Methodological quality and redundancy of systematic reviews that compare endarterectomy versus stenting for carotid stenosis

A review of systematic reviews (SRs) and a critical appraisal study was conducted at Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp). The objectives of this review are (1) to identify all published SRs comparing the effectiveness and safety of carotid endarterectomy (CEA) versus carotid artery stenting (CAS) for carotid artery stenosis, (2) to assess their methodological quality and (3) to compare the primary studies contained in each SR. We included 17 SRs published between 2005 and 2017. None of the SRs fulfilled all items of AMSTAR-2. The overall confidence in the results was graded as critically low for 16 SRs (94%) and low for 1 SR (6%). Five items were judged inadequate in all SRs: reference to a published protocol, explanation to the selection of study design, comprehensive search of the literature, methods for statistical combination of findings and consideration of the risk of bias on the results of meta-analysis. In total, 15 randomised clinical trials (RCTs) were included at least in one SR. The number of included RCTs in each SR was inconsistent (4 to 15) and was not related to the year of publication of the SR. Our study found redundant and low methodological quality SR comparing CAS versus CEA for carotid stenosis.