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The majority of cardiovascular randomized controlled trials (RCTs) test interventions in selected patient populations under explicitly protocol-defined settings. Although these 'explanatory' trial designs optimize conditions to test the efficacy and safety of an intervention, they limit the generalizability of trial findings in broader clinical settings. The concept of 'pragmatism' in RCTs addresses this concern by providing counterbalance to the more idealized situation underpinning explanatory RCTs and optimizing effectiveness over efficacy. The central tenets of pragmatism in RCTs are to test interventions in routine clinical settings, with patients who are representative of broad clinical practice, and to reduce the burden on investigators and participants by minimizing the number of trial visits and the intensity of trial-based testing. Pragmatic evaluation of interventions is particularly important in cardiovascular diseases, where the risk of death among patients has remained fairly stable over the past few decades despite the development of new therapeutic interventions. Pragmatic RCTs can help to reveal the 'real-world' effectiveness of therapeutic interventions and elucidate barriers to their implementation. In this Review, we discuss the attributes of pragmatism in RCT design, conduct and interpretation as well as the general need for increased pragmatism in cardiovascular RCTs. We also summarize current challenges and potential solutions to the implementation of pragmatism in RCTs and highlight selected ongoing and completed cardiovascular RCTs with pragmatic trial designs.

Background Several cancer therapies have been associated with cardiovascular harm in early-phase clinical trials. However, some cardiovascular harms do not manifest until later-phase trials. To limit interdisease variability, we focused on breast cancer. Thus, we assessed the reporting of cardiovascular safety monitoring and outcomes in phase 2 and 3 contemporary breast cancer clinical trials. Methods and Results We searched Embase and Medline records for phase 2 and 3 breast cancer pharmacotherapy trials. We examined exclusion criterion as a result of cardiovascular conditions, adverse cardiovascular event reporting, and cardiovascular safety assessment through cardiovascular imaging, ECG, troponin, or natriuretic peptides. Fisher's exact test was utilized to compare reporting. Fifty clinical trials were included in our study. Patients were excluded because of cardiovascular conditions in 42 (84%) trials. Heart failure was a frequent exclusion criterion (n=31; 62% trials). Adverse cardiovascular events were reported in 43 (86%) trials. Cardiovascular safety assessments were not reported in 23 (46%) trials, whereas natriuretic peptide and troponin assessments were not reported in any trial. Cardiovascular safety assessments were more frequently reported in industry-funded trials (69.2% versus 0.0%; P

AimsRecent trials have evaluated sodium-glucose co-transporter 2 inhibitors in patients with heart failure (HF). We sought to assess the robustness of findings from these trials using the fragility index (FI).Methods and resultsFragility index is defined as the minimum number of patients that must be moved from the 'non-event' to the 'event' group to turn a statistically significant result to non-significant. In addition to FI, fragility quotient [(FQ); FI divided by the sample size] was calculated to assess the proportion of events that must be moved to change the significance. For statistically non-significant outcomes, reverse fragility index (RFI) and reverse fragility quotient (RFQ) were calculated. Robustness of findings after pooling data from all three trials was also assessed. A robust reduction in first HF hospitalization or cardiovascular mortality was seen with dapagliflozin (FI = 62 and FQ = 0.013), empagliflozin (FI = 50 and FQ = 0.013), and sotagliflozin (FI = 60 and FQ = 0.049). Dapagliflozin nominally improved all-cause and cardiovascular mortality, with modest FI (n = 8 and 5) and FQ (0.002 and 0.001). Empagliflozin and sotagliflozin did not demonstrate statistically significant reductions in all-cause mortality, with modest RFI (empagliflozin: RFI = 26 and RFQ = 0.007; sotagliflozin: RFI = 6 and RFQ = 0.005). A similar trend was seen with cardiovascular mortality (empagliflozin: RFI = 24 and RFQ = 0.006; sotagliflozin: RFI = 7 and RFQ = 0.006). Upon meta-analysis, the result for first HF hospitalization or cardiovascular mortality was robust (FI = 95 and FQ = 0.010). The reductions in all-cause (FI = 12 and FQ = 0.001) and cardiovascular mortality (FI = 9 and FQ = 0.001), while statistically significant, were fragile.ConclusionImprovement in the composite outcome of first HF hospitalization or cardiovascular death was highly concordant and robust across sodium-glucose co-transporter 2 inhibitor trials. In contrast, secondary endpoints of all-cause and cardiovascular mortality were statistically fragile, underscoring the need to power trials for mortality to fully understand the benefit of therapies on fatal events.

BackgroundRepresentation trends of women, older adults, and ethnic/racial minorities in randomized controlled trials (RCTs) of atrial fibrillation (AF) are uncertain.MethodsWe systematically reviewed 134 AF related RCTs (phase II and III) encompassing 149,162 participants using Medline and ClinicalTrials.gov through April 2019 to determine representation trends of women, older patients (≥75 years), and ethnic/racial minorities. Weighted data on the prevalence of AF from epidemiological studies were used to compare the representation of the studied groups of interest in AF RCTs to their expected burden of the disease.ResultsOnly 18.7% of the RCTs reported proportion of older patients, and 12.7% RCTs reported ethnic/racial minorities. The proportions of women in RCTs versus general population were 35.2% and 35.1%, of Hispanics were 11.9% and 5.2%, of Blacks were 1.2% and 5.7%, of American Indian/Alaskans were 0.2% and 0.2%, of Asians were 14.2% and 2.4%, of native Hawaiian/Pacific Islanders were 0.05% and 0.1% and of non-Whites were 19.5% and 22.5%, respectively. The weighted mean age (SD) across the trials was 65.3 (3.2) years which was less than the corresponding weighted mean age of 71.1 (4.5) years in the comparative epidemiological data.ConclusionThe reporting of older patients and ethnic/racial minorities was poor in RCTs of AF. The representation of women and American Indian/Alaskan natives matched their expected population share of disease burden. Hispanics and Asians were over-represented and Blacks, native Hawaiian/Pacific Islanders and non-Whites were under-represented in RCTs of AF.

AimsDiscontinuation or non-publication of trials may hinder scientific progress and violates the commitment made to research participants. We sought to identify the prevalence of discontinuation and non-publication of heart failure (HF) clinical trials.Methods and resultsWe conducted a cross-sectional search of ClinicalTrials.gov to identify all completed and discontinued HF clinical trials. We limited our search to only include trials that were completed by 31 December 2017. Trials were investigated to identify reasons for discontinuation. Informative termination was defined as trial termination due to safety or efficacy concerns. Data pertaining to the trial phase, funding, intervention, enrolment, and trial completion date were extracted for each trial. A total of 572 trials were included. Of these, 21% (n = 118) were discontinued before completion. Patient accrual was the most frequently cited reason (n = 42; 36%) for trial discontinuation, followed by informative termination (n = 16; 14%) and funding (n = 14; 12%). Overall, 24 780 patients were enrolled in trials that were terminated. Of trials that were completed and not terminated, nearly one-third (n = 131/454; 29%) were not published. Seventy-nine (24%) trials were published within 12 months, 192 (59%) within 24 months, and 252 (78%) trials within 36 months.ConclusionsDiscontinuation and non-publication of HF trials is common. This raises ethical concerns towards participants who volunteer for research and are exposed to potential risks, inconvenience, and discomfort without furthering scientific progress.

AimsThis study aimed to investigate the reporting of subgroup analyses in heart failure (HF) randomized controlled trials (RCTs) and to determine the strength and credibility of subgroup claims.Methods and resultsAll primary HF RCTs published in nine high-impact journals from 1 January 2008 to 31 December 2017 were included. Multivariable regression analysis was used to identify factors that may favour the reporting of results in specific subgroups. Strength of the subgroup effect claimed was classified into (i) strong, (ii) likely, or (iii) suggestive. Credibility of subgroup claim was scored using a pre-specified 10 pointer criteria. Of the 261 HF RCTs studied, 107 (41%) reported subgroup analyses. Twenty-five (23%) RCTs claimed a subgroup effect for the primary outcome of which six (24%) made a strong claim, eight (32%) claimed a likely effect, and 11 (44%) suggested a possible subgroup effect. Seven of the 25 RCTs did not employ interaction testing for subgroup claims of the primary outcome. Three out of 10 pre-specified credibility criteria were satisfied by half of the trials. Fourteen trials justified the choice of subgroups, and 10 explicitly stated they were underpowered to detect differences within subgroups. Source of funding did not influence the frequency of reporting subgroup analyses (OR 0.53, 95% CI 0.78-3.62, P = 0.52).ConclusionsAppropriate credibility criteria were rarely met even by HF RCTs that held strong subgroup claims. Subgroup analyses should be pre-specified, be adequately powered, present interaction terms, and be replicated in independent data before being integrated into clinical decision making.