Recommendations and levels of evidence in the guidelines of the European Society of Cardiology: current scenario and time trends

Correlation between the level of evidence and the class of recommendations concerning the pharmacological aspects of the Guidelines of the European Society of Cardiology

Background The reliability of the recommendations affecting the clinical decisions is being continuously weighed in everyday practice (Gershlick, 2018). The objective of our study was to assess the consistency of the evidence behind the recommendations. Methods We narrowed our focus on the pharmacotherapeutic aspects of the most recent 38 European Society of Cardiology guidelines and analyzed the correlation between the level of evidence (LoE) classified as A, B and C and the class of recommendations (CoR) subdivided into I, IIa, IIb and III. Results Contrary to the majority of recommendations based on a LoE C (43,0%), fewer recommendations were proposed on heavily evidence-supported LoE A (23.8%), which percentage increased with subsequent updates of the guidelines. The most common recommendation was CoR I (44,9%), while the least common recommendation was CoR III (9,2%). While a similar share of A (39,1%) and C (30,1%) LoE shaped the CoR I nearly half (48,8%) of the CoR III were based on LoE C. Conversely, the overwhelming majority of the recommendations within the scope of LoE A were indisputably strong and classified as CoR I (73,7%). Conclusion The pharmacological aspects of the ESC guidelines are predominantly based on LoE C. A greater number of pharmacological recommendations are based on LoE A in comparison to the general ones. Various constraints significantly skew the credibility due to paucity of scientific data. A more nuanced approach is needed, as the guidelines cannot completely substitute the clinical experience and the patient-centered approach in shaping the optimal therapeutic outcome.

Antithrombotic Therapy Recommendations in the European Society of Cardiology Guidelines: How Robust Are the Randomized Controlled Trials Underpinning Them?

Introduction  Criticisms have been raised against the sole use of p -value in interpreting results from randomized controlled trials (RCTs). Additional tools have been suggested, like the fragility index (FI), a measure of a trial's robustness/fragility, and derivative measures. The FI is the minimum number of patients who would have to be converted from nonevents to events, in the group with the least events, for a result to lose statistical significance. Objective  This study aimed to evaluate RCT supporting European Society of Cardiology (ESC) guidelines regarding antithrombotics, using the FI and FI-related measures. Methods  FI, fragility quotient (FQ), and FI minus LTF lost to follow-up (FI - LTF) were calculated for the RCT underpinning recommendations regarding antithrombotic therapy from the updated ESC guidelines. LTF was compared with FI. Results were calculated for the total group of studies, as per guideline and as per recommendation type. Results  Overall, 61 studies were included. The median FI was 24.5 (interquartile range [IQR]: 9.0-60.0) and median FQ was 0.0035 (IQR: 0.0019-0.0056). Median FI - LTF was 2.0 (IQR: 0.0-38.0). Twenty (32.8%) of the studies had one primary or main safety outcome with LTF exceeding FI. Peripheral arterial disease guideline and chronic coronary syndrome guideline had the lowest (2.5; IQR: 1.8-3.3) and the highest (48.5; IQR: 23.8-73.0) FI, respectively. Conclusion  The median FI suggests robustness of clinical trials evaluating antithrombotic drugs cited in the guidelines, but about one-third of them had LTF larger than FI. This emphasizes the need for assessing trials' robustness when constructing guidelines.

Effect of oxygen supply on mortality in acute ST-elevation myocardial infarction: systematic review and meta-analysis

Previous studies stated that high oxygen supply in patients with myocardial infarction (MI) was not associated with improved outcomes. However, the particularities of ST-elevation myocardial infarction (STEMI) and the results of a recent trial raised the question if this subgroup of patients benefits from high oxygen supply. This study aims to evaluate the clinical effect of high oxygen supply in patients with STEMI using a systematic review of the available literature. All randomized controlled trials (RCTs) evaluating the systematic use of high oxygen (6 L/min or higher) versus room air or lower oxygen supply in STEMI patients were included. Systematic review with meta-analysis of trials retrieved in July 2020. Six databases were searched. The confidence in the pooled estimates was ascertained through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Risk of bias was evaluated using the Cochrane risk of bias tool. There were five eligible RCTs (7703 patients). High oxygen supply was associated with a significant risk reduction of short-term mortality [risk ratio (RR) 0.83; 95% confidence interval (CI), 0.70-0.98; I2 = 0%]. Mortality (longest follow-up) (RR 0.83; 95% CI, 0.71-0.97; I2 = 0%) and heart failure (RR 0.84; 95% CI, 0.60-1.18; I2 = 0%) did not present a risk reduction. Recurrent MI presented a contradictory result, favouring the lower oxygen protocol (RR 1.47; 95% CI, 0.84-2.56; I2 = 0%). The GRADE analysis was very low. High oxygen supply may be associated with a decrease in short-term mortality in STEMI patients, but the pooled data are not robust enough to allow definitive conclusions.