Table 1.
Characteristics of included systematic reviews of diagnostic accuracy
| Non‐Cochrane systematic reviews (n = 100) | Cochrane systematic reviews (n = 100) | |
|---|---|---|
| General characteristics and efforts to identify studies | ||
| Number of authors, median (IQR) | 5 (4–7) | 7 (6‐8) |
| Type of index test | ||
| Imaging test | 60 | 34 |
| Laboratory test | 27 | 33 |
| Other type of test | 9 | 26 |
| Multiple types of tests | 4 | 7 |
| Language restrictions | ||
| No | 37 | 90 |
| Yes | 56 | 6 |
| Not reported | 7 | 4 |
| Authors contacted for additional data, if needed | ||
| Yes | 31 | 78 |
| No or not reported | 69 | 22 |
| At least some requested data obtained after contacting authors | ||
| Yes | 8 | 52 |
| No or not reported | 23 | 26 |
| Number of bibliographic databases searched, median (IQR) | 4 (3–5) | 6 (5–9) |
| MEDLINE/PubMed | 100 | 100 |
| EMBASE | 81 | 100 |
| Cochrane Library (including CENTRAL, DARE and/or HTA) | 68 | 71 |
| Web of Science (including CPCI and/or SCI) | 42 | 65 |
| LILACS | 13 | 39 |
| BIOSIS (including BIOSIS Previews and/or BIOSIS Citation Index) | 4 | 36 |
| CINAHL | 11 | 33 |
| PsychINFO | 3 | 27 |
| SCOPUS | 21 | 7 |
| African Index Medicus | 2 | 4 |
| Other | 40 | 85 |
| Unpublished studies eligible for inclusion | ||
| (At least one type of) unpublished studies explicitly eligible | 10 | 42 |
| (At least one type of) unpublished studies explicitly not eligible | 36 | 10 |
| Not reported (although some did explicitly search sources of unpublished studies) | 54 | 48 |
| Additional efforts to identify (published or unpublished) studies | ||
| At least one additional effort made | 76 | 98 |
| Screening of reference lists of included studies | 71 | 96 |
| Searching of relevant review articles or clinical guidelines | 18 | 52 |
| Screening of articles citing included studies | 3 | 42 |
| Contacting authors or experts | 6 | 37 |
| Using a “related articles” search feature | 6 | 32 |
| Contacting device manufacturers | 0 | 9 |
| Other | 4 | 11 |
| Specific sources of unpublished studies searched | ||
| At least one specific source searched | 22 | 68 |
| Sources of conference abstracts searched | 6 | 45 |
| Conference proceedings of specific conferences | 4 | 18 |
| Databases only containing conference abstracts (ie, CPCI and/or British Library Zetoc conference search) | 2 | 33 |
| Trial registries searched | 12 | 39 |
| ClinicalTrials.gov | 7 | 33 |
| WHO ICTRP | 6 | 32 |
| ISRCTN | 1 | 12 |
| Other | 1 | 3 |
| Other (ie, specific sources of theses, dissertations, studies in‐progress, or other grey literature) | 10 | 15 |
| ProQuest Dissertations and Theses | 3 | 6 |
| OpenGREY | 6 | 4 |
| Other | 4 | 7 |
| Systematic review results | ||
| Total number of studies included, median (IQR) | 14.5 (10–23) | 15.5 (8–41) |
| At least one unpublished study included in systematic review | 17 | 23 |
| At least one meta‐analysis performed | 89 | 71 |
| At least one unpublished study included in at least one meta‐analysis | 14 | 18 |
| Comparison between published and unpublished studies (or a sensitivity analysis excluding unpublished studies) planned | 1 | 11 |
| Comparison between published and unpublished studies (or a sensitivity analysis excluding unpublished studies) performed | 1 | 2 |
Note: Data are absolute numbers, unless otherwise indicated.
Abbreviation: IQR, inter quartile range.