By Peter Laird, MD
The NEJM recently published a widely acclaimed study on the elevated death rates of 32,065 hemodialysis patients on Monday and Tuesday after the long "killer weekend." This is considered one of the most important medical studies in the field of nephrology in 2011. The Renal Fellow Network does an annual survey on the most important clinical developments each year and then publishes the results in a top ten posting. This year, the NEJM elevated mortality with the long interdialytic interval article was rated as the third most important study in 2011. (here)
BACKGROUND: Patients with end-stage renal disease requiring dialysis have limited tolerance of metabolic and volume-related deviations from normal ranges; in addition, the prevalence of cardiovascular disease is high among such patients. Given these problems, we hypothesized that a long interdialytic interval is associated with adverse events in patients receiving hemodialysis.
CONCLUSIONS: The long (2-day) interdialytic interval is a time of heightened risk among patients receiving hemodialysis. (Funded by the National Institutes of Health.)
However, these were not new and groundbreaking results. The issue of increased deaths with the long interdialytic interval is a well known phenomenon that has been ignored by nephrology for more than a decade. A.J. Bleyer et al, studied the records of 375,482 dialysis patient deaths in the USRDS from 1977 to 1997, a twenty year study period. This study showed direct evidence of an increased risk of death from hemodialyis after the long interdialytic interval which was not found in PD patients. PD patients deaths are evenly distributed among each day of the week. Likewise, non cardiac deaths in hemodialysis patients are not elevated on Monday or Tuesday.
The results from the entire USRDS database indicated a nonrandom distribution of cardiac deaths for HD patients. Figures 1 and 2 demonstrate that although cardiac and noncardiac deaths for PD patients are rather evenly distributed throughout the week, cardiac deaths in HD patients occur most frequently on Monday, with the next most common day of death being Tuesday. In addition, noncardiac deaths for HD patients are evenly distributed throughout the week.
Data from the CMAS were then used to identify the most likely dialysis schedule. MWF HD patients were much more likely to die a cardiac death on Monday than other days of the week. Wednesday and Friday—the other dialysis days—were the next most common days of cardiac death. Deaths from noncardiac causes were evenly distributed. Patients on a TTS dialysis schedule were more likely to die from a cardiac cause on Tuesday than other days, although these changes were not as prominent.
BACKGROUND: For patients with end-stage renal disease and their providers, dialysis unit-based cardiac arrest is the most feared complication of hemodialysis. However, relatively little is known regarding its frequency or epidemiology, or whether a fraction of these events could be prevented.
METHODS: To explore clinical correlates of dialysis unit-based cardiac arrest, 400 reported arrests over a nine-month period from October 1998 through June 1999 were reviewed in detail. Clinical characteristics of patients who suffered cardiac arrest were compared with a nationally representative cohort of> 77,000 hemodialysis patients dialyzed at Fresenius Medical Care North America-affiliated facilities.
In my opinion, the most astounding revelation of the NEJM long interdialytic article of 2011 is that there has not been any change in therapy since two much larger studies were published over a decade prior to its publication showing exactly the same results. Mortality among American dialysis patients has flatlined for over twenty years as more and more patients flatline more often on Monday and Tuesday from preventable cardiac deaths. It has puzzled me greatly why this NEJM article made such headline news around the world and fostered surveys declaring this "news" the third most important clinical study of 2011 when in many ways, it was inferior to the prior studies in terms of patient numbers and years of study.
Perhaps we will never know the impetus behind this study and the inordinate attention it received, but we do know that in the year of the bundle going into effect, this study has led many to recommend PD more often instead of looking at alternative HD modalities such as every other day dialysis and daily dialysis. The cost differential for PD vs daily HD points to PD as the most "cost effective" therapies if only considering clinic expenses alone. However, if you consider survival and total patient expenditures including hospitalization and pharmaceuticals, daily HD is the most cost effective and best survival strategy for dialysis patients with PD having equal survival to in-center conventional hemodialysis. (here)
Dr Kjellstrand calculated the number of lives in the last ten years from 2001 to 2011 that could have been saved from what we knew then on the long dialysis weekend excessive deaths. During the time that the FHN study was conceived, planned, implemented and reported, over 10,400 lives a year could have been saved instead of waiting ten years for the publication of the FHN and the long interdialytic weekend mortality studies, both in the NEJM. Sadly, despite all of these studies on the long killer weekend, the best that the academic nephrologists can recommend with confidence to America is that we need to study this issue further before making a commitment to more frequent hemodialysis schedules. How many more years will we see over 10,000 patients needlessly lose their lives year after year after year. This is now a ten year debate that has yet to see any action to eliminate to date. When will we end the killer weekend?
Slides courtesy of Dr. Carl Kjellstrand.