UNASSIGNED: Primary objectives were to: (1) compare accuracy of glomerular filtration rate equations at baseline and longitudinally in people with stage 3 chronic kidney disease, and test whether accuracy is affected by ethnicity, diabetes, albuminuria and other characteristics; (2) establish the reference change value for significant glomerular filtration rate changes; (3) model disease progression; and (4) explore comparative cost-effectiveness of kidney disease monitoring strategies.
UNASSIGNED: A longitudinal, prospective study was designed to: (1) assess accuracy of glomerular filtration rate equations at baseline (n = 1167) and their ability to detect change over 3 years (n = 875); (2) model disease progression predictors in 278 individuals who received additional measurements; (3) quantify glomerular filtration rate variability components (n = 20); and (4) develop a measurement model analysis to compare different monitoring strategy costs (n = 875).
UNASSIGNED: Primary, secondary and tertiary care.
UNASSIGNED: Adults (≥ 18 years) with stage 3 chronic kidney disease.
UNASSIGNED: Estimated glomerular filtration rate using the Chronic Kidney Disease Epidemiology Collaboration and Modification of Diet in Renal Disease equations.
UNASSIGNED: Measured glomerular filtration rate was the reference against which estimating equations were compared with accuracy being expressed as P30 (percentage of values within 30% of reference) and progression (variously defined) studied as sensitivity/specificity. A regression model of disease progression was developed and differences for risk factors estimated. Biological variation components were measured and the reference change value calculated. Comparative costs of monitoring with different estimating equations modelled over 10 years were calculated.
UNASSIGNED: Accuracy (P30) of all equations was ≥ 89.5%: the combined creatinine-cystatin equation (94.9%) was superior (p < 0.001) to other equations. Within each equation, no differences in P30 were seen across categories of age, gender, diabetes, albuminuria, body mass index, kidney function level and ethnicity. All equations showed poor (< 63%) sensitivity for detecting patients showing kidney function decline crossing clinically significant thresholds (e.g. a 25% decline in function). Consequently, the additional cost of monitoring kidney function annually using a cystatin C-based equation could not be justified (incremental cost per patient over 10 years = £43.32). Modelling data showed association between higher albuminuria and faster decline in measured and creatinine-estimated glomerular filtration rate. Reference change values for measured glomerular filtration rate (%, positive/negative) were 21.5/-17.7, with lower reference change values for estimated glomerular filtration rate.
UNASSIGNED: Recruitment of people from South Asian and African-Caribbean backgrounds was below the study target.
UNASSIGNED: Prospective studies of the value of cystatin C as a risk marker in chronic kidney disease should be undertaken.
UNASSIGNED: Inclusion of cystatin C in glomerular filtration rate-estimating equations marginally improved accuracy but not detection of disease progression. Our data do not support cystatin C use for monitoring of glomerular filtration rate in stage 3 chronic kidney disease.
UNASSIGNED: This trial is registered as ISRCTN42955626.
UNASSIGNED: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 11/103/01) and is published in full in Health Technology Assessment; Vol. 28, No. 35. See the NIHR Funding and Awards website for further award information.
Chronic kidney disease, which affects approximately 14% of the adult population, often has no symptoms but, in some people, may later develop into kidney failure. Kidney disease is most often detected using a blood test called creatinine. Creatinine does not identify everyone with kidney disease, or those most likely to develop more serious kidney disease. An alternative blood test called cystatin C may be more accurate, but it is more expensive than the creatinine test. We compared the accuracy of these two tests in more than 1000 people with moderate kidney disease. Participants were tested over 3 years to see if the tests differed in their ability to detect worsening kidney function. We also wanted to identify risk factors associated with loss of kidney function, and how much the tests normally vary to better understand what results mean. We compared the accuracy and costs of monitoring people with the two markers. Cystatin C was found slightly more accurate than the creatinine test at estimating kidney function when comparing the baseline single measurements (95% accurate compared to 90%), but not at detecting worsening function over time. This means that the additional cost of monitoring people over time with cystatin C to detect kidney disease progression could not be justified. Kidney test results could vary by up to 20% between tests without necessarily implying changes in underlying kidney function – this is the normal level of individual variation. Cystatin C marginally improved accuracy of kidney function testing but not ability to detect worsening kidney function. Cystatin C improves identification of moderate chronic kidney disease, but our results do not support its use for routine monitoring of kidney function in such patients.
■主要目标是:(1)比较3期慢性肾病患者基线和纵向肾小球滤过率方程的准确性,测试准确性是否受种族影响,糖尿病,(2)建立肾小球滤过率显著变化的参考变化值;(3)模型疾病进展;(4)探讨比较肾脏疾病监测策略的成本-效果。
■纵向,前瞻性研究旨在:(1)评估基线时肾小球滤过率方程的准确性(n=1167)及其在3年内检测变化的能力(n=875);(2)对278名接受额外测量的个体进行疾病进展预测模型;(3)量化肾小球滤过率变异性成分(n=20);(4)开发测量模型分析以比较不同的监测策略成本(n=875)。
■主要,二级和三级护理。
■患有3期慢性肾病的成年人(≥18岁)。
■使用慢性肾脏病流行病学合作和修改肾脏病公式中的饮食估计肾小球滤过率。
■测得的肾小球滤过率是比较估算方程的参考,其准确性表示为P30(参考值的30%以内的百分比),进展(不同定义)研究为敏感性/特异性。建立了疾病进展的回归模型,并估计了危险因素的差异。测量生物变异分量并计算参考变化值。计算了10年内采用不同估算方程建模的监测比较成本。
■所有方程的准确性(P30)≥89.5%:肌酐-胱抑素联合方程(94.9%)优于其他方程(p<0.001)。在每个方程中,在不同的年龄类别中没有发现P30的差异,性别,糖尿病,白蛋白尿,身体质量指数,肾功能水平和种族。所有方程显示对于检测显示肾功能下降的患者的差(<63%)的灵敏度,其跨越临床显著阈值(例如功能下降25%)。因此,使用基于胱抑素C的方程每年监测肾功能的额外费用是不合理的(10年以上每位患者的增量费用=£43.32).建模数据显示,较高的白蛋白尿与测量和肌酐估计的肾小球滤过率更快下降之间存在关联。测量的肾小球滤过率参考变化值(%,阳性/阴性)为21.5/-17.7,估计的肾小球滤过率参考变化值较低。
■来自南亚和非洲-加勒比背景的人员的招聘低于研究目标。
■应该对胱抑素C作为慢性肾脏病风险标志物的价值进行前瞻性研究。
■在肾小球滤过率估算方程中纳入胱抑素C略微提高了准确性,但不能检测疾病进展。我们的数据不支持使用胱抑素C监测3期慢性肾脏病的肾小球滤过率。
■本试验注册为ISRCTN42955626。
■该奖项由美国国家卫生与护理研究所(NIHR)卫生技术评估计划(NIHR奖参考:11/103/01)资助,并在《卫生技术评估》中全文发布。28号35.有关更多奖项信息,请参阅NIHR资助和奖励网站。
慢性肾脏病,这影响了大约14%的成年人口,通常没有症状,但是,在一些人中,可能会发展成肾衰竭。肾脏疾病最常使用称为肌酐的血液检查来检测。肌酐并不能确定每个人都有肾脏疾病,或那些最有可能发展为更严重的肾脏疾病。一种叫做胱抑素C的替代血液测试可能更准确,但它比肌酐测试贵。我们在1000多名中度肾脏疾病患者中比较了这两项测试的准确性。参与者进行了3年以上的测试,以查看测试是否在检测肾功能恶化的能力方面存在差异。我们还想确定与肾功能丧失相关的危险因素,以及测试通常会有多少变化,以更好地理解结果的含义。我们将监测人员的准确性和成本与两种标记进行了比较。在比较基线单次测量时,发现胱抑素C在估计肾功能方面比肌酐测试稍微更准确(95%的准确性与90%相比)。但不能检测到随着时间的推移功能恶化。这意味着随着时间的推移用胱抑素C监测患者以检测肾脏疾病进展的额外成本是不合理的。两次测试之间的肾脏测试结果可能会有多达20%的变化,而不一定意味着潜在的肾功能发生变化-这是个体差异的正常水平。胱抑素C略微提高了肾功能测试的准确性,但没有检测肾功能恶化的能力。胱抑素C改善中度慢性肾病的鉴别,但我们的结果不支持将其用于此类患者的肾功能常规监测.