test results blinded.)
Were the index test results interpreted without knowledge of the results of the reference standard? (Reference standard results blinded.)
Were the same clinical data available when test results were interpreted as would be available when the test is used in practice? (Relevant clinical information.)
Were uninterpretable/intermediate test results reported? (Uninterpretable results reported.)
Were withdrawals from the study explained? (Withdrawals explained.)
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