Results indicated that some PFTs may have some prognostic utility , i.e. a trend for more clinical events to be associated with groups classified as ' aspirin resistant ' .
Study -level effect sizes were generally small and absolute outcome risk was not substantially different between ' aspirin resistant ' and ' aspirin sensitive ' design ations .
Based on assumptions of PFTs being able to accurately identify patients at high risk of clinical events and such patients benefiting from treatment modification , the economic model found that a test-treat strategy was likely to be cost-effective .
However , neither assumption is currently evidence based .
BACKGROUND The use of aspirin is well established for secondary prevention of cardiovascular disease .
However , a proportion of patients suffer repeat cardiovascular events despite being prescribed aspirin treatment .
It is uncertain whether or not this is due to an inherent inability of aspirin to sufficiently modify platelet activity .
This report aims to investigate whether or not insufficient platelet function inhibition by aspirin ( ' aspirin resistance ' ) , as defined using platelet function tests ( PFTs ) , is linked to the occurrence of adverse clinical outcomes , and further , whether or not patients at risk of future adverse clinical events can be identified through PFTs .
OBJECTIVES To review systematic ally the clinical effectiveness and cost-effectiveness evidence regarding the association between PFT design ation of ' aspirin resistance ' and the risk of adverse clinical outcome ( s ) in patients prescribed aspirin therapy .
To undertake exploratory model-based cost-effectiveness analysis on the use of PFTs .
Reporting of prognostic markers: current problems and development of guidelines for evidence-based practice in the future
Prognostic markers help to stratify patients for treatment by identifying patients with different risks of outcome ( e.g. recurrence of disease ) , and are important tools in the management of cancer and many other diseases . Systematic review and meta-analytical approaches to identifying the most valuable prognostic markers are needed because ( sometimes conflicting ) evidence relating to markers is often published across a number of studies . To investigate the practicality of this approach , an empirical investigation of a systematic review of  tumour markers for neuroblastoma was performed ; 260 studies of prognostic markers were identified , which considered 130 different markers . The reporting of these studies was often inadequate , in terms of both statistical analysis and presentation , and there was considerable heterogeneity for many important clinical /statistical factors . These problems restricted both the extraction of data and the meta- analysis of results from the primary studies , limiting feasibility of the evidence -based approach . Guidelines for reporting the results of primary prognostic marker studies in cancer , and other diseases , are given in order to facilitate both the interpretation of individual studies and the undertaking of systematic review s , meta- analysis and , ultimately , evidence -based practice . General availability of full individual patient data is a necessary step forward and would overcome the majority of problems encountered , including poorly reported summary statistics and variability in cutoff level , outcome assessed and adjustment factors used . It would also limit the problem of reporting bias , although publication bias will remain a concern until studies are prospect ively registered . Such changes in practice would help important evidence -based review s to be conducted in order to establish the most appropriate prognostic markers for clinical use , which should ultimately improve patient care
Results indicated that some PFTs may have some prognostic utility , i.e. a trend for more clinical events to be associated with groups classified as ' aspirin resistant ' .
Study -level effect sizes were generally small and absolute outcome risk was not substantially different between ' aspirin resistant ' and ' aspirin sensitive ' design ations .
Based on assumptions of PFTs being able to accurately identify patients at high risk of clinical events and such patients benefiting from treatment modification , the economic model found that a test-treat strategy was likely to be cost-effective .
However , neither assumption is currently evidence based .
BACKGROUND The use of aspirin is well established for secondary prevention of cardiovascular disease .
However , a proportion of patients suffer repeat cardiovascular events despite being prescribed aspirin treatment .
It is uncertain whether or not this is due to an inherent inability of aspirin to sufficiently modify platelet activity .
This report aims to investigate whether or not insufficient platelet function inhibition by aspirin ( ' aspirin resistance ' ) , as defined using platelet function tests ( PFTs ) , is linked to the occurrence of adverse clinical outcomes , and further , whether or not patients at risk of future adverse clinical events can be identified through PFTs .
OBJECTIVES To review systematic ally the clinical effectiveness and cost-effectiveness evidence regarding the association between PFT design ation of ' aspirin resistance ' and the risk of adverse clinical outcome ( s ) in patients prescribed aspirin therapy .
To undertake exploratory model-based cost-effectiveness analysis on the use of PFTs .