Outcome selection and role of patient reported outcomes in contemporary cardiovascular trials: systematic review

OBJECTIVES: To systematically assess the type of outcomes selected and the prevalence of patient reported outcomes in contemporary cardiovascular trials and to quantify any misuse or underuse of patient reported outcomes using a specially developed tool that would allow estimation of the relevance of such outcomes to clinical decision making.

DESIGN: Systematic review.

DATA SOURCES: Medline and Embase.

STUDY SELECTION: Randomised controlled trials of the treatment for or prevention of cardiovascular disease published in 10 leading general medical and cardiology journals from January 2005 to December 2008.

RESULTS: Primary outcomes were patient important (death, morbidity, or patient reported outcomes) in only 93 of 413 trials (23%, SE 2%), whereas another 92 (22%, SE 2%) combined these outcomes with other less important ones into a composite. Sixty five trials (16%; SE 2%) used at least one instrument to measure patient reported outcomes, mostly in trials where such information would have been important or crucial for clinical decision making (52 trials). Patient reported outcomes were judged to be of little incremental value to a large number of, mostly explanatory, cardiovascular trials (152 trials). However, many trials in which patient reported outcomes would have been important or crucial for clinical decision making did not report such outcomes (122 of 174 trials, 70%). These included several trials that primarily aimed to improve symptoms or functional status, trials that tested interventions with a considerable potential for causing harm (mainly bleeding) that were not meaningfully measured, and trials with composite outcomes that were dominated by outcomes of questionable importance to patients.

CONCLUSIONS: Despite a continued rise in the reporting of patient reported outcomes with no evidence for their misuse in more recent cardiovascular trials, they seem to be still underused once their relevance to clinical decision making has been taken into account. This was largely explained by inappropriate use of composite outcomes and inadequate measurement of harms.