Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA.
Nephrol Dial Transplant. 2010 Aug;25(8):2542-8. doi: 10.1093/ndt/gfq040. Epub 2010 Feb 22.
Anaemia worsens as kidney function declines. Both conditions are associated with increased mortality. Serum cystatin C is purportedly a more sensitive marker of kidney disease and a better predictor of mortality than serum creatinine. However, studies suggest that extrarenal factors also influence cystatin C levels.
We determined whether estimates of glomerular filtration rate [estimated glomerular filtration rate (eGFR)] based on serum cystatin C alone or in combination with serum creatinine were superior to those based on serum creatinine in recognizing impaired kidney function in the setting of anaemia in a sub-sample of the Third National Health and Nutrition Examination Survey of the USA consisting of 6734 participants, 20 years or older.
The prevalence of moderate to severe kidney disease (eGFR 15-59 mL/min/1.73 m(2)) among anaemic persons was 15-16% when based on serum creatinine alone (eGFR(SCR)) or combined with cystatin C (eGFR(SCR) (+) (CYSC)); this estimate increased to nearly 25% when kidney function was estimated by cystatin C (eGFR(CYSC)). The adjusted odds ratios of kidney disease in anaemic versus non-anaemic persons were slightly higher with eGFR(CYSC) than eGFR(SCR) and eGFR(SCR) (+) (CYSC) in younger adults [odds ratio (OR) = 5.22, 95% confidence interval (CI): 2.23, 12.17], women (OR = 5.34, 95% CI: 2.36, 12.06) and those with elevated C-reactive protein (CRP) (OR = 7.36, 95% CI: 1.98-27.36).
Impaired kidney function was common in individuals with anaemia. Among anaemic individuals, the prevalence estimate for kidney disease was notably higher when kidney function was estimated by cystatin C alone compared with the estimations by serum creatinine alone or in combination with serum cystatin C. eGFR(CYSC) may be particularly helpful in identifying kidney disease in the setting of anaemia among younger persons, women and those with elevated CRP. Regardless of which renal biomarker is used, our study suggests that an evaluation for underlying kidney disease should be considered in the standard workup of anaemia.
随着肾功能的下降，贫血会恶化。这两种情况都与死亡率的增加有关。据称，血清胱抑素 C 是一种更敏感的肾脏疾病标志物，并且比血清肌酐更好地预测死亡率。然而，研究表明，肾脏以外的因素也会影响胱抑素 C 水平。
我们在美国第三次国家健康和营养检查调查的一个子样本中，确定了仅基于血清胱抑素 C 或同时基于血清胱抑素 C 和血清肌酐估计的肾小球滤过率[估计肾小球滤过率（eGFR）]是否优于单独基于血清肌酐（eGFR(SCR)）识别贫血患者肾功能受损，该子样本由 6734 名年龄在 20 岁或以上的参与者组成。
在贫血患者中，仅基于血清肌酐（eGFR(SCR))）或同时基于血清肌酐和胱抑素 C（eGFR(SCR) (+) (CYSC)），中度至重度肾脏疾病（eGFR 15-59 mL/min/1.73 m(2))的患病率为 15-16%；当通过胱抑素 C 估计肾功能时，这一估计值增加到近 25%（eGFR(CYSC)）。与 eGFR(SCR)和 eGFR(SCR) (+) (CYSC)相比，年轻成年人（比值比（OR）=5.22，95%置信区间（CI）：2.23，12.17）、女性（OR = 5.34，95% CI：2.36，12.06）和 C 反应蛋白（CRP）升高的患者（OR = 7.36，95% CI：1.98-27.36）中，贫血患者的肾脏疾病的调整比值比更高。
贫血患者中肾功能受损很常见。在贫血患者中，仅通过胱抑素 C 估计肾功能时，与单独通过血清肌酐或同时通过血清肌酐和血清胱抑素 C 估计肾功能时相比，肾脏疾病的患病率估计明显更高。eGFR(CYSC) 可能特别有助于在 CRP 升高的年轻人群、女性和贫血患者中识别肾脏疾病。无论使用哪种肾脏生物标志物，我们的研究都表明，在贫血的标准检查中应考虑进行潜在肾脏疾病的评估。
