Association between infection and health Outcomes: an umbrella review of systematic reviews and meta-analyses.

Objective: Systematic reviews and meta-analyses have revealed the associations between infection and various health outcomes. We aimed to evaluate the strength and breadth of evidence on the associations.

Design: Umbrella review of systematic reviews and meta-analyses.

Setting: No settings.

Participants: No patients involved.

Data Sources: Embase, PubMed, Web of Science, Cochrane Library Databases, CNKI, VIP database and Wangfang database from inception to February 1, 2019.

Outcomes Measures: Diverse diseases (such as cancer and ischaemic heart disease).

Results: Sixty articles reporting 88 unique outcomes met the eligible criteria. 74 unique outcomes had nominal significance (p<0.05). Of the outcomes with significance, 61 had harmful associations and 13 had beneficial associations. Furthermore, 73% (64) of the outcomes exhibited significant heterogeneity . Of the these meta-analyses, 32 had moderate to high heterogeneity (I=50%-75%) and 24 had high heterogeneity (I>75%). Moreover, 20% exhibited publication bias (p<0.1). In addition, 97% of the methodological qualities were rated 'critically low'. 36% of the evidence qualities of outcomes were rated 'low', 56% of the evidence qualities were rated 'very low' and 8% of the evidence qualities were rated 'moderate'. infection may be associated with an increased risk of five diseases and a decreased risk of irritable bowel syndrome.

Conclusion: Although 60 meta-analyses explored 88 unique outcomes, moderate quality evidence only existed for six outcomes with statistical significance. infection may be associated with a decreased risk of irritable bowel syndrome and an increased risk of hypertriglyceridemia, chronic cholecystitis and cholelithiasis, gestational diabetes mellitus, gastric cancer and systemic sclerosis.

Trial Registration: CRD42019124680.