Searching strategies and Study design
This review was considered to evaluate the combined magnitude and predictors of pneumonia among under-five children in Ethiopia. In this review, we searched databases without limit to the date of publication and study design. To confirm the scientific accuracy, the Preferred Reporting Items of Systematic Reviews and Meta-Analysis Protocol (PRISMA- P) guideline was used [14]. The international databases include MEDLINE/PubMed, EMBASE, Web of Sciences, Scopus, and Grey literature databases, Google Scholar, Science Direct and Cochrane library were scientifically explored. Also, we assessed reference lists of the articles found through the database search to retrieve additional articles and included the articles relevant to our topic of review. Unpublished studies were retrieved from the official websites of international and local organizations and universities. The search was performed by keywords, medical subject headings (MeSH) terms. We used the search terms independently and/or in combination using “OR”, “AND” or “NOT”. Keywords/search terms were “magnitude” OR “Epidemiology” AND “Children” AND/OR “Under Five Children” AND/OR “Childhood” AND/OR “factors” AND/OR “associated factors” AND/OR “risk factors” AND/OR “determinants” AND/OR “predictors” AND” Ethiopia”. All articles conducted from September 30, 2019, up to November 30, 2019, and all accessible studies up to November 30, 2019, were incorporated in our meta-analysis and systematic review.
Study Identification, Selection and Eligibility Criteria
This meta-analysis and systematic review included the primary studies that assessed the magnitude of pneumonia and predictors among under-five children in Ethiopia.
Inclusion criteria
The magnitude and associated risk factors of pneumonia among under-five children in Ethiopia
Study area: Only articles conducted in Ethiopia.
Study design: All observational studies (cross-sectional, case controls, and cohort) that contain original data reporting the prevalence and associated risk factors of pneumonia among under-five children in Ethiopia were considered.
Language: It included literature published in English.
Population: Studies carried out in Ethiopia among children under five were considered.
Publication condition: A consideration was extended to both published articles and unpublished work in English.
Exclusion criteria: Research that was unpublished, irretrievable from the internet or failed to receive email replies from the corresponding authors was excluded. Furthermore, research which did not report our results of interest was excluded after a complete review of the texts
Outcome of interest
The main result of this study was to estimate the pooled magnitude and identify pneumonia predictors among children under five in Ethiopia.
Data extraction and synthesis
Data were retrieved by two independent reviewers (YM and FA) by using a standardized data extraction spreadsheet format. The data abstraction format includes the author, the study year, region of study setting (region and rural or urban), study design, sample size, magnitude, and predictor variables. Any disagreements during the extraction process were solved by consensus between the reviewers. If we got incomplete data, we excluded the study after two attempts were made to contact the corresponding author by email. Also, the two authors (YM and FA) performed the quality assessment of studies independently. Any discrepancy was resolved by discussion and agreement.
Quality Assessment (appraisal) of the individual studies
Duplicate articles were removed manually using Endnote (version X8) after combining the Database search results. To assess the quality of each study, Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) adapted for both cross-sectional and case-control study design was used [15]. The original study was assessed by two reviewers independently and any disagreement between the reviewers was solved by taking the mean score of the two reviewers. Finally, the original studies which score five and above were included in the final review.
Statistical methods and analysis
For farther analysis, we imported the data to STATA version 14.0 statistical software after extracting the data using Microsoft Excel format.
Using the binomial distribution formula, Standard error was calculated for each study. The overall pooled magnitude of pneumonia among under-five children in Ethiopia was calculated using the standard error (SE) from each study. The pooled magnitude of pneumonia with 95% CI was presented using forest plots and Odds ratio (OR) with 95% CI was also presented in forest plot to show the predictors with pneumonia. We identify the heterogeneity between the studies using Cochrane's Q statistics (Chi-square), inverse variance (I2) and p-values [16]. Heterogeneity or variation across studies was assessed using the inverse variance (I2) with Cochran Q statistic at 25%, 50% and 75% was used to declare as low, moderate and high heterogeneity respectively [17]. The statistical output showed that there was significant heterogeneity among the studies (I2 = 97.9%, P ≤ 0.001) so that we used a random-effects meta-analysis model to estimate the pooled magnitude and predictors of pneumonia among under-five children in Ethiopia. Also, we used a forest plot to detect the presence of heterogeneity. Furthermore, subgroup analysis was conducted by region of the study, study period and sample size, and meta-regression were used to identify the possible source of heterogeneity. The evidence of publication bias was checked using funnel plot symmetry. Besides, the statistical significance of publication bias was assessed using both Egger's and Beggar's test, subsequently, a trim-and-fill analysis was performed, with the p-value, less than 5% was used to declare the presence of publication bias [18, 19].