Table 1.

PRISMA checklist.

Section/topic	#	Checklist item	Reported on page #
Title
Title	1	Identify the report as a systematic review, meta-analysis or both.	1
Abstract
Structured summary	2	Provide a structured summary including background, objectives, data sources, study eligibility criteria, participants, interventions, study appraisal and synthesis methods, results, limitations, conclusions and implications of key findings, and a systematic review registration number, as applicable.	2
Introduction
Rationale	3	Describe the rationale for the review in the context of what is already known.	3
Objectives	4	Provide an explicit statement of questions addressed according to participants, interventions, comparisons, outcomes and study design (PICOS).	4
Methods
Protocol and registration	5	Indicate if a review protocol exists, if and where it can be accessed (e.g. Web address) and, if available, provide registration information including a registration number.	N/A
Eligibility criteria	6	Specify the study characteristics (e.g. PICOS, length of follow-up) and report characteristics (e.g. years considered, language, publication status) used as criteria for eligibility and provide a rationale for use.	5
Information sources	7	Describe all the information sources (e.g. databases with dates of coverage, contact with the research authors to identify additional studies) used in the search and the date they were last searched.	5
Search	8	Present a full electronic search strategy for at least one database, including any limits used so that it could be repeated.	5
Study selection	9	State the process for selecting studies (i.e. screening, eligibility, inclusion in the systematic review and, if applicable, inclusion in the meta-analysis).	5
Data collection process	10	Describe the method of data extraction from reports (e.g. piloted forms, independently, in duplicate) and any processes for obtaining and confirming data from investigators.	5
Data items	11	List and define all the variables for which data were sought (e.g. PICOS, funding sources) and any assumptions and simplifications made.	N/A
Risk of bias in individual studies	12	Describe the methods used for assessing individual studies' risk of bias (including specification of whether this was done at the study or outcome level), and how this information is to be used in any data synthesis.	N/A
Summary measures	13	State the principal summary measures (e.g. risk ratio, difference in means).	N/A
Synthesis of results	14	Describe the methods of handling data and combining the results of studies, if this occurred, including measures of consistency (e.g. I2) for each meta-analysis.	N/A
Risk of bias across studies	15	Specify any assessment of risk of bias that may affect the cumulative evidence (e.g. publication bias, selective reporting within studies).	N/A
Additional analyses	16	Describe the methods of additional analyses (e.g. sensitivity or subgroup analysis, meta-regression), if these occurred, indicating which were pre-specified.	N/A
Results
Study selection	17	Provide the numbers of studies screened, assessed for eligibility and included in the review, with reasons for exclusions at each stage ideally with a flow diagram.	6
Study characteristics	18	For each study, present characteristics for which data were extracted (e.g. study size, PICOS, follow-up period) and provide citations.	N/A
Risk of bias within studies	19	Present the data on risk of bias of each study and, if available, any outcome level assessment (see item 12).	N/A
Results of individual studies	20	For all outcomes considered (benefits or harms) and for each study present (a) simple summary data for each intervention group and (b) effect estimates and confidence intervals, ideally with a forest plot.	6–9
Synthesis of results	21	Present results of each meta-analysis done including confidence intervals and measures of consistency.	N/A
Risk of bias across studies	22	Present results of any assessment of risk of bias across studies (see Item 15).	N/A
Additional analysis	23	Provide results of additional analyses, if these occurred (e.g. sensitivity or subgroup analyses, meta-regression [see Item 16]).	N/A
Discussion
Summary of evidence	24	Summarise the main findings including the strength of evidence for each main outcome and consider their relevance to key groups (e.g. healthcare providers, users, policy makers).	10
Limitations	25	Discuss limitations at the study, outcome level (e.g. risk of bias) and review level (e.g. incomplete retrieval of identified research, reporting bias).	10
Conclusions	26	Provide a general interpretation of the results in the context of other evidence and implications for future research.	11
Funding
Funding	27	Describe sources of funding for the systematic review, other support (e.g. supply of data) and the role of funders for the systematic review.	No Funding