Higher serum creatinine concentrations in black patients with chronic kidney disease: beyond nutritional status and body composition.
OBJECTIVE
Serum creatinine concentrations tend to be higher in black than white individuals and people of other races or ethnicities. These differences have been assumed to be largely related to race-related differences in body composition, especially muscle mass.


METHODS
In a diverse population of hemodialysis patients, we compared mean serum creatinine concentrations in black versus nonblack patients, adjusting for case mix (age, gender, diabetes, and dialysis vintage), body size (height, weight), laboratory parameters of nutritional status (albumin, predialysis blood urea nitrogen, transferrin, phosphorus, glucose), dialysis dosage (urea reduction ratio), and parameters of bioelectrical impedance (resistance and reactance), proxies for body composition.


RESULTS
Adjusted mean serum creatinine concentrations were significantly higher in black versus nonblack patients (11.7 versus 10.0 mg/dl; P < 0.0001). Black patients were roughly four-fold more likely to have a serum creatinine concentration >10 mg/dl and six-fold more likely to have a serum creatinine concentration >15 mg/dl. Higher serum creatinine concentrations were associated with a lower relative risk for death (0.93; 95% confidence interval 0.88 to 0.98 per mg/dl); the association was slightly more pronounced among nonblack patients.


CONCLUSIONS
Serum creatinine concentrations are significantly higher in black compared with nonblack hemodialysis patients; these differences are not readily explained by differences in nutritional status or body composition.
Hsu
Joy
J
Stanford University School of Medicine, Grant Building, S-161, Stanford, CA 94305-5114, USA.
Johansen
Kirsten L
KL
Hsu
Chi-Yuan
CY
Kaysen
George A
GA
Chertow
Glenn M
GM
D000328:Adult; D001741:Black or African American; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D001806:Blood Urea Nitrogen; D001823:Body Composition; D001827:Body Height; D001835:Body Weight; D002908:Chronic Disease; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood*; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000097:blood* / Q000208:ethnology* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D010758:Phosphorus / Q000097:blood; D006435:Renal Dialysis; D012709:Serum Albumin / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism; D014481:United States; D015854:Up-Regulation
D001786:Blood Glucose; D012709:Serum Albumin; D014168:Transferrin; D010758:Phosphorus; D003404:Creatinine