Searching strategies
This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) checklist guidelines[18]. Potentially relevant articles were comprehensively searched using PubMed/MEDLINE, EMBASE, CINAHL, Google Scholar, HINARI portal (which includes the SCOPUS, African Index Medicus, and African Journals Online databases), and Cochrane Library. In addition, related articles were found from review of the grey literature available on local shelves, institutional repositories and from reviewing the cross-reference list of already identified articles. Electronic database searches were conducted from 5 May to 20 June 2019. The key terms used for the PubMed database searches were: “Prevalence”, “magnitude”, “surgical site”, “infection”, “cesarean section”, “associated factors” and “Ethiopia”. Endnote citation manager software version X7 for Windows was utilized to collect and organize search outcomes and for removal of duplicate articles.
Population: studies conducted on reproductive age women were included.
Exposure (E): studies done on post cesarean section were considered.
Outcome (O): studies conducted and reporting SSI after cesarean section were included.
Inclusion criteria
Articles were included based on the following criteria:
- published in English
- conducted in Ethiopia
- observational studies (cross sectional, case control and cohort)
- Had clear out come about surgical site infection after cesarean section
Exclusion criteria: after examining the titles and abstracts of articles using eligibility, irrelevant articles were excluded. Then those articles considered as relevant were reviewed and those which didn’t have the outcome of interest were also excluded from this systematic review and meta-analysis.
Quality of assessment
The database search results were exported and duplicate articles were removed using EndNote software (version X7; Thomson Reuters, New York, NY). We used the Newcastle‒Ottawa quality assessment scale adapted for cross-sectional studies [19, 20]. The scale is used to score the articles under three categories:
- Selection (score 0‒5);
- Comparability (score 0‒2 ); and
- Outcome (score 0‒3); total score range 0‒
The first section scored focuses on the methodological quality of each study (i.e., sample size, response rate, and sampling technique). The second section of the tool considers the comparability of different outcome groups in the study based on the study design and analysis. The last section of the tool is deal about the outcomes and statistical analysis of the original study. Two authors (TG and AN) gave score for each primary studies. The third author was considered in case of disagreement. Then studies with a score of ≥6 out of 10 were considered as high quality after reviewing different relevant literatures. Identified articles with methodological problems and incomplete reporting of results in the full text were excluded from the final meta-analysis.
We assessed and evaluated the methodological quality and risk of bias in the studies that were selected using the 10-item rating scale developed Hoy et al. for prevalence studies (Appendex-1)[21]. Sampling, data collection, reliability and validity of study tools, case definition, and prevalence periods were included in the tool. The rating scale categorized as having low risk of bias (“yes” answers to domain questions) or high risk of bias ("no" answers to domain questions) for each articles. Each study was assigned a score of 1 (Yes) or 0 (No) for each domain, and these scores were summed to provide an overall study quality score. Scores of 8-10 were considered as having a “low risk of bias”, 6–7 a “moderate risk”, and 0–5 a “high risk”. For the final risk of bias classification, disagreements between the reviewers were resolved via consensus.
Data extraction procedure
Data were independently extracted by two authors using standardized data extraction format that developed according to 2014 Joanna Briggs Institute Reviewers’ Manual [22] .The tool includes Authors, Region, study setting, study year, study design, sampling technique, sample size and prevalence of SSI after cesarean section as well as factors associated with SSI after cesarean section. Articles that fulfilled the predefined criteria were used as a source of data for the final analysis.
Outcome measurements
The primary outcome of this systematic review and meta-analysis was the pooled prevalence of SSI after cesarean section. SSI is infection related to cesarean section that occur at or near surgical incision within 30 days of operation or after one year if an implant is placed[2]. For analysis of the second outcome (risk factors of SSI after cesarean section), we extracted data on factors that had been found to be related to SSI after cesarean section in the literature, such as the presence of PROM (> 12hrs), Chorioamnionitis, duration of labor (> 24hrs), anemia and type of incision of the skin (vertical vs horizontal).
Data analysis
All the needed information on the articles were extracted using Microsoft Excel spreadsheet form and exported to STATA (version 14; Stata Corp, College Station, TX) for further analysis. The existence of statistical heterogeneity was assessed using Cochran’s Q statistic and quantifies using inverse variance (I2) and its corresponding p –value with fixed effect model of analysis. A value of 25%, 50%, and 75% were used to declare the heterogeneity test as low, medium and high heterogeneity[23]. Comparison of original articles using tabulation was computed to assess some clinical or methodological heterogeneity among the studies (Table-1). Visual examination of funnel plot asymmetry, Begg-Mazumdar Rank correlation tests and Egger’s regression tests were utilized to check for publication bias[24]. The estimated pooled prevalence of SSI after cesarean section was computed using forest plots with the 95% CI. Log odds ratio was used to identify factors associated with SSI after cesarean section.