Are Surgical Trials with Negative Results Being Interpreted Correctly?

BACKGROUND: Many published accounts of clinical trials report no differences between the treatment arms, while being underpowered to find differences. This study determined how the authors of these reports interpreted their findings. STUDY DESIGN: We examined 54 reports of surgical trials chosen randomly from a database of 110 influential trials conducted in 2008. Seven that reported having adequate statistical power (b 0.9) were excluded from further analysis, as were the 32 that reported significant differences between the treatment arms. We examined the remaining 15 to see whether the authors interpreted their negative findings appropriately. Appropriate interpretations discussed the lack of power and/or called for larger studies. RESULTS: Three of the 7 trials that did not report an a priori power calculation offered inappropriate interpretations, as did 3 of the 8 trials that reported an a priori power < 0.90. However, we examined only a modest number of trial reports from 1 year. CONCLUSIONS: Negative findings in underpowered trials were often interpreted as showing the equivalence of the treatment arms with no discussion of the issue of being underpowered. This may lead clinicians to accept new treatments that have not been validated

Sydney College of the Arts handbook

2002 handbook for Sydney College of the Arts (SCA

TCT-4 Efficacy and Safety of Concurrent Administration of Clopidogrel-loading (600mg) and Prasugrel-loading (60mg) in Patients with Acute ST-Segment Elevation Myocardial Infarction

Background: Current STEMI guideline recommendations limit the use of prasugrel to clopidogrel-naïve patients. However, in daily clinical practice a considerable proportion of STEMI patients undergoing primary PCI are preloaded with clopidogrel. Whether the use of prasugrel in clopidogrel pretreated STEMI patients is safe remains unknown. Similarly, the efficacy of a combined loading dose regimen has not been evaluated. Methods: Between 1 September 2009 and 15 October 2012, a total of 1,157 STEMI patients were included in the randomized COMFORTABLE AMI trial (NCT 00962416) and 891 STEMI patients in the SPUM ACS registry (NCT 01000701) at 12 centers. Patients were divided into three groups according to type of peri-procedural antiplatelet loading: (1) Clopidogrel and subsequent Prasugrel loading dose [CP], (2) Prasugrel loading dose alone [P] (3) Clopidogrel loading dose alone [C]; 23 patients were excluded because they were not exposed to Clopidogrel and Prasugrel. The primary safety endpoint was the rate of BARC type 3, 4 and 5 bleeding at 30 days. The primary efficacy endpoint was the composite of cardiac death, nonfatal MI and nonfatal stroke at 30 days. Outcomes were analyzed using Cox's Regressions (crude) and multinomial ITPW weighted Cox's Regressions. Results: A total of 2,025 patients were analysed of whom 428 (21.1%) had received CP, 447 (22.1%) patients P alone, and 1,150 (56.8%) patients C alone. The primary safety endpoint was observed among 1.2% of CP, 1.6% of P, and 1.5% of C patients (CP vs C ad. HR 0.99 (0.36-2.72), PC vs P ad. HR 0.73 (0.22-2.41). The primary safety endpoint occurred less frequently among CP (1.9%) compared with C patients (5.0%, adjusted HR 0.47 (0.22-1.00), but with similar frequency among P and C patients (2.9% vs 5.0%, ad. HR 0.68 (0.27-1.73). The net clinical benefit outcome parameter tended to be lower among CP (2.8%) compared with C patients (6.3%, ad. HR 0.56 (0.30-1.05), whereas no significant difference was observed between P and C patients (3.8% vs 6.3%, ad. HR 0.85 (0.39-1.86). Conclusions: Among STEMI patients preloaded with Clopidogrel, the concurrent administration of a Prasugrel loading dose appears safe and potentially more effective than Clopiogrel alone

Comparison of zotarolimus- and everolimus-eluting coronary stents: final 5-year report of the RESOLUTE all-comers trial

BACKGROUND Newer-generation drug-eluting stents that release zotarolimus or everolimus have been shown to be superior to the first-generation drug-eluting stents. However, data comparing long-term safety and efficacy of zotarolimus- (ZES) and everolimus-eluting stents (EES) are limited. RESOLUTE all-comers (Randomized Comparison of a Zotarolimus-Eluting Stent With an Everolimus-Eluting Stent for Percutaneous Coronary Intervention) trial compared these 2 stents and has shown that ZES was noninferior to EES at 12-month for the primary end point of target lesion failure. We report the secondary clinical outcomes at the final 5-year follow-up of this trial. METHODS AND RESULTS RESOLUTE all-comer clinical study is a prospective, multicentre, randomized, 2-arm, open-label, noninferiority trial with minimal exclusion criteria. Patients (n=2292) were randomly assigned to treatment with either ZES (n=1140) or EES (n=1152). Patient-oriented composite end point (combination of all-cause mortality, myocardial infarction, and any revascularizations), device-oriented composite end point (combination of cardiac death, target vessel myocardial infarction, and clinically indicated target lesion revascularization), and major adverse cardiac events (combination of all-cause death, all myocardial infarction, emergent coronary bypass surgery, or clinically indicated target lesion revascularization) were analyzed at 5-year follow-up. The 2 groups were well-matched at baseline. Five-year follow-up data were available for 98% patients. There were no differences in patient-oriented composite end point (ZES 35.3% versus EES 32.0%, P=0.11), device-oriented composite end point (ZES 17.0% versus EES 16.2%, P=0.61), major adverse cardiac events (ZES 21.9% versus EES 21.6%, P=0.88), and definite/probable stent thrombosis (ZES 2.8% versus EES 1.8%, P=0.12). CONCLUSIONS At 5-year follow-up, ZES and EES had similar efficacy and safety in a population of patients who had minimal exclusion criteria. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00617084

The variable functional effects of the pacing site in normal and scarred ventricles

The pacing site has been shown to influence functional improvement with cardiac resynchronization therapy. We evaluated the effects of the pacing site on left ventricular (LV) function in an animal model. Equilibrium radionuclide angiography was acquired in sinus rhythm (NSR) and with ventricular pacing, from three pacing sites in seven normal and eight infarcted dogs. QRS duration, electrical activation pattern, wall motion, LV ejection fraction (EF), synchrony of ventricular contraction, and mean arterial pressure (MAP), were related to the pacing site and infarct size, during each of 120 episodes. Little changed during pacing in normals. In infarcted dogs, LV wall motion, and synchrony worsened, LVEF and MAP often fell. These changes related to altered activation patterns which were influenced by the pacing site but were not related to infarct size. Hemodynamic and functional LV changes after infarction were found to vary with the pacing site and associated conduction and synchrony

Drug eluting and bare metal stents in people with and without diabetes: collaborative network meta-analysis

Objective To compare the effectiveness and safety of three types of stents (sirolimus eluting, paclitaxel eluting, and bare metal) in people with and without diabetes mellitus