title: Impact of activated vitamin D and race on survival among hemodialysis patients.
abstract: Contrary to most examples of disparities in health outcomes, black patients have improved survival compared with white patients after initiating hemodialysis. Understanding potential explanations for this observation may have important clinical implications for minorities in general. This study tested the hypothesis that greater use of activated vitamin D therapy accounts for the survival advantage observed in black and Hispanic patients on hemodialysis. In a prospective cohort of non-Hispanic white (n = 5110), Hispanic white (n = 979), and black (n = 3214) incident hemodialysis patients, higher parathyroid hormone levels at baseline were the primary determinant of prescribing activated vitamin D therapy. Median parathyroid hormone was highest among black patients, who were most likely to receive activated vitamin D and at the highest dosage. One-year mortality was lower in black and Hispanic patients compared with white patients (16 and 16 versus 23%; P < 0.01), but there was significant interaction between race and ethnicity, activated vitamin D therapy, and survival. In multivariable analyses of patients treated with activated vitamin D, black patients had 16% lower mortality compared with white patients, but the difference was lost when adjusted for vitamin D dosage. In contrast, untreated black patients had 35% higher mortality compared with untreated white patients, an association that persisted in several sensitivity analyses. In conclusion, therapy with activated vitamin D may be one potential explanation for the racial differences in survival among hemodialysis patients. Further studies should determine whether treatment differences based on biologic differences contribute to disparities in other conditions.
authors.affiliation: Renal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Myles
authors.initials: M
authors.lastname: Wolf
authors.forename: Joseph
authors.initials: J
authors.lastname: Betancourt
authors.forename: Yuchiao
authors.initials: Y
authors.lastname: Chang
authors.forename: Anand
authors.initials: A
authors.lastname: Shah
authors.forename: Ming
authors.initials: M
authors.lastname: Teng
authors.forename: Hector
authors.initials: H
authors.lastname: Tamez
authors.forename: Orlando
authors.initials: O
authors.lastname: Gutierrez
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
authors.forename: Michal
authors.initials: M
authors.lastname: Melamed
authors.forename: Keith
authors.initials: K
authors.lastname: Norris
authors.forename: Meir J
authors.initials: MJ
authors.lastname: Stampfer
authors.forename: Neil R
authors.initials: NR
authors.lastname: Powe
authors.forename: Ravi
authors.initials: R
authors.lastname: Thadhani
mesh_terms: D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000188:drug therapy; D007676:Kidney Failure, Chronic / Q000208:ethnology / Q000401:mortality / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis; D014481:United States / Q000453:epidemiology; D014807:Vitamin D / Q000627:therapeutic use*; D014815:Vitamins / Q000627:therapeutic use*; D044465:White People
chemical_list: D014815:Vitamins; D014807:Vitamin D