DSa Janice, Shetty Sukanya, Bhandary Roopa Rani, Rao Ashalatha V
Postgraduate Student, Department of Biochemistry, K.S Hegde Medical Academy, Mangalore, Karnataka, India.
Professor and Head, Department of Biochemistry, K.S Hegde Medical Academy, Mangalore, Karnataka, India.
J Clin Diagn Res. 2017 Apr;11(4):BC09-BC12. doi: 10.7860/JCDR/2017/26655.9655. Epub 2017 Apr 1.
Chronic Kidney Disease (CKD) is an emerging health problem due to the increasing prevalence of conditions like diabetes mellitus and hypertension. Most patients are diagnosed during the later stages of CKD when the clinical symptoms become apparent. There is a need for early diagnosis to prevent disease progression and associated morbidities. Serum Creatinine (SCr) is commonly used among clinicians to determine renal function. However, SCr is affected by several factors and cannot be entirely relied upon. In pursuit of an alternative indicator of renal function, several biomarkers have been discovered and their utility in prompt diagnosis has been evaluated. Among such biomarkers, serum cystatin C (SCysC) has been extensively studied.
To determine and compare the levels of SCr and SCysC in CKD subjects across various severity groups based on estimated Glomerular Filtration Rate (eGFR).
The study comprised of 120 CKD subjects. SCr was estimated by modified Jaffe's method and SCysC was estimated by particle enhanced immunoturbidimetric method. Estimated GFR (eGFR) was determined using Chronic Kidney Disease Epidemiology collaboration (CKD EPI) 2009 creatinine based formula. Based on eGFR, CKD subjects were further categorized into four groups. Statistical analysis was done using SPSS. Data were represented as median and interquartile range. Kruskal Wallis test was used for comparison between more than two groups. Correlation was done using Pearson's test. Statistical significance was considered as p <0.05.
Both SCr and SCysC levels increased significantly across CKD groups (p<0.001). In CKD subjects with eGFR ≥ 60 ml/min/1.732 m, the median value of SCr (1.01 mg/dl) was well within the normal range while median value of SCysC (1.34 mg/l) was found to be more than the upper reference limit. A positive correlation was present between SCysC and SCr (r=0.875, p<0.001). Both SCysC (r=-0.736) and SCr (r=-0.719) had a negative correlation with eGFR (p<0.001).
SCysC is useful in detecting individuals with CKD having mild decrease in GFR compared to SCr. Both SCr and SCysC levels increase with decrease in eGFR. SCysC may be used to screen patients with poorly controlled diabetes mellitus or hypertension when SCr level is inconclusive.
由于糖尿病和高血压等疾病的患病率不断上升，慢性肾脏病（CKD）已成为一个日益严重的健康问题。大多数患者在CKD后期临床症状明显时才被诊断出来。因此，需要进行早期诊断以预防疾病进展及相关并发症。血清肌酐（SCr）是临床医生常用的评估肾功能的指标。然而，SCr受多种因素影响，不能完全依赖。为了寻找肾功能的替代指标，人们发现了几种生物标志物，并评估了它们在早期诊断中的作用。其中，血清胱抑素C（SCysC）得到了广泛研究。
根据估计的肾小球滤过率（eGFR），测定并比较不同严重程度组的CKD患者的SCr和SCysC水平。
本研究纳入了120例CKD患者。采用改良Jaffe法测定SCr，采用颗粒增强免疫比浊法测定SCysC。使用慢性肾脏病流行病学协作组（CKD EPI）2009年基于肌酐的公式计算估计肾小球滤过率（eGFR）。根据eGFR，将CKD患者进一步分为四组。使用SPSS进行统计分析。数据以中位数和四分位数间距表示。采用Kruskal Wallis检验比较两组以上的数据。采用Pearson检验进行相关性分析。统计学显著性以p<0.05为标准。
CKD各分组中SCr和SCysC水平均显著升高（p<0.001）。在eGFR≥60 ml/min/1.732 m²的CKD患者中，SCr的中位数（1.01 mg/dl）在正常范围内，而SCysC的中位数（1.34 mg/l）高于参考上限。SCysC与SCr呈正相关（r=0.875，p<0.001）。SCysC（r=-0.736）和SCr（r=-0.719）均与eGFR呈负相关（p<0.001）。
与SCr相比，SCysC有助于检测GFR轻度下降的CKD患者。SCr和SCysC水平均随eGFR降低而升高。当SCr水平不确定时，SCysC可用于筛查糖尿病或高血压控制不佳的患者。
