Department of Epidemiology, UNC Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC 27599-7435, USA.
Am J Epidemiol. 2011 Apr 1;173(7):768-77. doi: 10.1093/aje/kwq423. Epub 2011 Feb 23.
Hemodialysis patients who live at high altitude use less exogenous erythropoietin but achieve higher hematocrit levels than those living at a lower altitude. The authors hypothesized that the effect of altitude would be strongest in hemodialysis patients with poor anemia treatment response. To explore this hypothesis, they studied anemia-related outcomes in US hemodialysis patients who move to higher altitudes. Using Medicare and US Geological Survey data, in 1992-2004 they identified instances in which a patient moved from a dialysis center at an altitude of <2,000 feet (600 m) to one at a higher elevation. Of these moves, 5,274 were ≥3,000 feet (900 m; the altitude group) and 25,345 were 250-500 feet (75-150 m; the control group). Among patients with poor treatment response at baseline, large increases in hematocrit and decreases in erythropoietin dosing were observed in the altitude relative to the control group. At 6 months, hematocrit had increased more in the altitude group (5.1%, 95% confidence interval (CI): 4.1, 6.2 vs. 3.7%, 95% CI: 3.5, 3.9), and erythropoietin dosing decreased more (4,600 units/week, 95% CI: 500, 8,700 vs. 1,700 units/week, 95% CI: 1,000, 2,400). No effect of altitude was observed in patients with better treatment response at baseline. These results support the hypothesis that altitude-induced hypoxia reduces erythropoietin requirements in hemodialysis patients with treatment-refractory anemia.
居住在高海拔地区的血液透析患者使用的外源性促红细胞生成素较少，但血细胞比容水平高于居住在低海拔地区的患者。作者假设，海拔的影响在贫血治疗反应差的血液透析患者中最为明显。为了探索这一假设，他们研究了移居到高海拔地区的美国血液透析患者的贫血相关结局。利用医疗保险和美国地质调查局的数据，在 1992 年至 2004 年期间，他们确定了患者从海拔<2000 英尺（600 米）的透析中心转移到海拔更高的透析中心的情况。在这些转移中，有 5274 次转移的海拔高度≥3000 英尺（900 米；海拔组），有 25345 次转移的海拔高度为 250-500 英尺（75-150 米；对照组）。在基线治疗反应较差的患者中，与对照组相比，海拔组的血细胞比容显著增加，促红细胞生成素剂量显著减少。在 6 个月时，海拔组的血细胞比容增加更多（5.1%，95%置信区间（CI）：4.1，6.2 比 3.7%，95%CI：3.5，3.9），促红细胞生成素剂量减少更多（4600 单位/周，95%CI：500，8700 比 1700 单位/周，95%CI：1000，2400）。在基线治疗反应较好的患者中，没有观察到海拔的影响。这些结果支持了这样一种假设，即海拔引起的缺氧会降低治疗抵抗性贫血血液透析患者对促红细胞生成素的需求。
