The use of interim data and Data Monitoring Committee recommendations in randomized controlled trial reports: frequency, implications and potential sources of bias

Background: Interim analysis of accumulating trial data is important to protect participant safety during randomized controlled trials (RCTs). Data Monitoring Committees (DMCs) often undertake such analyses, but their widening role may lead to extended use of interim analysis or recommendations that could potentially bias trial results.Methods: Systematic search of eight major publications: Annals of Internal Medicine, BMJ, Circulation, CID, JAMA, JCO, Lancet and NEJM, including all randomised controlled trials ( RCTs) between June 2000 and May 2005 to identify RCTs that reported use of interim analysis, with or without DMC involvement. Recommendations made by the DMC or based on interim analysis were identified and potential sources of bias assessed. Independent double data extraction was performed on all included trials.Results: We identified 1772 RCTs, of which 470 (27%; 470/1772) reported the use of a DMC and a further 116 (7%; 116/1772) trials reported some form of interim analysis without explicit mention of a DMC. There were 28 trials ( 24 with a formal DMC), randomizing a total of 79396 participants, identified as recommending changes to the trial that may have lead to biased results. In most of these, some form of sample size re-estimation was recommended with four trials also reporting changes to trial endpoints. The review relied on information reported in the primary publications and methods papers relating to the trials, higher rates of use may have occurred but not been reported.Conclusion: The reported use of interim analysis and DMCs in clinical trials has been increasing in recent years. It is reassuring that in most cases recommendations were made in the interest of participant safety. However, in practice, recommendations that may lead to potentially biased trial results are being made

An assessment of the cost-effectiveness of magnetic resonance, including diffusion-weighted imaging in patients with transient ischaemic attack and minor stroke : a systematic review, meta-analysis and economic evaluation

Erratum issued September 2015 Erratum DOI: 10.3310/hta18270-c201509Peer reviewedPublisher PD

European research priorities for intracerebral haemorrhage

Over 2 million people are affected by intracerebral haemorrhage (ICH) worldwide every year, one third of them dying within 1 month, and many survivors being left with permanent disability. Unlike most other stroke types, the incidence, morbidity and mortality of ICH have not declined over time. No standardised diagnostic workup for the detection of the various underlying causes of ICH currently exists, and the evidence for medical or surgical therapeutic interventions remains limited. A dedicated European research programme for ICH is needed to identify ways to reduce the burden of ICH-related death and disability. The European Research Network on Intracerebral Haemorrhage EURONICH is a multidisciplinary academic research collaboration that has been established to define current research priorities and to conduct large clinical studies on all aspects of ICH. Copyright (C) 2011 S. Karger AG, Base

Stroke prevention using the oral direct thrombin inhibitor ximelagatran inpatients with nonvalvular atrial fibrillation. Pooled analysis from the SPORTIF III ad V studies.

Background: To show results of a prespecified pooled analysis of the studies SPORTIF III (open-label) and SPORTIF V (double-blind), to assess the homogeneity of the results and to explore subgroup analyses and adverse events. Methods and Results: 7,329 patients with atrial fibrillation (AF) and 1 additional stroke risk factor were randomized to warfarin (international normalized ratio 2.0-3.0) or ximelagatran (36 mg twice daily). Over 11,346 patient-years (mean 18.5 months/patient), 184 patients developed primary events of stroke and systemic embolism (ximelagatran 1.62 vs. warfarin 1.65%/year; p = 0.94). Heterogeneity between trials with respect to the primary event rate (study-by-treatment interaction p = 0.026) was found. This could not be explained statistically by baseline patient characteristics or by treatment (except perhaps by the better anticoagulation with warfarin in SPORTIF V) and was not evident for secondary end-points. There was no conclusive difference in major bleeding rates (ximelagatran 1.88 vs. warfarin 2.46%/year; p = 0.054), but combined minor plus major bleeding was lower with ximelagatran (31.7 vs. 38.7%/year; p < 0.0001). Elevation of liver enzymes occurred more frequently in patients taking ximelagatran (6.1% vs. warfarin 0.8%; p < 0.0001) and was reversible except in rare cases. Conclusions: Fixed-dose oral ximelagatran without coagulation monitoring prevented stroke and systemic embolism as effectively as warfarin in patients with AF. Differences in the results of the two trials might relate to consistency of warfarin anticoagulation, different degree of blinding in the two trials, other concomitant therapies or chance. Further investigation is required to explore the long-term safety profile of ximelagatran