Higher altitudes may mean longer lifetime for dialysis patients

For patients with end-stage renal disease (ESRD) receiving dialysis, the altitude at which they reside could influence their lifespan. Researchers from Brigham and Women’s Hospital (BWH) found that patients residing at higher altitudes experience up to a 15 percent longer survival rate, compared to those residing at lower attitudes. These findings appear in the Journal of the American Medical Association.

Recent research reported that dialysis patients living at higher altitudes achieved greater response to therapeutic treatment with erythropoietin, a protein that controls red blood cell production. Patients with ESRD are treated with erythropoietin to increase red blood cell production. Researchers believe that hypoxia, or oxygen deficiency in blood, which occurs at higher elevations, may cause the greater effectiveness of erythropoietin as well as other hypoxia-induced factors that could prolong life for dialysis patients.

“The results of our new study imply the possibility of numerous benefits of mild hypoxia for patients undergoing dialysis, in addition to making erythropoietin more effective,” said Wolfgang Winkelmayer, MD, ScD, of the Pharmacoepidemiology and Renal Divisions at BWH and lead study author. “Since patients at higher elevations experience lower rates of death from all causes, it’s possible that hypoxia has a positive effect on various co morbidities associated with ESRD.”

Researchers referenced 804,812 records of patients in the US with ESRD who initiated dialysis between 1995 and 2004, obtained from the US dialysis registry. They examined the differences in mortality rates across different residential altitudes by noting the patients’ zip code and comparing the rates of death from various elevation groups.

Compared with patients living at lower altitudes (less than 250 ft.), the rate of death was reduced for patients living at an elevation of 250 to 1,999 ft by 3 percent; 2,000 to 3,999 ft. by 7 percent; 4,000 to 5,999 ft by 12 percent; and higher than 6,000 ft. by 15 percent.

“Further investigation of the hypoxia-induced factors that may prolong lifespan would help to better understand the exact benefits of residing at a higher altitude,” said Dr. Winkelmayer. “And with more research, additional treatment options could be developed once the details of this relationship are uncovered.”

(Source: Brigham and Women’s Hospital: Journal of the American Medical Association: March 2009)