 |
|
Altitude and All-Cause Mortality in Incident Dialysis Patients
Wolfgang C. Winkelmayer, MD, ScD;
Jun Liu, MD, MS;
M. Alan Brookhart, PhD
JAMA. 2009;301(5):508-512.
Context Patients undergoing dialysis at higher altitude receive lower erythropoietin doses, yet achieve higher hemoglobin concentrations. Increased iron availability caused by activation of hypoxia-induced factors at higher altitude may explain this finding. Hypoxia-induced factors are also involved in other pathways that may affect morbidity and mortality.
Objective To study whether mortality differed by altitude in patients initiating dialysis.
Design, Setting, and Participants Retrospective cohort of patients initiating dialysis in the United States between 1995 and 2004. Patients were stratified by the average elevation of their residential zip code. Covariates included age, sex, race, Medicaid coverage, dialysis modality, comorbidities, and reported laboratory measurements. We constructed proportional hazards models of all-cause mortality, stratifying by year, and censoring patients at 5 years from first dialysis, at the end of the database (December 31, 2004), or loss to follow-up. We also compared age- and sex-adjusted standardized mortality rates of US patients receiving dialysis with the general population.
Main Outcome Measure Mortality from any cause.
Results A total of 804 812 patients initiated dialysis and were followed up for a median of 1.78 years. Crude mortality rates per 1000 person-years were 220.1 at an altitude lower than 76 m (<250 ft), 221.2 from 76 through 609 m (250-1999 ft), 214.6 from 610 through 1218 m (2000-3999 ft), 184.9 from 1219 through 1828 m (4000 to 5999 ft), and 177.2 at an altitude higher than 1828 m (>6000 ft). After multivariable adjustment, compared with patients living at an altitude of lower than 76 m, the relative mortality rates were 0.97 (95% confidence interval [CI], 0.96-0.98) for those living from 76 through 609 m; 0.93 (95% CI, 0.91-0.95), from 610 through 1218 m; 0.88 (95% CI, 0.84-0.91), from 1219 through 1828 m, and 0.85 (95% CI, 0.79-0.92) higher than 1828 m. Age- and sex-standardized mortality decreased more with altitude in patients receiving dialysis than in the general population.
Conclusions Altitude was inversely associated with all-cause mortality among US patients receiving dialysis.
Author Affiliations: Division of Pharmacoepidemiology and Pharmacoeconomics (Drs Winkelmayer, Liu, and Brookhart) and Renal Division (Dr Winkelmayer), Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati  Twitter
What's this?
RELATED LETTERS
Association Between Altitude and Mortality in Incident Dialysis Patients
Ji Young Shin and William C. Steinmann
JAMA. 2009;301(23):2442.
EXTRACT
| FULL TEXT
Association Between Altitude and Mortality in Incident Dialysis Patients
Robert Scragg, Ravi Thadhani, and Carlos A. Camargo, Jr
JAMA. 2009;301(23):2442-2443.
EXTRACT
| FULL TEXT
Association Between Altitude and Mortality in Incident Dialysis Patients
Stanley Shaldon
JAMA. 2009;301(23):2443.
EXTRACT
| FULL TEXT
Association Between Altitude and Mortality in Incident Dialysis Patients—Reply
Wolfgang C. Winkelmayer and M. Alan Brookhart
JAMA. 2009;301(23):2443.
EXTRACT
| FULL TEXT
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES
|
Resolved: Targeting a Higher Hemoglobin Is Associated with Greater Risk in Patients with CKD Anemia: Pro
Singh et al.
J. Am. Soc. Nephrol. 2009;20:1436-1443.
ABSTRACT
| FULL TEXT
Association Between Altitude and Mortality in Incident Dialysis Patients
Shin and Steinmann
JAMA 2009;301:2442-2442.
FULL TEXT
Association Between Altitude and Mortality in Incident Dialysis Patients
Shaldon
JAMA 2009;301:2443-2443.
FULL TEXT
Association Between Altitude and Mortality in Incident Dialysis Patients
Scragg et al.
JAMA 2009;301:2442-2443.
FULL TEXT
|
