Compared to dialysis patients living near sea level, dialysis patients living at an altitude higher than 4,000 feet have a 12-15 percent lower rate of death, according to a study in the February 4 issue of JAMA, the Journal of the American Medical Association.
A recent study found that patients with end-stage renal (kidney) disease (ESRD) living at higher altitude achieved greater hemoglobin concentrations (a protein in red blood cells that primarily transports oxygen from the lungs to the rest of the body) while receiving lower doses of erythropoietin (a hormone that stimulates the production of red blood cells). Increased iron availability caused by activation of hypoxia-induced (oxygen deficiency) factors at higher altitude may explain this finding, according to background information in the article.
Wolfgang C. Winkelmayer, M.D., Sc.D., of Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues examined whether increased altitude would be associated with a reduced rate of death for patients initiating chronic dialysis. Using a comprehensive dialysis registry, the researchers identified 804,812 patients with ESRD who initiated dialysis between 1995 and 2004 and who met the study entry requirements. Most patients resided below an altitude of 250 ft. (40.5 percent) or between 250-1,999 ft. (54.4 percent). Only 1.9 percent of incident dialysis patients lived between 4,000 and 5,999 ft. and 0.4 percent higher than 6,000 ft. Patients were stratified by the average elevation of their residential zip code.
Compared with patients living at lower altitudes (less than 250 ft.), the rate of death was reduced for patients living from 250-1,999 ft. by 3 percent; from 2,000 through 3,999 ft. by 7 percent; from 4,000 to 5,999 ft. by 12 percent; and higher than 6,000 ft. by 15 percent.