In Reply: In response to Drs Shin and Steinmann, we recognized the possibility that the association between altitude and mortality may be confounded by race. Unfortunately, mortality rate data available from the Centers for Disease Control and Prevention are not provided for all 4 races of interest. Thus, the comparison between the general and the ESRD populations was standardized only for age and sex. However, it is notable that in the general population black individuals experience greater mortality than white individuals, but in the ESRD population the opposite is true.1 Given that relatively few black individuals live at high altitude, the difference between the age-, sex-, and race-standardized relative mortality rates in the general and ESRD populations could be larger than the difference between the age- and sex-standardized rates.
Winkelmayer WC, Brookhart MA. Association Between Altitude and Mortality in Incident Dialysis Patients—Reply. JAMA. 2009;301(23):2442-2443. doi:10.1001/jama.2009.844