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Latitude of the study place and age of the patient are associated with incidence of mediastinitis and microbiology in open-heart surgery: a systematic review and meta-analysis

Authors Abdelnoor M, Vengen, Johansen O, Sandven I, Abdelnoor A

Received 10 September 2015

Accepted for publication 29 February 2016

Published 2 June 2016 Volume 2016:8 Pages 151—163


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Professor Henrik Toft Sørensen

M Abdelnoor,1,2 Ø A Vengen,3 O Johansen,4 I Sandven,2 AM Abdelnoor5

1Centre for Clinical Heart Research, Department of Cardiology 2Oslo Centre for Biostatistics and Epidemiology, 3Department of Cardiovascular Surgery, 4Department of Cardiology, Oslo University Hospital, Oslo, Norway; 5Department of Experimental Pathology, Immunology and Microbiology, American University of Beirut, Beirut, Lebanon

Objective: We aimed to summarize the pooled frequency of mediastinitis following open-heart surgery caused by Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), and Gram-negative bacteria.
Design: This study was a systematic review and a meta-analysis of prospective and retrospective cohort studies.
Materials and methods: We searched the literature, and a total of 97 cohort studies were identified. Random-effect model was used to synthesize the results. Heterogeneity between studies was examined by subgroup and meta-regression analyses, considering study and patient-level variables. Small-study effect was evaluated.
Results: Substantial heterogeneity was present. The estimated incidence of mediastinitis evaluated from 97 studies was 1.58% (95% confidence intervals [CI] 1.42, 1.75) and that of Gram-positive bacteria, Gram-negative bacteria, and MRSA bacteria evaluated from 63 studies was 0.90% (95% CI 0.81, 1.21), 0.24% (95% CI 0.18, 0.32), and 0.08% (95% CI 0.05, 0.12), respectively. A meta-regression pinpointed negative association between the frequency of mediastinitis and latitude of study place and positive association between the frequency of mediastinitis and the age of the patient at operation. Multivariate meta-regression showed that prospective cohort design and age of the patients and latitude of study place together or in combination accounted for 17% of heterogeneity for end point frequency of mediastinitis, 16.3% for Gram-positive bacteria, 14.7% for Gram-negative bacteria, and 23.3% for MRSA bacteria.
Conclusion: Evidence from this study suggests the importance of latitude of study place and advanced age as risk factors of mediastinitis. Latitude is a marker of thermally regulated bacterial virulence and other local surgical practice. There is concern of increasing risk of mediastinitis and of MRSA in elderly patients undergoing sternotomy.

Keywords: mediastinitis, sternotomy, meta-analysis

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