Table 2 The search terms for each academic database

Euthanasia

Euthanasia[MAJR:NOEXP] OR Euthanasia, active[MAJR:NOEXP] OR Euthanasia, Active, Voluntary[MAJR] OR Suicide, assisted[MAJR] OR Deep sedation[MAJR] OR Euthanasia*[TI] OR Assisted suicide*[TI] OR Assisted death*[TI] OR Assisted dying[TI] OR "Aid in dying" [TI] OR "Termination of life"[TI] OR Shorten life[TI] or Shortens life[TI] or Life Shorten*[TI] or Mercy killing[TI] OR ("End of life"[TI] AND (Decision*[TI] OR Practice*[TI])) OR Lethal drug*[TI] OR Deep sedation[TI] OR Continuous sedation[TI] OR Terminal sedation[TI]

*Euthanasia/or *Active euthanasia/or *Voluntary euthanasia/OR *Assisted suicide/OR *Deep sedation/or (Euthanasia? OR (Assisted adj2 (Suicide? OR Death? OR Dying)) or "Aid in dying" OR ((Termination or Shorten*) adj2 Life) or Mercy killing OR ("End of life" adj2 (Decision? OR Practice?)) OR Lethal drug? OR ((Deep or Continuous or Terminal) adj2 Sedation)).ti

*Euthanasia/or *Assisted Suicide/or (Euthanasia? OR (Assisted adj2 (Suicide? OR Death? OR Dying)) or "Aid in dying" OR ((Termination or Shorten*) adj2 Life) or Mercy killing OR ("End of life" adj2 (Decision? OR Practice?)) OR Lethal drug? OR ((Deep or Continuous or Terminal) adj2 Sedation)).ti

TI = (Euthanasia* OR (Assisted NEAR/2 (Suicide? OR Death? OR Dying)) OR "Aid in dying" OR "Mercy killing" OR (Life NEAR/2 (Shorten* or Termination)) OR ("End of life" NEAR/2 (Decision? OR Practice?)) OR "Lethal drug*" OR (Sedation NEAR/2 (Deep OR Continuous OR Terminal)))

MM "Euthanasia" OR MM "Suicide, Assisted" OR TI (Euthanasia* OR (Assisted N2 (Suicide? OR Death? OR Dying)) OR "Aid in dying" OR "Mercy killing" OR (Life N2 (Shorten* or Termination)) OR ("End of life" N2 (Decision? OR Practice?)) OR "Lethal drug*" OR (Sedation N2 (Deep OR Continuous OR Terminal)))

TI,SU(Euthanasia* OR (Assisted NEAR/2 (Suicide* OR Death* OR Dying)) OR "Aid in dying" OR "Mercy killing" OR (Life NEAR/2 (Shorten* or Termination)) OR ("End of life" NEAR/2 (Decision* OR Practice*)) OR "Lethal drug*" OR (Sedation NEAR/2 (Deep OR Continuous OR Terminal)))

TI,SU(Euthanasia* OR (Assisted NEAR/2 (Suicide* OR Death* OR Dying)) OR "Aid in dying" OR "Mercy killing" OR (Life NEAR/2 (Shorten* or Termination)) OR ("End of life" NEAR/2 (Decision* OR Practice*)) OR "Lethal drug*" OR (Sedation NEAR/2 (Deep OR Continuous OR Terminal)))

TI,AB,SU(Euthanasia* OR (Assisted NEAR/2 (Suicide* OR Death* OR Dying)) OR "Aid in dying" OR "Mercy killing" OR (Life NEAR/2 (Shorten* or Termination)) OR ("End of life" NEAR/2 (Decision* OR Practice*)) OR "Lethal drug*" OR (Sedation NEAR/2 (Deep OR Continuous OR Terminal)))

TI,AB,SU(Euthanasia* OR (Assisted NEAR/2 (Suicide* OR Death* OR Dying)) OR "Aid in dying" OR "Mercy killing" OR (Life NEAR/2 (Shorten* or Termination)) OR ("End of life" NEAR/2 (Decision* OR Practice*)) OR "Lethal drug*" OR (Sedation NEAR/2 (Deep OR Continuous OR Terminal)))

Systematic review

Meta-analysis[PT] or ((Review[PT] or Review[TI]) AND (PubMed[TIAB] or Medline[TIAB] or Embase[TIAB] or CINAHL[TIAB] or PsycInfo[TIAB])) or Cochrane Database Syst Rev[TA] or Meta-Analysis[TI] or Metaanalys*[TI] or Systematic[TI]

Meta analysis/OR Systematic review/or ((Review/or Review.ti) AND (PubMed or Medline or Embase or CINAHL or PsycInfo).ab) or Cochrane.jw or (Meta-Analysis or Metaanalys* or Systematic).ti

(Meta analysis or Systematic review).id,md or ((Literature review/or Literature Review.id,md or Review.ti) AND (PubMed or Medline or Embase or CINAHL).ab) or Cochrane.jw or (Meta-Analysis or Metaanalys* or Systematic).ti

TS = (PubMed or Medline or Embase or CINAHL or PsycInfo) AND DOCUMENT TYPES: (Review) OR TI = ("Meta Analysis" OR Systematic OR Metaanalys*)

MH "Meta-Analysis" or MH "Systematic review" OR PT Systematic review or ((PT Review or TI Review) AND AB (PubMed or Medline or Embase or CINAHL or PsycInfo)) or JT Cochrane or TI (Meta-Analysis or Metaanalys* or Systematic)

Empirical studies

Comparative study[PT] or Observational Study[PT] OR Cohort studies[MH] OR Cross-Sectional Studies[MH] OR Cross Cultural Comparison[MH] or Anthropology, Cultural[MH:NOEXP] OR Empirical research[MH] OR "Interviews as Topic"[MH] OR Questionnaires[MH] OR "Physician's Practice Patterns"[MH] OR "Statistics and numerical data"[SH] OR Trends[SH] OR "Before and after"[TI] OR Cohort[TI] OR Comparison[TI] OR Comparative[TI] OR Cross sectional[TI] OR Cultural anthropolog*[TI] OR Descriptive[TI] OR Empirical[TI] OR Ethnograph*[TI] OR Focus group*[TI] OR Follow back[TI] OR Follow up[TI] OR Interview*[TI] OR Longitudinal[TI] OR Observational[TI] OR Population based[TI] OR Qualitative[TI] OR Questionnaire*[TI] OR Prospective[TI] OR Retrospective[TI] OR Survey[TI] OR Surveys[TI] OR Trend[TI] OR Trends[TI]

Comparative study/or Observational study/or Cohort analysis/or Longitudinal study/or Prospective study/OR Retrospective study/or Cross-sectional study/or Cultural anthropology/or Ethnography/or Empirical Research/or Exp Interview/or Qualitative research/or Exp Questionnaire/or Clinical practice/or Trend study/or ("Before and after" OR Cohort OR Comparison OR Comparative OR Cross sectional OR Cultural anthropolog* OR Descriptive OR Empirical OR Ethnograph* OR Focus group? OR Follow back OR Follow up OR Interview? OR Longitudinal OR Observational OR Population based OR Qualitative OR Questionnaire? OR Prospective OR Retrospective OR Survey? OR Trend?).ti

(Empirical study or Focus group or Followup study or Interview or Longitudinal study or Prospective study or Qualitative study or Quantitative study or Retrospective study).md or Cross Cultural Differences/or "Culture (Anthropological)"/or Ethnography/or Questionnaires/or Exp Surveys/or Clinical practice/or Trends/

TS = ("Before and after" OR Cohort OR "Cross sectional" OR "Cultural anthropolog*" OR Empirical OR Ethnograph* OR "Focus group?" OR "Follow back" OR "Follow up" OR Interview? OR Longitudinal OR Observational OR "Population based" OR Qualitative OR Questionnaire? OR Prospective OR Retrospective OR Survey? OR Trend?) or TI = (Comparison OR Comparative OR Descriptive)

MH "Comparative studies" OR MH "Cross Sectional Studies" OR MH "Prospective studies + " OR MH "Retrospective design" OR MH "Questionnaires + " OR MH "Empirical Research" OR MH "Qualitative Studies + " OR MH "Focus groups" or MH Interviews + OR MH "Quantitative Studies" OR MH "Quasi-Experimental Studies + " OR TI ("Before and after" OR Cohort OR Comparison OR Comparative OR Cross sectional OR Cultural anthropolog* OR Descriptive OR Empirical OR Ethnograph* OR Focus group? OR Follow back OR Follow up OR Interview? OR Longitudinal OR Observational OR Population based OR Qualitative OR Questionnaire? OR Prospective OR Retrospective OR Survey? OR Trend?)