We will consider quantitative results of the association between potential determinants and the utilization of child health care services. Published results must include an association measure, frequency ratio/difference, or statistical test comparing utilization of child health care services across two or more groups.
If these results are not explicit, we have to be able to estimate them with the information provided in the paper. We will consider relative comparisons –for example, relative concentration index (RCI) or relative index of inequity (RII) - to a reference group, along with absolute differences in child health care services utilization, such as absolute concentration index (ACI) or slope index of inequity (SII). Such reported disparities will be useful in making comparisons over time or across geographical areas, populations or indicators, in light of the Centers for Disease Control and Prevention (CDC)’s guidelines [16, 17]. Studies strictly reporting qualitative results on access to child health care utilization are excluded. Within the same publication, results for the most recent year will be appraised if information exists for consecutive years. In the case of secondary analyses from national representative surveys such as the Demographic and Health Surveys (DHS) for consecutive years in the same country, we will only consider the most recent .
Study selection procedure
Screening
A team of researchers, HF will identify articles by first analyzing titles and abstracts for relevance and compliance with the selection criteria, based on research setting, study design, reported outcomes and determinants of interest. Relevant articles will be classified as: 1) included; 2) excluded; or 3) uncertain. After exclusion of records not relevant to the systematic review, full texts of selected abstracts (records categorized as included or uncertain) will be extracted systematically for further eligibility analysis.
Eligibility
Full-text screening will be conducted independently by the reviewers (HF) using a standardized form with explicit inclusion and exclusion criteria. Discrepancies will be resolved by discussion between the two reviewers, and persisting disagreement will be resolved by discussions with two experienced researchers.
Data collection process
Reviewers will use an explicit data collection form to abstract data items, including but not limited to: study characteristics (country, setting, year of publication, study design, sample size); participants’ characteristics (mean age ± SD, health literacy, women’s decision making power); outcomes (child health care service utilization); and results of the association between child health care services and potential determinants.
In cases where numerous publications report data originating from the same study, the latest outcomes of interest will be assessed. Missing data on key characteristics will be dealt with by contacting the study authors and through complementary research. Reviewers will systematically use a standardized data abstraction form. To increase the reliability of data abstraction by the reviewers, a pilot test of the standardized form will be performed on a random sample, and the tool will be refined as necessary.
Methodological quality assessment
We will assess the scientific quality of selected studies to ensure internal validity of reported results and avoid analyzing false associations - confounded or biased – or type I statistical errors. We will use standardized quality assessment tools for specific types of designs to determine the methodological quality and the risk of bias of the included studies. To assess the quality of cohort, case control and cross-sectional studies, we will use the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies, adapted to extend the criteria for selection bias assessment [18].Special attention will be provided to precise study objectives, explicit identification of the population studied, clear definitions of outcomes, independent factors, potential confounders and effect modifiers. According to the methodological characteristics appraised, we will classify the studies’ scientific quality as either 1) Strong, 2) Moderate or 3) Weak.
Search results
Evidence tables will be generated to descriptively summarize the included studies and results: 1) authors, 2) study design, 3) objectives, 4) setting, 5) population, 6) outcomes assessed, 7) determinants/predictors, 8) results and 9) scientific quality. Evidence tables will be stratified
by countries’ income level (World Bank classification) to provide for different contextual characteristics of low versus middle-income countries.
Data synthesis
Where feasible, data will be combined to obtain a pooled measure of association evaluating child health care services inequities, through meta-analyses conducted by’ using The Cochrane Group’s Review Manager Software (RevMan 5.1) [19]. Data will be analyzed along subsets defined by the countries' income level and grouped by determinants of child health care services utilization (socioeconomic, geographic, demographic). Due consideration will be given to heterogeneity (I2 statistic) and corresponding analysis (fixed versus random-effects models; meta-regression, if necessary). Depending on the number of studies, we will further stratify observational studies according to design (cohort, case–control, cross-sectional) and/or association measure - odds ratio, risk ratio, incidence rate ratio, hazard ratio, and prevalence ratio - exploring potential heterogeneity.
will be paid to assessing results in light of study settings to ensure proper contextualization of evidence and relevance for policy planning purposes in LMICs. Results will be reported according to the PRISMA Statement, with a focus on health equity (PRISMA-Equity 2012 Extension) [20].