For the present analysis, reviews on NPWT were classified as eligible systematic reviews if multiple sources were systematically searched and the search strategy was documented.
Five databases were systematically searched.
MEDLINE, EMBASE, CENTRAL/CCTR, Clinicaltrials.gov and ICTRP were systematically searched.
Electronic databases were systematically searched before February 2013.
PubMed, Web of Science and Cochrane databases were systematically searched to identify all relevant studies.
Medline, PsycINFO and the Cochrane Library were systematically searched for articles published until February 2015.
Electronic databases were systematically searched for studies published until October 2015.
Six databases were systematically searched from inception until 4th July 2016.
Studies published up to April 2015 about the association between CDH and BMI were systematically searched from multiple electronic databases.
Three electronic databases (MEDLINE, PsycINFO and PubMed) were systematically searched for studies published from January 1980 to June 2014.
PubMed, PsychINFO, Web of Science, Sociological Abstracts, and CINAHL were systematically searched and expanded by hand search.
