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Methodological quality of behavioural weight loss studies: a systematic review.

ABSTRACT: This systematic review assessed the methodological quality of behavioural weight loss intervention studies conducted among adults and associations between quality and statistically significant weight loss outcome, strength of intervention effectiveness and sample size. Searches for trials published between January, 2009 and December, 2014 were conducted using PUBMED, MEDLINE and PSYCINFO and identified ninety studies. Methodological quality indicators included study design, anthropometric measurement approach, sample size calculations, intent-to-treat (ITT) analysis, loss to follow-up rate, missing data strategy, sampling strategy, report of treatment receipt and report of intervention fidelity (mean?=?6.3). Indicators most commonly utilized included randomized design (100%), objectively measured anthropometrics (96.7%), ITT analysis (86.7%) and reporting treatment adherence (76.7%). Most studies (62.2%) had a follow-up rate?>?75% and reported a loss to follow-up analytic strategy or minimal missing data (69.9%). Describing intervention fidelity (34.4%) and sampling from a known population (41.1%) were least common. Methodological quality was not associated with reporting a statistically significant result, effect size or sample size. This review found the published literature of behavioural weight loss trials to be of high quality for specific indicators, including study design and measurement. Identified for improvement include utilization of more rigorous statistical approaches to loss to follow up and better fidelity reporting.

SUBMITTER: Lemon SC

PROVIDER: S-EPMC5996374 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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Methodological quality of behavioural weight loss studies: a systematic review.

Lemon S C SC Wang M L ML Haughton C F CF Estabrook D P DP Frisard C F CF Pagoto S L SL

Obesity reviews : an official journal of the International Association for the Study of Obesity 20160412 7

This systematic review assessed the methodological quality of behavioural weight loss intervention studies conducted among adults and associations between quality and statistically significant weight loss outcome, strength of intervention effectiveness and sample size. Searches for trials published between January, 2009 and December, 2014 were conducted using PUBMED, MEDLINE and PSYCINFO and identified ninety studies. Methodological quality indicators included study design, anthropometric measur ...[more]

PMID: 27071775

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Project description:ObjectiveTo determine if the characteristics of behavioural weight loss programmes influence the rate of change in weight after the end of the programme.DesignSystematic review and meta-analysis.Data sourcesTrial registries, 11 electronic databases, and forward citation searching (from database inception; latest search December 2019). Randomised trials of behavioural weight loss programmes in adults with overweight or obesity, reporting outcomes at ≥12 months, including at the end of the programme and after the end of the programme.Review methodsStudies were screened by two independent reviewers with discrepancies resolved by discussion. 5% of the studies identified in the searches met the inclusion criteria. One reviewer extracted the data and a second reviewer checked the data. Risk of bias was assessed with Cochrane's risk of bias tool (version 1). The rate of change in weight was calculated (kg/month; converted to kg/year for interpretability) after the end of the programme in the intervention versus control groups by a mixed model with a random intercept. Associations between the rate of change in weight and prespecified variables were tested.ResultsData were analysed from 249 trials (n=59 081) with a mean length of follow-up of two years (longest 30 years). 56% of studies (n=140) had an unclear risk of bias, 21% (n=52) a low risk, and 23% (n=57) a high risk of bias. Regain in weight was faster in the intervention versus the no intervention control groups (0.12-0.32 kg/year) but the difference between groups was maintained for at least five years. Each kilogram of weight lost at the end of the programme was associated with faster regain in weight at a rate of 0.13-0.19 kg/year. Financial incentives for weight loss were associated with faster regain in weight at a rate of 1-1.5 kg/year. Compared with programmes with no meal replacements, interventions involving partial meal replacements were associated with faster regain in weight but not after adjustment for weight loss during the programme. Access to the programme outside of the study was associated with slower regain in weight. Programmes where the intensity of the interaction reduced gradually were also associated with slower regain in weight in the multivariable analysis, although the point estimate suggested that the association was small. Other characteristics did not explain the heterogeneity in regain in weight.ConclusionFaster regain in weight after weight loss was associated with greater initial weight loss, but greater initial weight loss was still associated with reduced weight for at least five years after the end of the programme, after which data were limited. Continued availability of the programme to participants outside of the study predicted a slower regain in weight, and provision of financial incentives predicted faster regain in weight; no other clear associations were found.Study registrationPROSPERO CRD42018105744.

Project description:BACKGROUND:Behavioural weight management programmes are effective in assisting people with overweight or obesity to lose excess body weight. Yet, many still struggle to attain their weight loss goals in such programmes. Little is understood about the factors which impact success in these programmes. Synthesising this data will allow for theory to be developed on how to improve success in such programmes. The main aim of this review will be to extract and synthesise the barriers and facilitators of successful weight loss during participation of behavioural weight loss programmes in adults living with overweight and obesity. METHODS:A systematic search of MEDLINE, Embase, PsycINFO, The Cochrane Library and CINAHL will be performed from inception onwards. Studies will also be sought by contacting experts in the field, reference and website searching. Studies will be eligible if the participants are adults living with obesity (population) undertaking or recently completed behavioural weight loss programmes (intervention) with the primary focus of weight loss (outcome). The primary outcomes will be amount of weight lost and information on barriers and/or facilitators to success. The secondary outcomes will be reasons or factors related to attrition and adherence and behaviour change techniques used in programmes. Two reviewers will screen citations and full-text data. Reviewer 1 will screen all, and reviewer 2 will screen a random 50% of articles. Data extraction will be completed by reviewer 1, and 10% will be checked by the research team. Potential conflicts will be resolved through discussion. Data will be synthesised and described narratively to show the characteristics of each study, levels of success and barriers and facilitators during programme participation. A thematic approach will be taken, and themes will be coded against the levels of the socioecological model. Quantitative data will be extracted and categorised according to these themes and presented alongside the qualitative data. DISCUSSION:Our findings can be used to inform how weight loss programmes can be improved to facilitate success in those at risk of failure. Results will be published in a peer-reviewed journal. SYSTEMATIC REVIEW REGISTRATION: ( PROSPERO CRD42019148158 ).

Project description:OBJECTIVES:To assess the methodological quality of prognostic model development studies pertaining to post resection prognosis of pancreatic ductal adenocarcinoma (PDAC). DESIGN/SETTING:A narrative systematic review of international peer reviewed journals DATA SOURCE: Searches were conducted of: MEDLINE, Embase, PubMed, Cochrane database and Google Scholar for predictive modelling studies applied to the outcome of prognosis for patients with PDAC post resection. Predictive modelling studies in this context included prediction model development studies with and without external validation and external validation studies with model updating. Data was extracted following the Checklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies (CHARMS) checklist. PRIMARY AND SECONDARY OUTCOME MEASURES:Primary outcomes were all components of the CHARMS checklist. Secondary outcomes included frequency of variables included across predictive models. RESULTS:263 studies underwent full text review. 15 studies met the inclusion criteria. 3 studies underwent external validation. Multivariable Cox proportional hazard regression was the most commonly employed modelling method (n=13). 10 studies were based on single centre databases. Five used prospective databases, seven used retrospective databases and three used cancer data registry. The mean number of candidate predictors was 19.47 (range 7 to 50). The most commonly included variables were tumour grade (n=9), age (n=8), tumour stage (n=7) and tumour size (n=5). Mean sample size was 1367 (range 50 to 6400). 5 studies reached statistical power. None of the studies reported blinding of outcome measurement for predictor values. The most common form of presentation was nomograms (n=5) and prognostic scores (n=5) followed by prognostic calculators (n=3) and prognostic index (n=2). CONCLUSIONS:Areas for improvement in future predictive model development have been highlighted relating to: general aspects of model development and reporting, applicability of models and sources of bias. TRIAL REGISTRATION NUMBER:CRD42018105942.

Project description:Published negative studies should have the same rigour of methodological quality as studies with positive findings. However, the methodological quality of negative versus positive studies is not known. The objective was to assess the reported methodological quality of positive versus negative studies published in Indian medical journals.A systematic review (SR) was performed of all comparative studies published in Indian medical journals with a clinical science focus and impact factor >1 between 2011 and 2013. The methodological quality of randomised controlled trials (RCTs) was assessed using the Cochrane risk of bias tool, and the Newcastle-Ottawa scale for observational studies. The results were considered positive if the primary outcome was statistically significant and negative otherwise. When the primary outcome was not specified, we used data on the first outcome reported in the history followed by the results section. Differences in various methodological quality domains between positive versus negative studies were assessed by Fisher's exact test.Seven journals with 259 comparative studies were included in this SR. 24% (63/259) were RCTs, 24% (63/259) cohort studies, and 49% (128/259) case-control studies. 53% (137/259) of studies explicitly reported the primary outcome. Five studies did not report sufficient data to enable us to determine if results were positive or negative. Statistical significance was determined by p value in 78.3% (199/254), CI in 2.8% (7/254), both p value and CI in 11.8% (30/254), and only descriptive in 6.3% (16/254) of studies. The overall methodological quality was poor and no statistically significant differences between reporting of methodological quality were detected between studies with positive versus negative findings.There was no difference in the reported methodological quality of positive versus negative studies. However, the uneven reporting of positive versus negative studies (72% vs 28%) indicates a publication bias in Indian medical journals with an impact factor of >1.

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Methodological quality of behavioural weight loss studies: a systematic review.

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Methodological quality of behavioural weight loss studies: a systematic review.

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