Department of Radiology, University of Washington, Seattle, WA, USA.
Center for Kidney Disease, Second Affiliated Hospital of Nanjing Medical University, Nanjing, China.
J Clin Hypertens (Greenwich). 2019 Sep;21(9):1317-1324. doi: 10.1111/jch.13658. Epub 2019 Aug 30.
Impaired orthostatic blood pressure (BP) stabilization is prevalent in patients with chronic kidney disease (CKD) and is associated with adverse outcomes. We aimed to test the hypothesis that reduced hemoglobin is an important contributor to orthostatic intolerance in CKD in the present study. This study included 262 patients with non-dialysis-dependent CKD. Seated and standing BP was measured, and orthostatic BP reduction was calculated for both systolic BP (∆ SBP) and diastolic BP (∆ DBP). The association between orthostatic BP reduction and hemoglobin was determined by multiple linear regression models. We also performed mediation analysis to test to what extent the effect of renal dysfunction on impaired orthostatic BP stabilization can be explained by reduced hemoglobin. The mean age of the patients was 57.7 (±14.5) years, and 61.5% were male. Both ∆ SBP and ∆ DBP correlated negatively with estimated glomerular filtration rate (eGFR). With adjustment for age and sex, hemoglobin level was negatively associated with ∆ SBP (β = -1.4, SE = 0.4, P < .001) and ∆ DBP (β = -0.6, SE = 0.2, P = .009). The associations remained significant with further adjustment for additional covariates. When eGFR was introduced as a covariate, it did not eliminate the significance (both P < .05). The associations remained essentially unchanged in a sensitivity analysis excluding those with concurrent erythropoietin use. Mediation analysis demonstrated that reduced hemoglobin accounted for 35.4% (P = .004) of the effect of eGFR on ∆ SBP and 47.7% (P = .032) on ∆ DBP. Our study suggests that reduced hemoglobin is a potentially important contributor to the development of orthostatic hypotension in CKD.
体位性血压（BP）稳定受损在慢性肾脏病（CKD）患者中很常见，并且与不良预后相关。本研究旨在检验一个假设，即血红蛋白减少是 CKD 患者体位不耐受的一个重要因素。本研究纳入了 262 名非透析依赖的 CKD 患者。测量了患者的坐姿和站立位血压，并计算了收缩压（∆ SBP）和舒张压（∆ DBP）的体位性血压降低值。采用多元线性回归模型确定体位性血压降低与血红蛋白之间的关系。我们还进行了中介分析，以测试肾功能障碍对体位性血压稳定受损的影响有多少可以通过血红蛋白减少来解释。患者的平均年龄为 57.7（±14.5）岁，61.5%为男性。∆ SBP 和 ∆ DBP 均与估算肾小球滤过率（eGFR）呈负相关。在校正年龄和性别后，血红蛋白水平与 ∆ SBP（β=-1.4，SE=0.4，P<.001）和 ∆ DBP（β=-0.6，SE=0.2，P=0.009）呈负相关。进一步调整其他协变量后，这些相关性仍然具有统计学意义。当将 eGFR 作为协变量引入时，其显著性并未消除（两者均 P<.05）。在排除同时使用促红细胞生成素的患者后进行敏感性分析，其相关性基本保持不变。中介分析表明，血红蛋白减少解释了 eGFR 对 ∆ SBP 的 35.4%（P=.004）和对 ∆ DBP 的 47.7%（P=.032）的影响。本研究表明，血红蛋白减少可能是 CKD 患者发生体位性低血压的一个重要因素。
