Objective
The main objective of this study is to determine the pooled prevalence of
asymptomatic bacteriuria in Nigerian pregnant women as well as the associated risk factors and pregnancy outcomes.
The specific objectives include:
- To determine the pooled prevalence of asymptomatic bacteriuria amongst pregnant Nigerian women.
- To evaluate the associated risk factors such as socioeconomic status,history of recurrent urinary tract infection (UTI), diabetes mellitus, and anatomical abnormalities of the urinary tract, sickle cell and retroviral diseases for asymptomatic bacteriuria in the pregnant Nigerian women.
- To assess pregnancy outcomes such as preterm birth, anemia, and pyelonephritis in asymptomatic bacteriuria
Review Questions
- What is the pooled prevalence of asymptomatic bacteriuria amongst pregnant Nigerian women?
- What are the frequencies of the risk factors associated with asymptomatic bacteriuria in pregnancy?
- What are the frequencies of adverse feto-maternal outcomes associated with asymptomatic bacteriuria?
Study Characteristics
a. Study Design:
This is a protocol for systematic review and meta-analysis of observational studies that reported the prevalence of asymptomatic bacteriuria amongst pregnant women in Nigeria. There is no time restriction. Other types of study designs are excluded including interventional studies, comments, and editorials.
b. Inclusion criteria
- Observational studies e.g., cross-sectional, case-control, cohort, retrospective, and historical cohort studies;
- the study must report the prevalence of asymptomatic bacteriuria in pregnancy as a primary outcome.
- the study must be retrievable in the English language.
- the study must be available in electronic databases.
c. Exclusion criteria
- Letters to editors, reviews, commentaries, and editorials.
- Duplicate of same studies.
- Studies with secondary but no primary outcome.
- Studies on the prevalence of asymptomatic bacteriuria but not in pregnancy.
- Interventional studies including randomized clinical trials and quasi-clinical trials.
- Non-Nigerian studies or studies on Nigerians in the diaspora.
- Grey literature will not be included.
PICOs
Participants are all pregnant Nigerian women with asymptomatic bacteriuria.
Intervention: there is no intervention.
Comparator: there is no comparator.
Outcomes: the primary outcome is the proportion of asymptomatic bacteriuria in pregnant women in Nigeria. Secondary outcomes are: - a) frequencies of risk factors including recurrent UTI, SCD, HIV infection, parity, urinary tract abnormalities, urethral catheterization, and pyelonephritis; and b) pregnancy
outcomes will include the proportion of preterm delivery, intrauterine growth restriction, neonatal sepsis; and puerperal sepsis.
Effect size for the primary outcome is the prevalence
Effect size for secondary outcomes is prevalence except for categorical variables that serve as moderators.
Information sources
The search will employ sensitive topic-based strategies designed for each
database. The following databases will be searched: CINAHL, Embase, PubMed, Web of Science, Google scholar, African journals online (AJOL), Scopus,
ResearchGate, and Cochrane Library. Only observational studies that are
conducted in Nigeria and retrievable in the English Language will be included.
Search strategy
The search strategy will include MeSH terms, text words, and entry terms. The
Search strategies used in databases are as shown in Table 1.
Data Extraction and Management
Three main tools will be used to manage data: DistillerSR, CMA software version 3 and Microsoft Excel.
a. Screening: Identified studies will be independently and blindly screened in pairs using the DistillerSR software at the following levels:
- Level 1: study design: only observational studies will be included.
- Level 2: screening of titles and abstracts of identified studies using search strategy.
- Level 3: full texts will be screened using search strategy.
- Level 4: Snowballing of articles to identify more relevant studies.
- Level 5: Studies will be screened for primary and secondary outcomes.
- Level 6: Studies will be screened for risk of bias using NIH Quality assessment for observational studies.
Conflicts during screening will be resolved by a third reviewer, who serves as a tiebreaker.
b. Selection process: Studies will be selected based on study design, inclusion/exclusion criteria, and screening outcomes. Full-text articles will be obtained for all included studies. Primary outcomes must be reported in all eligible studies. Authors of eligible articles with missing data will be contacted by email and telephone. Depulication of eligible studies will be performed using the DistillerRS.
c. Data collection process: Extractable data item will be collected into predefined forms created in the DistillerSR. Extractable data items from eligible studies will include:
- Surname of first author and year of publication
- Proportion of asymptomatic bacteriuria in pregnant Nigerian women (prevalence)
- Mean patient’s age
- Risk factors: recurrent UTI, SCD , HIV infection, parity, urinary tract abnormalities, urethral catheterization, and pyelonephritis
- Pregnancy outcomes: the proportion of preterm delivery, intrauterine growth restriction, neonatal sepsis; and puerperal sepsis.
- Method of detecting bacteriuria: dipstick, culture, and PCR
The effect size for primary outcome is prevalence. Effect size for most of the secondary outcomes is prevalence.
Risk of bias
The risk of bias in eligible studies will be accessed for the individual studies using the National Institute of Health (NIH) Quality assessment tool for observational studies. This will be cross-checked with the Cochrane tool of risk of bias assessment for the strength of the body of evidence.
The following areas shall be assessed and any study with extreme bias will be
excluded following a consensus decision.
- Method of testing and reporting at the outcome level
- Reporting of study: whether proportion/ prevalence with confidence interval or number of cases / sample size are reported at the outcome level. Primary indexes from studies with similar design and report outcome will be converted to prevalence which is the primary effect size.
- Heterogeneity will be assessed at the study level.
- Publication bias will be assessed at the study level.
- Sensitivity analysis will be done at the study level.
Assessment of Meta-bias
To test for heterogeneity: Cochrane’s Q value and its p-value, I², Ʈ² will be used. The effect size is the prevalence at a 95% Confidence Interval (CI, 95%). As a rule of thumb, I² values of less than 40% will be considered low heterogeneity while values > 40 but < 75 % will be considered moderate and values > 75% are high.
Data synthesis:
Both narrative synthesis and quantitative analysis will be performed.
All studies that report primary outcomes with or without secondary outcomes will be included for systematic review, with all measurable outcomes and sample size reported in a tabular format. Studies with primary indices that can be converted to prevalence will be converted in the CMA Software version 3.
Quantitative Analysis
Quantitative data will include pooled prevalence, standard error, and 95% CI. Both random and fixed effect models will be assessed, and the appropriate model will be taken based on the forest plots. Quantitative analysis will be done using the Comprehensive Meta-analysis CMA software version 3.
Further Analysis
Subgroups analysis will be done using categorical risk factors and pregnancy outcomes as moderators. Meta-regression will be done with mean maternal age and parity. A cumulative meta-analysis will be performed to check for the trend in the prevalence of asymptomatic bacteriuria over the years.
Presentation and Reporting of Results
The study selection process will be summarized in a Prisma flow chart according to the PRISMA 2015 Statement and PRISMA-P Checklist [24,25]. A table of the search strategy in various databases will be presented. A list of included studies will be summarized in a table. Quantitative data: prevalence, standard error, 95 % CI, P values, relative weights assigned to studies, and heterogeneity tests will be reported in the forest plots. A table of quality scores and risk of bias of each eligible study will be presented. Forest and regression plots to show subgroup analysis and meta-regression respectively will be presented as well.