How to present treatment effects of implantable defibrillators? Statistics, baseline risk, and meaningful benefit

D. A. M. J. Theuns
2013 Europace  
Patients with left ventricular dysfunction are prone to sudden cardiac death, presumably from ventricular tachyarrhythmias. Randomized controlled trials (RCTs) demonstrated that prophylactic implantable cardioverter-defibrillators (ICDs) improve survival among selected patients with left ventricular dysfunction considered at high risk of sudden cardiac death. Based on these clinical trial data, the indications for ICD therapy rapidly expanded from restricted therapy of 'last resort' (secondary
more » ... revention) to a broad-reaching pre-emptive therapy (primary prevention). However, the survival benefit of prophylactic ICD therapy is not uniform across the population with implants. For evidence to be of value, healthcare professionals, patients, and policy makers are faced with the challenge to interpret and apply the data of RCTs in daily practice. Simplified, they need to understand whether one treatment is better than another or better than no treatment at all. Clinicians have the task to communicate risk of a particular treatment to their patients. So, do we understand the concept of risk of a particular treatment, and how do we communicate this to our patients? In recent years, the amount of medical literature has increased rapidly, and with the Internet era information on medical research has become more easily accessible. The problem is how to interpret the results of several studies and decide whether it justifies changing the current treatment. The poor presentation of medical statistics of risk associated with a particular treatment can lead to poor decision-making. There are several statistical formats to present risk and risk reductions. Formats for presenting risk include frequency, percentage, and probability. Formats for presenting risk reduction include relative risk reduction (RRR), absolute risk reduction (ARR), and numbers needed to treat (NTT).
doi:10.1093/europace/eut064 pmid:23515339 fatcat:nfcvma56t5gzvldagh4pyqzxr4