Probiotics As Adjunctive Therapy For Helicobacter Pylori Infection：an Overview Of Systematic Reviews And Meta-analyses

Objective: To evaluate the relevant systematic reviews/Meta-analyses(SRs/MAs) that focused on probiotics as adjunctive therapy for Helicobacter pylori(H. pylori) infection.Methods: The SRs/MAs on probiotics as adjunctive therapy for H. pylori infection were searched in Pub Med、Embase 、The Cochrane library、Chinese Biomedical Literature Database(CBM)、China National Knowledge Infrastructure(CNKI)、Wanfang database and VIP database from inception to October, 2014. Two reviewers screened the literature according to the inclusion criteria and extracted the data. The methodological quality of included studies was assessed by using AMSTAR scale, then Preferred reporting items for SR and MA(PRISMA) was used to evaluate the reporting quality of included studies, and Grade of Recommendation, Assessment, Development, and Evaluation(GRADE) system was used to evaluate the quality of evidence for the outcomes of included studies.Results: A total of eleven relevant SRs/MAs were included, which all evaluated the H.pylori eradication and incidence rate of total side effects, of which three evaluated the Anti-H. pylori therapy-related side effects in detail. Ten of them assessed the methodological quality of included original randomized controlled trials(RCTs) with different tools: 5 used Jadad scale, 5 used Cochrane bias risk assessment tool.The result of methodological quality showed that: the AMSTAR score of included literatures ranged from 3 to 9, with an average of 6.36 scores; 2 studies of them were high quality, 6 studies were of moderate quality, 3 studies were of low quality, the overall quality was moderate.The main methodological weakness of included SRs/MAs included the lack of prior designed protocol for all studies, Incomplete literature search for partial studies, lack of a list of excluded studies, disappropriate conclusion formulation and the lack of stating the conflict of interest.The PRISMA reporting quality assessment showed that: the PRISMA checklist score ranged from 14.5 to 24.5, the average score was 20.36; 2 studies of themwere high quality,3 studies were of moderate quality, 6 studies were of low quality, the overall reporting quality was moderate; 9 entries of 27 items reported missing information(the reporting integrity was less than 50%), none of them was entirely consistent with 27 items of the PRISMA checklist. The quality of evidence based on GRADE system showed that: the H. pylori eradication rate was graded as "moderate" quality; certain probiotics(bacillus claussi, clostridium butyricum) as adjuvant therapy for H. pylori eradication rate,the level of evidence as "very low" quality; The incidence of total adverse events(GRADE classification as "low" quality); the incidence rate of diarrhea(grade classification as "moderate" quality); other adverse outcomes(grade classification as "very low" or "low" quality). The main factors contributed to downgrading evidence quality were mainly due to the limitations of study design, inconsistency, imprecision, publication bias.Conclusion:(1) Currently, the overall methodological and reporting quality of the SRs/MAs about probiotics as adjuvant therapy for H. pylori infection were moderate, research still exist different degree of methodology and reporting of quality defects, and that may decrease the reliability and value of results from SRs/MAs in the field;(2) Certain probiotics as adjuvant therapy for H. pylori infection can improve the eradication rate, reduce the incidence rate of total adverse events and diarrhea. Besides,they may has certain positive role on upper abdominal pain, nausea / vomiting, abdominal distension, but due to the GRADE evidence level was poor, clinicians should carefully so that the clinical evidence. Physicians should make an evidence-based decision with caution in clinical practice.(3) In order to improve the methodological and reporting quality, it is very necessary to develop a rigorous implementation protocol and comply with the relevant reporting standards strictly, so as to provide a more higher quality evidence for clinical decision.