Is Taking Part in Clinical Trials Good for Your Health? A Cohort Study
Is Taking Part in Clinical Trials Good for Your Health? A Cohort Study
Aims: The prognosis of patients included in clinical trials is often better than might be anticipated from epidemiological data. Patients volunteering to take part in a study might be unrepresentative of the potential treatment population or the trial itself may confer benefit by offering closer supervision.
Methods and Results: A total of 2332 consecutive patients (average ± SD age 70.1 ± 10.8; 26% female) who presented to a community heart failure clinic were diagnosed as having heart failure due to left ventricular systolic dysfunction. All patients were asked whether they would be prepared to take part in clinical research projects at their initial visit. During a median follow-up in survivors of 55.7 months (interquartile range 30.4-74.3), 792 (34%) patients died. Agreeing to take part in clinical trials strongly predicted a good outcome (approximately halving the risk of death). In multivariate modelling, willingness to take part [hazard ratio (95% confidence intervals) 0.33 (0.26-0.40)] was a predictor of good outcome independent of age, severity of left ventricular dysfunction, renal function, sodium levels, drug use, and comorbidities. In a subset in whom N-terminal pro-B type natriuretic peptide (NT-proBNP) was available (n = 1256), agreeing to take part in trials remained an independent predictor of survival with log [NT-proBNP].
Conclusion: Those patients with chronic heart failure who express a willingness to take part in a clinical trial, appear to have a better prognosis than those who do not.
It is a commonplace requirement in applying for study approval from an Ethics Committee that an investigator has to specify that a patient will not be disadvantaged by choosing not to take part in the study. Indeed, an Ethics Committee would be very likely to turn down a study which declared otherwise as being unduly coercive. However, it is a familiar feature of clinical trials that the prognosis of patients included is, in general, better than might be anticipated from epidemiological data. For example, the 2 years mortality rate in recent chronic heart failure trials has been in the order of 20%, and even in studies of very sick heart failure patients, mortality has only been ~30%. In contrast, data from epidemiological studies suggest that ~40% of people die within a year of diagnosis of heart failure and that survival is worse than for many forms of cancer.
There are a number of possible reasons: patients volunteering to take part in a study might be unrepresentative of the potential treatment population, for example, they may be on average younger, have milder disease and have a positive response to their disease; the study design may exclude patients with more severe disease, complications, or co-morbidities; and the trial itself may confer benefit by offering closer medical and nursing supervision by interested specialists than might otherwise be the case.
We wanted to see if taking part in a clinical trial was associated with a beneficial outcome in patients with chronic heart failure.
Abstract and Introduction
Abstract
Aims: The prognosis of patients included in clinical trials is often better than might be anticipated from epidemiological data. Patients volunteering to take part in a study might be unrepresentative of the potential treatment population or the trial itself may confer benefit by offering closer supervision.
Methods and Results: A total of 2332 consecutive patients (average ± SD age 70.1 ± 10.8; 26% female) who presented to a community heart failure clinic were diagnosed as having heart failure due to left ventricular systolic dysfunction. All patients were asked whether they would be prepared to take part in clinical research projects at their initial visit. During a median follow-up in survivors of 55.7 months (interquartile range 30.4-74.3), 792 (34%) patients died. Agreeing to take part in clinical trials strongly predicted a good outcome (approximately halving the risk of death). In multivariate modelling, willingness to take part [hazard ratio (95% confidence intervals) 0.33 (0.26-0.40)] was a predictor of good outcome independent of age, severity of left ventricular dysfunction, renal function, sodium levels, drug use, and comorbidities. In a subset in whom N-terminal pro-B type natriuretic peptide (NT-proBNP) was available (n = 1256), agreeing to take part in trials remained an independent predictor of survival with log [NT-proBNP].
Conclusion: Those patients with chronic heart failure who express a willingness to take part in a clinical trial, appear to have a better prognosis than those who do not.
Introduction
It is a commonplace requirement in applying for study approval from an Ethics Committee that an investigator has to specify that a patient will not be disadvantaged by choosing not to take part in the study. Indeed, an Ethics Committee would be very likely to turn down a study which declared otherwise as being unduly coercive. However, it is a familiar feature of clinical trials that the prognosis of patients included is, in general, better than might be anticipated from epidemiological data. For example, the 2 years mortality rate in recent chronic heart failure trials has been in the order of 20%, and even in studies of very sick heart failure patients, mortality has only been ~30%. In contrast, data from epidemiological studies suggest that ~40% of people die within a year of diagnosis of heart failure and that survival is worse than for many forms of cancer.
There are a number of possible reasons: patients volunteering to take part in a study might be unrepresentative of the potential treatment population, for example, they may be on average younger, have milder disease and have a positive response to their disease; the study design may exclude patients with more severe disease, complications, or co-morbidities; and the trial itself may confer benefit by offering closer medical and nursing supervision by interested specialists than might otherwise be the case.
We wanted to see if taking part in a clinical trial was associated with a beneficial outcome in patients with chronic heart failure.
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