A meta-analysis of type 1 diabetes mellitus, all-cause and cause-specific mortalit

Bowen-Jones, David

Cooper, Helen

Eloho, Akata

Mabhala, Mzwandile A.

ChesterRep

 PROSPERO International prospective register of systematic reviews A meta-analysis of type 1 diabetes mellitus, all-cause and cause-specific mortalityEloho Akata, Andi Mabhala, Helen Cooper, David-Bowen Jones  CitationEloho Akata, Andi Mabhala, Helen Cooper, David-Bowen Jones. A meta-analysis of type 1 diabetes mellitus, all-cause and cause-specific mortality. PROSPERO 2016:CRD42016037564 Available from  http://www.crd.york.ac.uk/PROSPERO_REBRANDING/display_record.asp?ID=CRD42016037564  Review question(s)• What risk factors are associated with mortality in T1DM?• How do these risk factors affect mortality rates in individuals diagnosed with T1DM as compared to the generalpopulation?• Are there any gender difference in individuals diagnosed with T1DM?SearchesRelevant studies will be searched for regardless of publication status i.e. published and unpublished studies. An initial search will cover electronic databases such as PubMed, MEDLINE, Campbell Library of SystematicReviews, Cochrane Database of Systematic Reviews (CDSR), EMBASE and PAIS International, the CochraneCentral Register of Controlled Trials (CENTRAL), LILACS, World Health Organisation Library and InformationNetwork for Knowledge database (WHOLIS), The Centre for Evidenced-Based Medicine, PsycINFO, GoogleScholar, National Library for Health, Ongoing Reviews database, British Nursing Index and Scopus (Higgins &Green, 2011). The search for unpublished works will be done through assessing grey literature such as UK National ResearchRegister (NRR), ReFeR, Kings Fund and Conference Papers Index. FADE, ProQuest Dissertation and mTheses, andother Indexed Citations up to 2015, National Technical Information Service (NTIS) and Health ManagementInformation Service. A manual search will be undertaken of reference lists of all studies identified by the above methods.Non-English language databases like the LILACS (Latin American and Caribbean Health Sciences) will be assessedprovided they are translated into English language to reduce the risk of language bias (CRD, 2008). Bibliographicdatabases such as BIOSIS will also be assessed for previews of materials from conferences. The search strategy will involve using keywords and phrases, including Medical Subject Headings (MeSH) related tothe inclusion criteria for the study. The search period instituted will be between January, 1960 and March, 2016.Types of study to be included• Existing systematic reviews;• Epidemiological studies; • Randomised controlled trials of interventions in the management of T1DM.Condition or domain being studiedMortality in type 1 diabetes.                               Page: 1 / 5Participants/ populationParticipants diagnosed with T1DM before the age of 40 years as it becomes increasingly difficult to differentiatebetween type 1 and type 2 diabetes after this age.Intervention(s), exposure(s)The nature of the outcome to be reviewed in this study is mortality after the diagnosis of type 1 diabetes. Exclusions are as follows;(1) Any study that has a CASP score (Quality appraisal) less than 8;(2) Studies in which the participants acquire type 1 diabetes from a secondary cause;(3) Studies that only have an abstract and the full paper is not accessible;(4) Studies in which there is no differentiation between type 1 or type 2 diabetes in participants;(5) Studies that do not have any comparison population (either cohort or general population); (6) Studies without adequate data for analysis.Comparator(s)/ controlThe studies included will have a comparison population which will be either a comparison cohort or the generalpopulation.Outcome(s)Primary outcomesOverall mortality rate/all-cause mortality. The outcome measures used will be the standardized mortality ratio (SMR) as a form of relative risk (RR).Secondary outcomesSecondary outcomes include mortality in relation to:1. Gender;2. Year of study publication;3. Follow-up duration;4. Cause (overall and according to gender);a) Cardiovascular disease (inclusive of coronary artery disease, myocardial infarction, heart failure/disease, ischemicheart disease);b) Cerebrovascular disease (stroke);c) Renal disease;d) Cancer;e) Accidents and suicide.Data extraction, (selection and coding)This process entails retrieving the information needed from the studies included in this review. The process can becarried out manually or electronically (CRD, 2008). Forms will be developed, modified, and adapted to the CRDtemplate (CRD, 2008). The following data will be extracted from individually selected studies: author, year of                               Page: 2 / 5publication, study design, setting/location, year of study, comparison population, study size, number of deaths,patients’ characteristics, follow-up years, outcome measure(s) of mortality, and degree of mortality in standardizedmortality ratios (SMRs). The process of data extraction will be carried out by one reviewer (AE) any discrepancieswill be addressed by two other reviewers (HC) and (DBJ).Risk of bias (quality) assessmentHaving ensured that studies meet the inclusion/exclusion criteria, the next stage will be to quality appraise the studiesusing the Critical Appraisal Skill Programme [CASP] tool (Higgins & Green, 2011). The CASP tool uses a check listthat assesses systematic reviews, randomized control trials, case controls and cohort studies. The process will bedocumented and each study will be scored. This process will be carried out by one reviewer (AE) and triangulated by(HC) and (DBJ). CASP scores will be assigned to the study and any study scoring less than 9 out of an overall scoreof 12 will be excluded from the quantitative analysis. The quality appraisal will assess the following three broad categories:• Are the results valid? • What are the results?• Will the results help locally?Strategy for data synthesisWe intend to conduct a narrative synthesis on the studies included in tabular format. This table will include asynthesis of the studies included, a consideration of factors such as study characteristics/type, study participantscharacteristics, settings and outcomes measured. We will also calculate the risk ratios using standardized mortalityratios (SMR) as a form of relative risk. The estimations of risk ratios (RR) will involve calculating the log (SMR) andstandard errors (SE), back transformed to estimate the risk ratios (RR) at 95% confidence limits using the statisticalsoftware Review Manager version 5.3. We also intend to conduct a meta-analysis using the outcomes identified,estimating the average pooled effect estimate of the studies included at 95% confidence intervals. The analysis forthis study will be either a random or a fixed-effect meta-analysis. It is anticipated that for a study of this nature, therewill exist a certain amount of heterogeneity of the studies included because of variations in study populations,settings, and outcome measures. We intend to measure heterogeneity between study characteristics by assessing the I-squared estimate. Any values greater than 60% will considered as having significant levels of heterogeneity and anexclusion sensitivity analysis will be carried out to find out which studies contribute to the degree of heterogeneityobserved.Analysis of subgroups or subsetsWe intend to conduct subgroup meta-analyses based on year of study publication and follow-up duration. The follow-up duration will be categorized into follow-up durations of less than 10 years, between 10 and 20 yearsand greater than 20 years. Assessing the subgroup analysis on follow-up duration will be done as a proxy to estimatesurvival with disease progression. Subgroup analysis based on study publication will consider publication years before the year 2000, publicationsbetween 2000 and 2010, and publications after the year 2010. This analysis will be done as a proxy to estimate thetemporal trend in the management of type 1 diabetes.Dissemination plansWe intend to communicate the essential messages of this review in conferences, and seminar meetings.Contact details for further informationEloho Akata9 Bouverie Street, Chester, CH1 4HF, Cheshireeloho3@yahoo.co.uk                               Page: 3 / 5Organisational affiliation of the reviewDepartment of Public Health and Wellbeing, Faculty of Health and Social Care, University of Chesterwww.chester.ac.uk/health/phwReview teamDr Eloho Akata,Dr Andi Mabhala, Department of Public Health and Wellbeing, Faculty of Health and Social Care, University ofChesterProfessor Helen Cooper, Professor, Public Health and Wellbeing,Department of Public Health and Wellbeing,Faculty of Health and Social Care, University of ChesterProfessor David-Bowen Jones, Wirral University Teaching HospitalAnticipated or actual start date02 November 2015Anticipated completion date29 May 2016Funding sources/sponsorsNoneConflicts of interestNone knownLanguageEnglishCountryEnglandSubject index terms statusSubject indexing assigned by CRDSubject index termsDiabetes Mellitus, Type 1; Epidemiology; Humans; Mortality; Risk FactorsAny other informationThis review is being undertaken as part of a PhD project in type 1 diabetes. AE, HC and DBJ are investigators for theproposed systematic review. AE and HC proposed the study, HC, DBJ, and MA are reviewers and supervisors of thestudy.Stage of reviewOngoingDate of registration in PROSPERO11 April 2016Date of publication of this revision11 April 2016Stage of review at time of this submission Started CompletedPreliminary searches Yes   Yes Piloting of the study selection process   Yes   Yes                                Page: 4 / 5Formal screening of search results against eligibility criteria   Yes   Yes Data extraction   Yes   No Risk of bias (quality) assessment   No   No Data analysis   No   No  PROSPEROInternational prospective register of systematic reviewsThe information in this record has been provided by the named contact for this review. CRD has accepted this information in goodfaith and registered the review in PROSPERO. CRD bears no responsibility or liability for the content of this registration record,any associated files or external websites. 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A meta-analysis of type 1 diabetes mellitus, all-cause and cause-specific mortality

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A meta-analysis of type 1 diabetes mellitus, all-cause and cause-specific mortality

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