Estimating kidney function in adults using formulae
Department of Clinical Biochemistry, East Kent Hospitals NHS Trust, Canterbury, Kent, UK. Annals of Clinical Biochemistry
(Impact Factor: 2.34).
10/2005; 42(Pt 5):321-45. DOI: 10.1258/0004563054889936
With increasing emphasis on the earlier detection and management of chronic kidney disease (CKD), estimation of the glomerular filtration rate (GFR) has assumed greater importance. It is accepted that use of serum creatinine concentration alone as a marker of kidney function is inadequate; in particular, it has a poor sensitivity for detecting CKD. International recommendations favour the reporting of creatinine-based estimates of GFR using formulae which also take into account age, gender and other variables that affect the relationship between serum creatinine and GFR: in particular, the four-variable formula derived from the Modification of Diet in Renal Disease study (4-v MDRD) is increasingly being used. We have reviewed the literature supporting the use of this formula compared with the well-established Cockcroft and Gault formula. Overall, evidence supports the use of the 4-v MDRD formula as an improved estimate of GFR in people with moderate/advanced CKD. Neither formula performs well in people with normal and mildly reduced kidney function. However, there remain significant problems with this approach and areas where further research is required. In particular, the widespread adoption of estimated GFR reporting has refocused attention on the limitations of creatinine measurement and highlighted clinical situations in which the formulae are inadequate.
Available from: PubMed Central
- "Undeniably, the large volume of sample is one of the major reasons for patients' refusal of the conventional sampling method. To address this shortcoming of the sampling, spot urine samples showed to be as accurate as timed urine collections for many variables including calculations of variety of indicators of kidney function [9–11]. But this compromise of timed sampling is not applicable for some clinical settings and 24-hour urine collection is still mandatory. "
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ABSTRACT: Background and Objectives. This study proposes a novel urine collection device that can divide each urine collection into 20 parts and store and cool just one part. The aim of the current study is to compare measured biomarkers from the proposed urine collection device to those of conventional 24-hour sampling method. We also hypothesized that the new method would significantly increase patients’ adherence to the timed urine collection. Methods. Two 24-hour urine samples with the conventional method and with the new automated urine collection device that uses just one-twentieth of each void were obtained from 40 healthy volunteers. Urine parameters including volume, creatinine, and protein levels were compared between the two methods and the agreement of two measurements for each subject was reported through Bland-Altman plots. Results. Our results confirmed that for all three variables, there is a positive correlation
between the two measurements and high degree of agreement could be seen in Bland-Altman plots. Moreover, more subjects reported the new method as “more convenient” for 24-hour urine collection. Conclusions. Our results clearly indicate that a fixed proportion of each void may significantly reduce the urine volume in timed collections and this, in turn, may increase subjects’ adherence to this difficult sampling.
- "Estimation of GFR by the CG/BSA and MDRD equations has observed a good correlation (r = 0.85) consistent with the finding by Singh, et al. The observed prevalence of CKD in this study is comparable with the findings of other community-based studies from other developed and developing countries.[33–39] "
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ABSTRACT: The burden of noncommunicable diseases is rising in India. A high prevalence of lifestyle-related diseases in perimenopausal women in the community makes them vulnerable to chronic kidney diseases (CKD). A cross-sectional community-based study was carried out among women >35 years of age in the village of Ballabgarh, Haryana (north India). Eligible women were selected by the probability proportionate to size sampling method. Estimation of glomerular filtration rate (GFR) was carried out by using the age- and body surface area (BSA)-adjusted Cockcroft-Gault (CG) and modification of diet in renal disease (MDRD) equations. Association of risk factors such as obesity, hyperlipidemia, hypertension, and diabetes mellitus with CKD was also assessed using multivariate logistic regression analysis. A total of 455 women were studied. The prevalence of low GFR (<60 mL/min/1.73 m(2)) by the CG/BSA equations and MDRD equation was found to be 18.2% (95% confidence interval 14.6, 21.8) and 5.9% (95% confidence interval 3.7, 8.1), respectively. Obesity (odds ratio 15.5) (P = 0.002), hyperlipidemia (odds ratio: 2.5) (P = 0.017), and age (P < 0.001) were significantly associated with reduced GFR on multivariate logistic regression analysis. This study observed a high prevalence of CKD and its risk factors among perimenopausal women in a rural community in north India. The study highlights the need of a multipronged, community-based intervention strategy that includes a high-risk screening approach and awareness generation about CKD and its risk factors in the community.
Available from: Allison J Craig
- "The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) (National Kidney Foundation, 2002) recommends the use of the eGFR along with markers of kidney damage for staging chronic kidney disease (CKD). These estimation equations are now commonly used in clinical practice for various clinical applications (Lamb et al, 2005; Thomsen, 2007; Craig et al, 2011; National Kidney Disease Education Program, 2012). "
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Glomerular filtration rate (GFR) is used in the calculation of carboplatin dose. Glomerular filtration rate is measured using a radioisotope method (radionuclide GFR (rGFR)), however, estimation equations are available (estimated GFR (eGFR)). Our aim was to assess the accuracy of three eGFR equations and the subsequent carboplatin dose in an oncology population.
Patients and methods:
Patients referred for an rGFR over a 3-year period were selected; eGFR was calculated using the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Cockcroft-Gault (CG) equations. Carboplatin doses were calculated for those patients who had received carboplatin chemotherapy. Bias, precision and accuracy were examined.
Two hundred and eighty-eight studies met the inclusion/exclusion criteria. Paired t-tests showed significant differences for all three equations between rGFR and eGFR with biases of 12.3 (MDRD), 13.6 (CKD-EPI) and 7.7 ml min−1 per 1.73 m2 (CG). An overestimation in carboplatin dose was seen in 81%, 87% and 66% of studies using the MDRD, CKD-EPI and CG equations, respectively.
The MDRD and CKD-EPI equations performed poorly compared with the reference standard rGFR; the CG equation showed smaller bias and higher accuracy in our oncology population. On the basis of our results we recommend that the rGFR should be used for accurate carboplatin chemotherapy dosing and where unavailable the use of the CG equation is preferred.
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