ANM150 Jan AY2324 Week 3 Research 6 - GRADE (1) PDF

GRADING THE EVIDENCE CASE 5 ANM 150 Dr. Monique Aucoin ND MSc HOW DO WE WEIGH THE EVIDENCE? GRADE Grading of Recommendations, Assessment, Development and Evaluations Transparent framework for developing and presenting summaries of evidence Systematic approach to clinical decision making HOW...

GRADING THE EVIDENCE CASE 5 ANM 150 Dr. Monique Aucoin ND MSc HOW DO WE WEIGH THE EVIDENCE? GRADE Grading of Recommendations, Assessment, Development and Evaluations Transparent framework for developing and presenting summaries of evidence Systematic approach to clinical decision making HOW DOES IT WORK? Clinical question (PICO format) A systematic review provides an estimate of the effect size of an outcome Author rates the quality of the evidence and strength of recommendations  GRADE CERTAINTY RATING Certainty: whether an estimate of association or effect is correct or true Certainty What it means Very low The true effect is probably markedly different from the estimated effect Low The true effect might be markedly different from the estimated effect Moderate The authors believe that the true effect is probably close to the estimated effect High The authors have a lot of confidence that the true effect is similar to the estimated effect WHAT MAKES EVIDENCE LESS CERTAIN? (“RATE DOWN”) 1. Risk of bias 2. Imprecision 3. Inconsistency 4. Indirectness 5. Publication bias 1. RISK OF BIAS Bias → inherent limitation in the design of a study cause the results to be inaccurate Ex. Studies not randomized, randomized trials not blinded when they should be, loss to follow up of participants, observational studies not adjusted for important cofounders Many tools for assessing risk of bias in individual studies (vs GRADE assess the body of evidence as a whole) 2. IMPRECISION Are the results due to chance? In GRADE, focus on 95% confidence interval Ex. Few observed events (the outcome) or few participants in the studies can decrease precision and widen the confidence interval Certainty is lower if decision is different at upper/lower end of confidence interval Imprecision may be ‘rated down’ if there were few events 3. INCONSISTENCY Many similar studies showing a consistent effect increase certainty Assessed by comparing the results of individual studies (look at a forest plot!) Ex. Confidence intervals overlapping, difference in estimate of effect, formal tests for statistical heterogeneity 4. INDIRECTNESS Certainty is down rated when the intervention of interest is not studies in the population of interest and reporting the outcome of interest Ex. surrogate vs clinical outcome, is the studied intervention the exact intervention of interest (dosing, method of administration etc) vs treatment at a highly specialized facility 5. PUBLICATION BIAS Is this really all of the research evidence that exists? Ex. Only small studies that confirm investigators’ perceptions of the effect are available but additional studies were conducted, results that have not been published There are visual and statistical methods for assessing (Funnel Plot) WHAT MAKES EVIDENCE MORE CERTAIN? (“RATE UP”) Large magnitude of effect Dose-response gradient All residual confounding would increase our confidence in an effect Ex. A very large observational or non-randomized study without other limitations GRADE: 2 PARTS 1) Certainty of Evidence How likely is it that something works? All the factors we have considered so far: are the results consistent? Precise? Apply in this setting? Bias? 2) Recommendation Strength Should it be recommended for use (or not!) Consider Evidence + benefits/harms, equity, resources, feasibility, acceptability RECOMMENDATIONS Can be in favour or against an intervention Can be strong or weak If weak: likely to be variation in the decision made by informed people The weaker the recommendation: more essential the shared decision making process becomes LET’S SEE AN EXAMPLE! Asbaghi O, Salehpour S, Rezaei Kelishadi M, Bagheri R, Ashtary-Larky D, Nazarian B, Mombaini D, Ghanavati M, Clark CC, Wong A, Naeini AA. Folic acid supplementation and blood pressure: A GRADE-assessed systematic review and dose-response meta-analysis of 41,633 participants. Critical Reviews in Food Science and Nutrition. 2021 Aug 14:1-6. Abstract: Hypertension is a predisposing factor for cardiovascular disease (CVD). The extant literature regarding the effects of folic acid supplementation on blood pressure (BP) is inconsistent. Therefore, this systematic review and meta- analysis of randomized controlled trials was conducted to summarize the effects of folic acid supplementation on BP. A systematic search was carried out in PubMed, Scopus, ISI Web of Science, and Cochrane library, from database inception to August 2021. Data were pooled using the random-effects method and were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). The pooled results of 22 studies, including 41,633 participants, showed that folic acid supplementation significantly decreased systolic BP (SBP) (WMD: −1.10 mmHg; 95% CI: −1.93 to −0.28; p = 0.008). Subgroup analysis showed that the results remained significant when baseline SBP was ≥120 mmHg, intervention duration was ≤6 weeks, intervention dose was ≥5 mg/d, in patients with CVD, males and females, and overweight participants, respectively. Furthermore, the changes observed in diastolic BP (DBP) (WMD: −0.24 mmHg; 95% CI: −0.37 to −0.10; p < 0.001) were also statistically significant. However, subgroup analysis showed that the results remained significant in subject with elevated DBP, long term duration of intervention (>6 weeks), low dose of folic acid (