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Revisiting the association between altitude and mortality in dialysis patients
Author(s) -
Shapiro Bryan B.,
Streja Elani,
Rhee Connie M.,
Molnar Miklos Z.,
Kheifets Leeka,
Kovesdy Csaba P.,
Kopple Joel D.,
KalantarZadeh Kamyar
Publication year - 2014
Publication title -
hemodialysis international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.658
H-Index - 47
eISSN - 1542-4758
pISSN - 1492-7535
DOI - 10.1111/hdi.12129
Subject(s) - medicine , dialysis , hemodialysis , altitude (triangle) , intensive care medicine , association (psychology) , emergency medicine , demography , philosophy , epistemology , geometry , mathematics , sociology
It was recently reported that residential altitude is inversely associated with all‐cause mortality among incident dialysis patients; however, no adjustment was made for key case‐mix and laboratory variables. We re‐examined this question in a contemporary patient database with comprehensive clinical and laboratory data. In a contemporary 8‐year cohort of 144,892 maintenance dialysis patients from a large dialysis organization, we examined the relationship between residential altitude and all‐cause mortality. Using data from the US G eological S urvey, the average residential altitudes per approximately 43,000 US zip codes were compiled and linked to the residential zip codes of each patient. Mortality risks for these patients were estimated by C ox proportional hazard ratios. The study population's mean ± standard deviation age was 61 ± 15 years. Forty‐five percent of patients were women, and 57% of patients had diabetes. In fully adjusted analysis, those residing in the highest altitude strata (≥6000 ft) had a lower all‐cause mortality risk in fully adjusted analyses: death hazard ratio: 0.92 (95% confidence interval, 0.86–0.99), as compared with patients in the reference group (<250 ft). Residential altitude is inversely associated in all‐cause mortality risk in maintenance dialysis patients notwithstanding the unknown and unmeasured confounders.