Department of Medicine, University of California San Francisco, San Francisco, CA, USA.
Nephrol Dial Transplant. 2010 Dec;25(12):3934-9. doi: 10.1093/ndt/gfq299. Epub 2010 Jun 2.
Despite a higher incidence of end-stage renal disease (stage 5), blacks have been shown to have the same or lower prevalence of chronic kidney disease (CKD stages 3 and 4). Current creatinine-based glomerular filtration rate (GFR)-estimating equations may misclassify young, healthy blacks.
Among 3501 young adults (mean age 45), we compared the prevalence of CKD in blacks and whites using the Modification of Diet in Renal Disease (MDRD) and the CKD Epidemiology Collaboration (CKD-EPI) equations. In addition, we used measured creatinine excretion rates to determine the actual excretion ratio for CARDIA (race coefficient 12%) and applied this to the CKD-EPI equation. We also studied the prevalence of CKD risk factors among black and white participants near the CKD threshold cut-off (eGFR CKD-EPI 60-80 mL/min/1.73 m(2)) to estimate the relative likelihood of misclassification in blacks and whites.
Using the MDRD equation, prevalence of CKD stages 4 and 5 was higher for blacks compared with whites (0.6% vs. 0.1%, P-value 0.05). In contrast, prevalence of eGFR <60 mL/min/1.73 m(2) was significantly higher for whites (3.6%) compared with blacks (1.9%), due to higher prevalence of stage 3 among whites. Prevalence of CKD was similar for blacks and whites using CKD-EPI equation (1.2%), but was higher among blacks when using the CARDIA-derived race coefficient (1.6% vs.1.2%, P-value = 0.03). Among persons with eGFR by CKD-EPI of 60-80 mL/min/1.73 m(2), blacks had higher levels of albuminuria, uric acid, systolic blood pressure and higher diabetes prevalence.
CKD classification among young blacks is very sensitive to the race coefficients. Despite whites having higher rates of CKD stage 3, blacks with eGFRs just above the CKD threshold had higher rates of CKD risk factors. Current equations used to define CKD may systematically miss a high-risk group of blacks at a time in the disease course when interventions are crucial.
尽管终末期肾病（第 5 期）的发病率较高，但黑人的慢性肾脏病（CKD 第 3 和第 4 期）患病率却相同或更低。目前基于肌酐的肾小球滤过率（GFR）估算方程可能会错误分类年轻健康的黑人。
在 3501 名年轻成年人（平均年龄 45 岁）中，我们使用肾脏病饮食改良试验（MDRD）和慢性肾脏病流行病学合作（CKD-EPI）方程比较了黑人和白人的 CKD 患病率。此外，我们还使用实测肌酐排泄率来确定 CARDIA（种族系数 12%）的实际排泄比值，并将其应用于 CKD-EPI 方程。我们还研究了接近 CKD 临界值截止点（CKD-EPI 估算的肾小球滤过率[eGFR]60-80 mL/min/1.73 m²）的黑人和白人参与者中 CKD 危险因素的患病率，以估计黑人和白人分类错误的相对可能性。
使用 MDRD 方程，与白人相比，黑人 CKD 第 4 和第 5 期的患病率更高（0.6%比 0.1%，P 值 0.05）。相比之下，白人 eGFR <60 mL/min/1.73 m²的患病率明显高于黑人（3.6%比 1.9%），这是因为白人 CKD 第 3 期的患病率较高。使用 CKD-EPI 方程时，黑人的 CKD 患病率与白人相似（1.2%），但使用 CARDIA 衍生的种族系数时，黑人的 CKD 患病率更高（1.6%比 1.2%，P 值=0.03）。在 CKD-EPI 估算的肾小球滤过率为 60-80 mL/min/1.73 m²的患者中，黑人的白蛋白尿、尿酸、收缩压水平更高，糖尿病患病率也更高。
年轻黑人的 CKD 分类对种族系数非常敏感。尽管白人 CKD 第 3 期的发生率较高，但肾小球滤过率略高于 CKD 阈值的黑人，CKD 危险因素的发生率更高。目前用于定义 CKD 的方程可能会系统性地遗漏疾病过程中一个非常关键的高危黑人亚群。
