By Peter Laird, MD
The FHN nocturnal hemodialysis study suffered severe recruitment difficulties leading to significantly lower total number of expected patients for this study. Today, despite the many flaws of this study, some are calling into question whether we should offer any patients home nocturnal dialysis any longer on the basis of this so called "negative" study.
Frequent nocturnal hemodialysis has emerged as a promising option for patients, with some studies demonstrating that it improves clinical outcomes. However, the negative results of a recent randomized trial have cast some doubt on whether nocturnal home hemodialysis has any advantages over conventional hemodialysis.
During my internal medicine training, learning how to evaluate medical studies became an important part of my learning experience. We were taught to apply the McMaster critical review process to all of the studies we evaluated in our monthly journal clubs presentations. This incorporated not only methods and analytical tools utilized in the study but also weaknesses in methodology and any bias that may have been inherent to the research. Understanding that the conclusions drawn by researchers are only as good as the evidence it is based upon is at the heart of incorporating any research article into daily medical practice.
One of the most important aspects of the McMaster critical review process is whether the conclusions are trustworthy and will apply to your practice as a physician. The nocturnal arm of the FHN is one study that is fraught with errors that render any conclusions null and void due to the serious flaws in methodology and execution of the planned study. To draw any conclusions when a study has such serious errors in methodology is simply ignoring the one conclusion you must assess with any medical study: does this study reflect my own patient population and how trustworthy are the results.
Despite nearly a decade of planning and executing this study, to state it represents a negative outcome for nocturnal dialysis misses the point that it is simply a null and void study that failed to answer any questions presented. It is not a study that should in any manner slow enthusiasm for nocturnal hemodialysis. Unfortunately, it is one more example of how a randomized and controlled trial is not always the final answer to a clinical question especially one hampered by recruitment issues where patients simply did not consider the treatment options equal. The most serious failure of the FHN nocturnal study is the most important, it is not trustworthy or generalizable due to over selection, nor even repeatable. These are all failures that render any results essentially irrelevant to answering the questions it was designed to answer. In a word, the FHN nocturnal study is simply a failure that should not be repeated or utilized for any clinical decisions.