High Altitudes Linked to Fewer Deaths in Dialysis Patients

Death rate lower in dialysis patients at high altitudes than in general population

TUESDAY, Feb. 3 (HealthDay News) -- Dialysis patients at higher altitudes have lower death rates, even lower than the general population, researchers report in the Feb. 4 issue of the Journal of the American Medical Association.

Wolfgang C. Winkelmayer, M.D., and colleagues from Harvard Medical School in Boston, retrospectively examined the medical records of 804,812 patients initiating dialysis in the United States to determine the relationship between elevation and mortality.

After a median follow-up of 1.78 years, and after adjusting for other factors, the investigators found that mortality fell at higher elevations. Compared with patients living at an altitude less than 76 meters (250 feet), relative mortality rates fell from 0.97 for patients living at 76 to 609 meters (250 to 1,999 feet) to 0.85 for patients living higher than 1,828 meters (6,000 feet), the researchers report. Altitude reduced age- and sex-standardized mortality more in dialysis patients than the general population.

"In conclusion, we found a graded reduction in mortality from any cause in end-stage renal disease patients residing at greater altitude, a finding that was not explained by differences in observed patient characteristics," Winkelmayer and colleagues conclude. "We propose that hypoxia-inducible factors are persistent at high altitude in patients with end-stage renal disease and may confer protective effects."

Authors of the study report financial relationships with the pharmaceutical industry.

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