The suggested hedges here are for MEDLINE^®, but the cited papers and the InterTASC Information Specialists Sub-Group Search Filter Resource can be used to find other similar hedges and those for Embase^® and other databases.

Observational studies (Li 2019¹⁰²)

MEDLINE (Ovid)

1. Epidemiologic Studies/
2. exp Case-Control Studies/
3. exp Cohort Studies/
4. Cross-Sectional Studies/
5. (epidemiologic adj (study or studies)).ab,ti.
6. case control.ab,ti.
7. (cohort adj (study or studies)).ab,ti.
8. cross sectional.ab,ti.
9. cohort analy$.ab,ti.
10. (follow up adj (study or studies)).ab,ti.
11. longitudinal.ab,ti.
12. retrospective$.ab,ti.
13. prospective$.ab,ti.
14. (observ$ adj3 (study or studies)).ab,ti.
15. adverse effect?.ab,ti.
16. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15
17. medline.ti.
18. embase.ti.
19. pubmed.ti.
20. (database? and searching).ti.
21. *MEDLINE/
22. *PubMed/
23. *Databases, Bibliographic/
24. 17 or 18 or 19 or 20 or 21 or 22 or 23
25. 16 and 24
26. ((identify$ or develop$ or design$ or test$ or assess$ or evaluat$ or robust$ or optim$ or effic$ or effect$ or sensitiv$ or simpl$ or specific$ or precis$) adj3 ("search strat$" or "search filter?")).ab,ti.
27. 16 and 26
28. 25 or 27

Controlled nonrandomized studies (Waffenschmdt 2020¹⁰³)

MEDLINE (PubMed)

cohort[all] OR (control[all] AND study[all]) OR (control[tw] AND group*[tw]) OR epidemiologic studies[mh] OR program[tw] OR clinical trial[pt] OR comparative stud*[all] OR evaluation studies[all] OR statistics as topic[mh] OR survey*[tw] OR follow-up*[all] OR time factors[all] OR ci[tw]) NOT ((animals[mh:noexp] NOT humans[mh:noexp]) OR comment[pt] OR editorial[pt] OR review[pt] OR meta analysis[pt] OR case report[tw] OR consensus[mh] OR guideline[pt] OR history[sh]

Cohort, case-control, and case series (BMJ¹⁰⁴)

MEDINE (OVID)

1. exp cohort studies/
2. cohort$.tw.
3. controlled clinical trial.pt.
4. epidemiologic methods/
5. limit 4 to yr=1966-1989
6. exp case-control studies/
7. (case$ and control$).tw.
8. (case$ and series).tw.
9. or/1-3,5-8

Adverse events (Golder 2019¹⁰⁵)

MEDLINE (OVID) Medical devices

complicat*.ti,ab. OR ae.fs. [adverse effects] OR safe*.ti,ab. OR exp postoperative complications/OR failure*.ti,ab. OR adverse.ti,ab. OR co.fs. [complications] OR failed.ti,ab. OR exp equipment failure/OR removal.ti,ab. OR equipment safety/OR problem*.ti,ab. OR side effect*.ti,ab. OR harmful.ti,ab. OR tolerated.ti,ab. OR loosen*.ti,ab. OR Intraoperative complications/OR migration.ti,ab. OR breakag*.ti,ab. OR discomfort.ti,ab. OR displacement.ti,ab. OR detrimental adj2 effect*.ti,ab. OR untoward effects.ti,ab.

MEDLINE (OVID) Surgical procedures

complication*.ti,ab. OR ae.fs. [adverse effects] OR safe*.ti,ab. OR co.fs. [complications] OR postoperative complications/

MEDLINE (OVID) Drug interventions

ae.fs. OR co.fs. OR de.fs. OR safe.ti,ab. OR safety.ti,ab. OR side-effect*.ti,ab. OR undesirable effect*.ti,ab. OR treatment emergent.ti,ab. OR tolerability.ti,ab. OR toxicity.ti,ab. OR adrs OR (adverse adj2 (effect OR effects OR reaction OR reactions OR event OR events OR outcome OR outcomes)).ti,ab.