morning versus evening hemodialysis

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Page 1: Morning versus evening hemodialysis

Nephrology: Shared Decision-Making in the AppropriateInitiation of and Withdrawal From Dialysis. Washington,DC, Renal Physicians Association, 2000, p 31

© 2003 by the National Kidney Foundation, Inc.doi:10.1016/S0272-6386(03)00557-2

MORNING VERSUS EVENING HEMODIALYSIS

To the Editor:We concur with the opinion of Abbott et al,1 who, in

partially replicating our finding of a time-of-day effect ofhemodialysis on survival in elderly patients, noted thatfuture studies should pursue mechanisms underlying suchpotentially important relationships.

One issue not stressed explicitly by Abbott et al,1 how-ever, is that mechanisms underlying morning and eveningimproved survival could be entirely different. The healthiercomposition of their much younger evening dialysis patients(more likely to have received transplants, less likely to bediabetic or have peripheral vascular disease and coronaryheart disease, and more likely to be better nourished [higherserum albumin]) suggests strongly that overall health statusmay have been the defining factor in the improved survivalin this very small, select group from the US Renal DataSystem database. By contrast, the much larger numbers ofpatients on the morning and afternoon shifts and their morecomparable levels of comorbidities suggest to us that chrono-biologic factors could be more salient in differentiating thesurvival between these two shifts. Age-dependent change incircadian rhythms have been well described in many speciesof mammals,2 and elderly humans are known to feel andperform better in the morning hours.3 Such changes mayoperate at the cellular and/or even at the molecular level.4,5

Time-of-day factors may indeed be unrecognized in hemodi-alysis survival and deserve further scrutiny.

Donald L. Bliwise, PhDNancy G. Kutner, PhD

Emory University School of MedicineAtlanta, Georgia

REFERENCES

1. Abbott KC, Reynolds JC, Trespalacios FC, Cruess D,Agodoa LY: Survival by time of day of hemodialysis:Analysis of United States Renal Data System Dialysis Mor-bidity and Mortality Waves III/IV. Am J Kidney Dis 41:796-806, 2003

2. Brock MA: Chronobiology and aging. J Am GeriatrSoc 39:74-91, 1991

3. Monk TH, Reynolds CF III, Buysse DJ, et al: Circa-dian characteristics of healthy 80-year-olds and their relation-ship to objectively recorded sleep. J Gerontol 46:M171-M175, 1991

4. Turek FW, Zee PC (eds): Regulation of Sleep andCircadian Rhythms. New York, NY, Marcel Dekker, 1999

5. Toh KL, Jones CR, He Y, et al: An hPer2 phosphoryla-

tion site mutation in familial advanced sleep phase syn-drome. Science 291:1040-1043, 2001

© 2003 by the National Kidney Foundation, Inc.doi:10.1016/S0272-6386(03)00558-4

In Reply:We fully agree with the excellent comments by Drs

Bliwise and Kutner regarding the possibility that evening-shift hemodialysis patients may not be representative ofpatients on other shifts, and the need for further work in thisarea. The US Renal Data System (USRDS) special studiesrepresent the largest repository of patients likely to ever bereported for associations between time of day of hemodialy-sis and survival. We therefore elected to present all data,even for patients with unknown shifts of hemodialysis, inaccordance with accepted epidemiological principles.1 De-spite the limitations of the dataset, our results suggest thatfuture investigations of the time of day of hemodialysis withpatient survival may also need to assess evening shifts, inaddition to comparison of morning and afternoon shifts.Additional times of day of hemodialysis that could not beassessed by the USRDS may also be of interest. Sincenocturnal hemodialysis usually occurs in a setting of morefrequent or longer hemodialysis,2 it is difficult to identifywhich of those factors are responsible for its reported ben-efits. However, nocturnal hemodialysis has had reportedbenefits on sleep disturbances in hemodialysis patients,3

which is an area of interest to Drs Bliwise and Kutner. Wefully agree that future studies of the effects of time of day ofhemodialysis on outcomes should be randomized and in-clude comparable numbers of patients in each arm.

Kevin C. Abbott, MDJoel C. Reynolds, MD

Walter Reed Army Medical CenterWashington, DC

David F. Cruess, PhDUniformed Services University

of the Health SciencesWashington, DC

Lawrence Y. Agodoa, MDProgram Director, NIDDK, NIH

Bethesda, Maryland

REFERENCES1. Browner WS: Publishing and Presenting Clinical Re-

search, Baltimore, MD, Lippincott Williams & Wilkins,1999

2. Alloatti S, Molino A, Manes M, Bonfant G, Pellu V:Long nocturnal dialysis. Blood Purif 20:525-530, 2002

3. Hanly PJ, Gabor JY, Chan C, Pierratos A: Daytimesleepiness in patients with CRF: Impact of nocturnal hemo-dialysis. Am J Kidney Dis 41:403-410, 2003

© 2003 by the National Kidney Foundation, Inc.doi:10.1016/S0272-6386(03)00559-6

CORRESPONDENCE 213