title: Serum Creatinine Modifies Associations between Body Mass Index and Mortality and Morbidity in Prevalent Hemodialysis Patients.
abstract: BACKGROUND
  High body mass index (BMI) is paradoxically associated with better outcomes in hemodialysis (HD) patients. This study aimed to examine whether serum creatinine (Cr), a marker of muscle mass, could modify the association between BMI, and mortality and morbidity in prevalent HD patients.
  
  
  METHODS
  A retrospective study was conducted using a nationwide database from the registry of the Japanese Society for Dialysis Therapy. A total of 119,099 patients were selected (age: 65±12 years; median time on HD: 5.6 years; male: 62%), and we examined the association of basal BMI with mortality and morbidity after a 1-year period. Patients were stratified either by BMI into 4 groups or by serum Cr levels into 3 tertiles. Odds ratio (OR) [95% confidence interval] was calculated by multivariate logistic regression analysis.
  
  
  RESULTS
  Higher BMI did not predict a higher 1-year total mortality. However, when we stratified the patients by serum Cr levels, the risk of cardiac death became significantly higher in obese patients with the lowest Cr levels, in both males (OR 2.82 [1.51-5.27], p<0.01) and females (OR 2.00 [1.03-3.90], p<0.05). The risk of new cerebral infarction was also higher in obese male patients within the lowest Cr tertile. In contrast, there was a significantly lower risk of cardiac, cerebrovascular, and infection-related death in non-obese patients with higher levels of Cr. Higher serum Cr was also related to a lower risk of cardiovascular events and hip fracture in non-obese HD patients.
  
  
  CONCLUSIONS
  The obesity paradox was found to be present in HD patients only when obesity was defined by BMI. Decreased serum Cr levels were found to be positively associated with clinical poor outcomes in all BMI groups. Thus, irrespective of BMI, the evaluation of serum Cr levels is important to predict mortality and morbidity in patients receiving regular HD.
authors.affiliation: Blood Purification Unit, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Sakao
authors.affiliation: Department of Community Health and Preventive Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ojima
authors.affiliation: Internal Medicine I, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Yasuda
authors.affiliation: Committee of Renal Data Registry, Japanese Society for Dialysis Therapy, Tokyo, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Hashimoto
authors.affiliation: Committee of Renal Data Registry, Japanese Society for Dialysis Therapy, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hasegawa
authors.affiliation: Committee of Renal Data Registry, Japanese Society for Dialysis Therapy, Tokyo, Japan.
authors.forename: Kunitoshi
authors.initials: K
authors.lastname: Iseki
authors.affiliation: Committee of Renal Data Registry, Japanese Society for Dialysis Therapy, Tokyo, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Tsubakihara
authors.affiliation: Blood Purification Unit, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kato
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology; D003404:Creatinine / Q000097:blood*; D005260:Female; D006620:Hip Fractures / Q000453:epidemiology; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000401:mortality / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D006435:Renal Dialysis / Q000401:mortality*; D015996:Survival Rate
chemical_list: D015415:Biomarkers; D003404:Creatinine