The main objective of this protocol is to determine the impact of socioeconomic status on the outcomes of prostate cancer globally.
To compare the mortality due to prostate cancer among different socioeconomic classes.
To determine the impact of socioeconomic status on the choice of treatment, rate of recurrence, time to return to work, HRQOL and rate of secondary treatment
Does socioeconomic status affect prostate cancer outcomes?
Does socioeconomic status affect the choice of prostate cancer treatment?
Are prostate cancer outcomes moderated by mean income, educational status, race, and medical insurance status?
This is a protocol for systematic review and meta-analysis of observational studies that reported the impact of socioeconomic status on the outcome of prostate cancer worldwide. Other types of study designs are excluded including interventional studies, comments and editorials. There is no time restriction on eligible primary studies.
Inclusion criteria are:
Observational studies (cohort, cross-sectional, case-control, historical cohort)
Studies of all years that are published and or retrievable in the English language
Studies that are available in electronic databases.
Studies that report socioeconomic status impact on any of the prostate cancer outcomes (the primary outcome is socioeconomic status of prostate cancer patients) and/ or secondary outcomes such as mortality, survival, HRQOL, recurrence, choice of treatment regrets and time of return to work.
Exclusion criteria are:
Narrative reviews, interventional and experimental studies
Letters to the editor
Studies that are not reported or retrievable in the English language
Studies without data on socioeconomic status of prostate cancer patients.
Grey literature will not be included.
The PICOS is as follows
Participants: men with prostate cancer worldwide
Intervention: There is no intervention
Comparator: There is no comparator
Outcome: The primary outcome is socioeconomic status (SES) of prostate cancer patients. The measurable secondary outcomes are mortality, HRQOL including depression and time of return-to-work, recurrence, need for secondary treatment, treatment choice regret, unknown risk category and hospice enrollment. Filters used for subgroups are SES, income, education, insurance and race.
The search will employ sensitive topic-based strategies designed for each database. The nine databases to be searched are CINAHL, PubMed, Web of Science, Google Scholar, African Journal Online, Scopus, ResearchGate, Embase, and Cochrane Library. The study will include only observational studies retrievable in the English language.
There is no time frame/restriction in the inclusion of publications.
The search strategy included MeSH terms, text words and entry words. The search strategies that were used are shown in Table 1.
Data Extraction and Management
Three tools will be used for data extraction and management: i) Zotero software, ii) Microsoft Excel and iii) Comprehensive Meta-analysis software CMA version 3
a) Screening: Studies will be screened at four levels:
Level 1: screening to select only observational studies while other study designs are excluded.
Level 2: screening titles and abstracts of observational studies using MeSH terms, keywords, and entry terms.
Level 3: screening of the selected studies by full-text reading, using the same strategy
Level 4: snowballing of the literature using included studies
b) Reviewers: Fifteen reviewers are involved in this study. Two reviewers will independently screen studies from each database and assess studies for inclusion and or exclusion. Conflicts will be resolved by a third reviewer. All reviews are blinded.
C) Selection process: The screening and deduplication will be done in Zotero software. Studies will be selected based on eligibility criteria and primary measurable outcome. Authors of studies with missing data will be contacted via email and telephone.
d) Data collection:
The following data items will be extracted from each eligible study into Microsoft Excel:
first author’s surname and year of publication of the study,
socioeconomic status: income, educational level, insurance status
prostate outcomes: mortality due to prostate cancer, HRQOL including depression and time of return-to-work, recurrence of the prostate cancer, need for secondary treatment, treatment choice regret, unknown risk category, and hospice enrollment,
Data from Microsoft Excel will be exported to CMA software for meta-analysis
Data items (Main measurable outcomes)
The measurable data items in this study are:
socioeconomic status including numerical data such as income, categorical data such as educational status, and categorical data such as health insurance status. The effect size is mean or median income status.
prostate cancer-specific mortality rate (categorical data), prostatic cancer recurrence rates (numerical data), health related quality of life (numerical data), recurrence of prostate cancer (categorical), choice of treatment regrets (categorical), and time of return to work (numerical)
Risk of bias
The risk of bias in included studies will be accessed for the individual studies using the National Institute of Health (NIH) Quality assessment tool for observational cohort and cross-sectional studies. This will be cross-checked with the Cochrane tool of risk of bias assessment for the strength of the body of evidence, i.e., using specific relevant items from this tool to assess the strength of the body of evidence.
Studies with extreme bias may be excluded after assessment in the following areas:
Method of testing and reporting at the outcome level
Heterogeneity will be assessed at the study level
Publication bias will be assessed at the study level
Sensitivity test using include/exclude function in the CMA software will be done at the study level
Studies that passed the methodological quality assessment using the NIH quality assessment tool will be extracted. The results will be presented in tabular format in addition to a narrative synthesis.
The following shall be included in the meta-analysis:
i) Report on socioeconomic status. Mean income status will be expressed in cohen’s d as the effect size.
ii) Subgroups analysis will be done using moderators such as educational status, insurance status, treatment option, race, recurrence of prostate cancer and choice of treatment regret.
Eligible studies will be quantitatively analyzed using the Comprehensive Meta-analysis CMA Software, Version 3 (BioStat USA). The random effect model will be used for computation.
In addition to subgroup analysis, a meta regression will be performed using numerical independent variables such as time to return to work, patients age and health related quality of life while income status will be the outcome variable.
A cumulative meta-analysis will be performed to check for trends on SES and prostate outcomes over years.
Assessment of Meta-bias
To test for heterogeneity Q value, I2, Τ2 will be used. I² values of less than 40% will be considered low heterogeneity, values > 40 to ≤75 % moderate while values > 75% are high. Publication bias will be assessed using a funnel plot and test of assymmetry. Sensitivity test using include /exclude function will be performed in the CMA software.