Patients with chronic heart failure who agree to take part in clinical trials have a better prognosis than those who do not, according to a study reported in the November European Journal of Heart Failure.(1) The finding, say the authors, may even call into question the commonplace ethical requirement of most clinical trials that by choosing not to take part in the study a patient will not be disadvantaged.

The study was a follow-up of 2332 consecutive patients diagnosed with chronic heart failure at Castle Hill Hospital, Hull, UK. At their initial visit to the clinic all were asked if they would be willing to take part in clinical research projects. After a median follow-up of 55.7 months, analysis of the full cohort showed that 792 (34%) had died. However, survival was significantly associated with a willingness to take part in clinical trials, which more than halved the risk of death (hazard ratio 0.33).

The authors note that outcomes for patients with chronic heart failure are generally very poor; epidemiological studies show that around 40% of patients diagnosed with chronic heart failure die within a year of diagnosis.(2) "However," says investigator Dr Andrew Clark from Castle Hill Hospital, "two-year mortality rate in recent trials of chronic heart failure trials has been in the order of 20%. And even in studies of very sick patients, mortality has only been 30%. So we wanted to see if taking part in a clinical trial was associated with a beneficial outcome."

Additionally, to explore the effect on survival of actually entering a clinical trial (rather than simply indicating a willingness to take part) survival after the first year was compared between "willing" patients who were recruited to a trial and willing patients who were not.

The single most powerful predictor of all-cause mortality in the whole cohort (p