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Proposal 1071

Title of the Proposed Research

Optimising the Analysis of vascular Prevention trials (OA-Prevention)

Lead Researcher

Professor Philip Bath


University of Nottingham

Funding Source

Institutional funding

Potential Conflicts of Interest

Potential conflicts of interest will be disclosed when the research is presented and published.

Data Sharing Agreement Date

1 July 2015

Lay Summary

Prevention trials typically count outcomes as dichotomous events (e.g. stroke – no stroke) although this is inefficient statistically and gives no indication on the severity of recurrent events. We hypothesise that vascular events may be polychotomised with ordering determined by severity, e.g. stroke categorised as fatal-severe-mild-TIA-no stroke. In a pilot study using published summary trial data, ordinal analysis of these ordered categorical outcomes was more efficient statistically than current binary approaches. We plan to further test this concept using individual patient data from vascular prevention trials, not least because many publications do not provide sufficient granular data. We will identify relevant trials and generate ordered vascular outcomes. We will then compare binary and ordinal statistical methods of analysis, both unadjusted and adjusted, then compare sample size estimates and number-needed-to-treat for these trials using published binary and ordinal methods. If these ordinal approaches are superior, future trials should consider using stroke and other vascular outcomes as ordered categories, and should be analysed using ordinal (or even linear) statistical tests. Using this approach, future trials could potentially be smaller (thereby reducing trial costs and competition for patient recruitment) and provide extra information on the effect of treatment on the severity, as well as frequency of vascular events. This information will be vital for patients, carers, healthcare professionals, and Government.

Study Data Provided

Study AR2103413: An International Randomized Study Evaluating the Efficacy and Safety of Fondaparinux Versus Control Therapy in a Broad Range of Patients With ST Segment Elevation Acute Myocardial Infarction.
Study AR3103414: A multicenter, randomized, double-blind, parallel group trial to demonstrate the efficacy of fondaparinux sodium in association with Intermittent Pneumatic Compression (IPC) versus IPC used alone for the prevention of venous thromboembolic events in subjects at increased risk undergoing major abdominal surgery
Study 9.178: JASAP: Japanese Aggrenox Stroke Prevention vs. Aspirin Programme
Study 9.159: PRoFESS - Prevention Regimen For Effectively Avoiding Second Strokes

Statistical Analysis Plan

The statistical analysis plan will be added after the research is published.

Publication Citation