Seasonal variations in mortality and clinical indicators in international hemodialysis populations from the MONDO registry.
BACKGROUND
Seasonal mortality differences have been reported in US hemodialysis (HD) patients. Here we examine the effect of seasons on mortality, clinical and laboratory parameters on a global scale.


METHODS
Databases from the international Monitoring Dialysis Outcomes (MONDO) consortium were queried to identify patients who received in-center HD for at least 1 year. Clinics were stratified by hemisphere and climate zone (tropical or temperate). We recorded mortality and computed averages of pre-dialysis systolic blood pressure (pre-SBP), interdialytic weight gain (IDWG), serum albumin, and log C-reactive protein (CRP). We explored seasonal effects using cosinor analysis and adjusted linear mixed models globally, and after stratification.


RESULTS
Data from 87,399 patients were included (northern temperate: 63,671; northern tropical: 7,159; southern temperate: 13,917; southern tropical: 2,652 patients). Globally, mortality was highest in winter. Following stratification, mortality was significantly lower in spring and summer compared to winter in temperate, but not in tropical zones. Globally, pre-SBP and IDWG were lower in summer and spring as compared to winter, although less pronounced in tropical zones. Except for southern temperate zone, serum albumin levels were higher in winter. CRP levels were highest in winter.


CONCLUSIONS
Significant global seasonal variations in mortality, pre-SBP, IDWG, albumin and CRP were observed. Seasonal variations in mortality were most pronounced in temperate climate zones.
Fresenius Latin America, Buenos Aires, Argentina. Adrian.Guinsburg@fmc-ag.com.
Adrian M
AM
Guinsburg
Fresenius Medical Care, Waltham, MA, USA. Len.Usvyat@fmc-na.com.|Renal Research Institute, New York, NY, USA. Len.Usvyat@fmc-na.com.
Len A
LA
Usvyat
Fresenius Asia Pacific Limited, Hong Kong, Hong Kong. Michael.Etter@fmc-asia.com.
Michael
M
Etter
Fresenius Asia Pacific Limited, Hong Kong, Hong Kong. Xiaoqi.Xu@fmc-asia.com.
Xiaoqi
X
Xu
Renal Research Institute, New York, NY, USA. Stephan.Thijssen@RRINY.COM.
Stephan
S
Thijssen
Fresenius Medical Care, Bad Homburg, Germany. Daniele.Marcelli@fmc-ag.de.
Daniele
D
Marcelli
Fresenius Medical Care, Bad Homburg, Germany. Bernard.Canaud@fmc-ag.com.
Bernard
B
Canaud
Fresenius Latin America, Buenos Aires, Argentina. Cristina.Marelli@fmc-ag.com.
Cristina
C
Marelli
Kuratorium für Dialyse und Nierentransplantation e.V., Neu-Isenburg, Germany. claudiabarth@aol.com.
Claudia
C
Barth
University of California - Santa Barbara, Santa Barbara, CA, United States. yuedong@pstat.ucsb.edu.
Yuedong
Y
Wang
Fresenius Medical Care, Bad Homburg, Germany. paola.carioni@fmc-ag.com.
Paola
P
Carioni
Maastricht University Medical Center, Maastricht, Netherlands. f.vander.sande@mumc.nl.
Frank M
FM
van der Sande
Renal Research Institute, New York, NY, USA. Peter.Kotanko@RRINY.COM.|The Mount Sinai Hospital, New York, NY, USA. Peter.Kotanko@RRINY.COM.
Peter
P
Kotanko
Maastricht University Medical Center, Maastricht, Netherlands. jeroen.kooman@mumc.nl.|Department of Internal Medicine, Division of Nephrology, University Hospital Maastricht, PO Box 5800, 6202, AZ, Maastricht, The Netherlands. jeroen.kooman@mumc.nl.
Jeroen P
JP
Kooman
D000328:Adult; D000368:Aged; D001208:Asia / Q000453:epidemiology; D001794:Blood Pressure; D002097:C-Reactive Protein / Q000378:metabolism; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009656:North America / Q000453:epidemiology; D044349:Oceania / Q000453:epidemiology; D012042:Registries; D006435:Renal Dialysis / Q000401:mortality*; D012621:Seasons; D012709:Serum Albumin / Q000378:metabolism; D013020:South America / Q000453:epidemiology; D014329:Tropical Climate; D015430:Weight Gain
D012709:Serum Albumin; D002097:C-Reactive Protein