Commonalities among dietary recommendations from 2010-2021 clinical practice guidelines: A meta-epidemiological study from the American College of Lifestyle Medicine

Clinical practice guidelines (CPGs) provide recommendations to clinicians based on current medical knowledge to guide and reduce variability in clinical care. With advances in nutrition science research, CPGs increasingly include dietary guidance; however, the degree of consistency in dietary recommendations across CPGs has not been investigated. Using a systematic review approach adapted for meta-epidemiological research, this study compared dietary guidance from current guidelines developed by governments, major medical professional societies, and large health stakeholder associations due to their often well-defined and standardized processes for guideline development. CPGs making recommendations for dietary patterns and food groups or components for generally healthy adults or those with pre-specified chronic diseases were eligible. Literature from January 2010-2022 was searched in five bibliographic databases and augmented by searches in point-of-care resource databases and relevant websites. Reporting followed an adapted Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement and included narrative synthesis and summary tables. The protocol was pre-published on PROSPERO (CRD42021226281). Seventy-eight CPGs for major chronic conditions (autoimmune=7, cancers=5, cardiovascular-related=35, digestive=11, diabetes=12, weight-related=4, or multiple=3) and general health promotion (n=1) were included. Nearly all (91%) made dietary pattern recommendations, and roughly half (49%) endorsed patterns centered around plant foods. Overall, CPGs were most closely aligned in promoting consumption of major plant food groups (vegetables=74% of CPGs, fruit=69%, whole grains=58%) while discouraging intake of alcohol (62%) and salt or sodium (56%). CVD and diabetes CPGs were similarly aligned with additional messaging to consume legumes/pulses (60% of CVD CPGs; 75%, diabetes), nuts and seeds (67%, CVD), and low-fat dairy (60%, CVD). Diabetes guidelines discouraged sweets/added sugars (67%) and sweetened beverages (58%). This alignment across CPGs should boost clinician confidence in relaying such dietary guidance to patients in accordance with their relevant CPGs.

Evaluating Concordance of Bodies of Evidence from Randomized Controlled Trials, Dietary Intake, and Biomarkers of Intake in Cohort Studies: A Meta-Epidemiological Study

We aimed to identify and compare empirical data to determine the concordance of diet-disease effect estimates of bodies of evidence (BoE) from randomized controlled trials (RCTs), dietary intake, and biomarkers of dietary intake in cohort studies (CSs). The Cochrane Database of Systematic Reviews and MEDLINE were searched for systematic reviews (SRs) of RCTs and SRs of CSs that investigated both dietary intake and biomarkers of intake published between 1 January 2010 and 31 December 2019. For matched diet-disease associations, the concordance between results from the 3 different BoE was analyzed using 2 definitions: qualitative (e.g., 95% CI within a predefined range) and quantitative (test hypothesis on the z score). Moreover, the differences in the results coming from BoERCTs, BoECSs dietary intake, and BoECSs biomarkers were synthesized to get a pooled ratio of risk ratio (RRR) across all eligible diet-disease associations, so as to compare the 3 BoE. Overall, 49 diet-disease associations derived from 41 SRs were identified and included in the analysis. Twenty-four percent, 10%, and 39% of the diet-disease associations were qualitatively concordant comparing BoERCTs with BoECSs dietary intake, BoERCTs with BoECSs biomarkers, and comparing both BoE from CSs, respectively; 88%, 69%, and 90% of the diet-disease associations were quantitatively concordant comparing BoERCTs with BoECSs dietary intake, BoERCTs with BoECSs biomarkers, and comparing both BoE from CSs, respectively. The pooled RRRs comparing effects from BoERCTs with effects from BoECSs dietary intake were 1.09 (95% CI: 1.06, 1.13) and 1.18 (95% CI: 1.10, 1.25) compared with BoECSs biomarkers. Comparing both BoE from CSs, the difference in the results was also small (RRR: 0.92; 95% CI: 0.88, 0.96). Our findings suggest that BoE from RCTs and CSs are often quantitatively concordant. Prospective SRs in nutrition research should include, whenever possible, BoE from RCTs and CSs on dietary intake and biomarkers of intake to provide the whole picture for an investigated diet-disease association.

What is the influence of randomisation sequence generation and allocation concealment on treatment effects of physical therapy trials? A meta-epidemiological study

OBJECTIVE

To determine if adequacy of randomisation and allocation concealment is associated with changes in effect sizes (ES) when comparing physical therapy (PT) trials with and without these methodological characteristics.

DESIGN

Meta-epidemiological study.

PARTICIPANTS

A random sample of randomised controlled trials (RCTs) included in meta-analyses in the PT discipline were identified.

INTERVENTION

Data extraction including assessments of random sequence generation and allocation concealment was conducted independently by two reviewers. To determine the association between sequence generation, and allocation concealment and ES, a two-level analysis was conducted using a meta-meta-analytic approach.

PRIMARY AND SECONDARY OUTCOME MEASURES

association between random sequence generation and allocation concealment and ES in PT trials.

RESULTS

393 trials included in 43 meta-analyses, analysing 44,622 patients contributed to this study. Adequate random sequence generation and appropriate allocation concealment were accomplished in only 39.7% and 11.5% of PT trials, respectively. Although trials with inappropriate allocation concealment tended to have an overestimate treatment effect when compared with trials with adequate concealment of allocation, the difference was non-statistically significant (ES=0.12; 95% CI -0.06 to 0.30). When pooling our results with those of Nuesch et al, we obtained a pooled statistically significant value (ES=0.14; 95% CI 0.02 to 0.26). There was no difference in ES in trials with appropriate or inappropriate random sequence generation (ES=0.02; 95% CI -0.12 to 0.15).

CONCLUSIONS

Our results suggest that when evaluating risk of bias of primary RCTs in PT area, systematic reviewers and clinicians implementing research into practice should pay attention to these biases since they could exaggerate treatment effects. Systematic reviewers should perform sensitivity analysis including trials with low risk of bias in these domains as primary analysis and/or in combination with less restrictive analyses. Authors and editors should make sure that allocation concealment and random sequence generation are properly reported in trial reports.

How should we evaluate the risk of bias of physical therapy trials?: a psychometric and meta-epidemiological approach towards developing guidelines for the design, conduct, and reporting of RCTs in Physical Therapy (PT) area: a study protocol

BACKGROUND

Numerous tools and items have been developed in all health areas to assess the risk of bias of randomized controlled trials (RCTs). The Cochrane Collaboration (CC) released a new tool to assess bias in RCTs, based on empirical evidence quantifying the association between some design features and estimates of treatment effects (TEs). However, this evidence is limited to medicine and investigating a selected set of components. No such studies have been conducted in other health areas such as Physical Therapy (PT) and allied health professions. Evidence specific to the PT area is needed to understand and quantify the association between design features and TE estimates to inform practice and decision-making in this field. The overall goal of this project is to provide direction for the design, conduct, reporting and bias assessment of PT RCTs. We will achieve this through the following specific objectives and methods.

METHODS/DESIGN

1) to measure the association between methodological components and other factors (for example, PT area, type of intervention, type of outcomes) and TE estimates in RCTs in PT, 40 randomly selected meta-analyses of RCTs involving PT interventions will be identified from the Cochrane Database of Systematic Reviews. Trials will be evaluated independently by two reviewers using the most commonly used tools in the PT field. A two-level analysis will be conducted using a meta-meta-analytic approach; 2) to identify relevant items to evaluate risk of bias of PT trials, an exploratory factor analysis (EFA) will be used to identify the latent structure of the items; 3) to develop guidelines for the design, conduct, reporting, and risk of bias assessment of PT RCTs, items obtained from the factor analysis and the meta-epidemiological approach will be further evaluated by experts in PT through a web-based survey following a Delphi procedure.

DISCUSSION

The results of this project will have a direct impact on research and practice in PT and are valuable to a number of stakeholders: researchers when designing, conducting, and reporting trials; systematic reviewers and meta-analysts when synthesizing trial results; physiotherapists when making day-to-day treatment decision; and, other healthcare decision-makers, such as those developing policy or practice guidelines.