Measurement of glomerular filtration rate in renal transplant recipients: A comparison of methods

SUMMARY: While single injection radionuclide and radio‐contrast glomerular filtration rate (GFR) clearance methods are widely used, the relative accuracy of single versus multiple sample techniques continues to be debated. In addition, GFR calculated from the serum creatinine concentration is considered by some to produce results comparable to clearance methods. In this study, 109 patients with stable renal transplant fraction were prospectively evaluated by yearly ⁵¹Cr EDTA clearance as well as by three published formulae used to predict GFR from serum creatinine. Analysis of 362 measurements demonstrated a highly significant correlation between multiple and single point clearance results, as well as the serum creatinine nomograms using least squares regression analysis (P<0.001). the mean GFR was, however, significantly higher using the Cockcroft and Gault formula; 64 ± 18 compared with 47 ± 14 and 50 ± 14 with other serum creatinine formulae, and 46 ± 21–50 ± 17mL/min per 1.73m2 with the three ⁵¹Cr EDTA methods (P<0.01). However, further statistical analysis using more appropriate methods, including an analysis of difference and least product regression analysis did not support any of the methods tested as reliable alternatives to multiple sample ⁵¹Cr EDTA clearance, because both fixed and proportional bias was noted. In a subgroup of 29 patients evaluated yearly over the 7‐year study period, serum creatinine derivations all demonstrated a greater year to year mean fluctuation compared with clearance methods. It is oncluded that while each GFR method has similarities, they are not interchangeable. Until clearance methods and serum creatinine formulae are directly compared with inulin clearance with the use of appropriate statistical evaluation, it is recommended that the Chantler 3 sample ⁵¹Cr EDTA method be the method of choice in clinical laboratories.     

Effect of prostaglandin synthesis inhibition on glomerular filtration rate in renal transplant recipients.

To determine the influence of prostaglandin (PG) synthesis inhibition on the renal function in renal transplant recipients, we carried out a crossover, double-blind, placebo controlled study of 18 ambulatory patients. Glomerular filtration rate (GFR) was measured using 51-Cr EDTA, before and after indomethacin (50 mgr. three times a day for three days), and placebo. Overnight urinary PGE excretion decreased 88.9 +/- SEM 4.81% after indomethacin, but remained unchanged following placebo. GFR decreased 15.3 +/- SEM 3.94% (p = 0.0139) after indomethacin. There was no correlation between PGE urinary excretion and GFR changes. Pre-existing renal functional impairment was not a significant risk factor. Caution should be exercised when using non-steroidal anti-inflammatory drugs in renal transplant patients.     

Long-term cyclosporin A pharmacokinetic profiles in pediatric renal transplant recipients

To study the long-term effect of cyclosporin A (CyA), 94 6-h and 29 12-h pharmacokinetic profiles were evaluated in 32 children at least 1 year after renal transplantation. Children weighing less than 25 kg needed significantly higher doses of CyA than those weighing more than 25 kg(9.8 vs 5.3 mg/kg per day; P<0.001) to achieve similar trough levels (TL). The average dose of CyA required to achieve the target TL declined gradually with time after transplantation. The average area under the curve over 6 h (AUC/6) correlated strongly with the AUC/12 (r=0.967; P<0.001). The AUC/6 of patients with biopsy-proven CyA toxicity was significantly higher than for those without toxicity (Mann-Whitney U-test P<0.05) despite similar TL. We conclude that AUC monitoring for 6 h provides valuable information not only on TL but also on the absorption and elimination characteristics of CyA as well as on the potential for CyA toxicity.     

Dietary supplementation with lish oil modifies renal reserve filtration capacity in postoperative, cyclosporin A-treated renal transplant recipients

Abstract. The effect of a daily supplementation of 6 g fish oil (30% C20:5 omega-3 = EPA and 20% C22:6 omega-3 = DHA) for 1 month on renal function variables was investigated in a placebo-controlled (6 g coconut oil), prospective, randomized, double-blind study in acute postoperative cyclosporin A (CyA)-treated renal transplant recipients. Seventeen patients ingested placebo capsules (EPA-) and 14 patients fish oil (EPA +). Renal function tests were performed using the simultaneous determination of 1251-iothalamate and 1311-hippuran clearances for glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), respectively. Renal reserve filtration capacity was assessed by dopamine infusion, amino acid infusion, and a combination of both stimuli. After 1 month there were no significant differences in rejection episodes, CyA dose, or CyA levels. In contrast to our earlier observations, serum creatinine, creatinine clearance, GFR, and ERPF did not differ between the EPA-and EPA + groups. Filtration fraction (FF) differed significantly, being 0. 21 in the EPA-group versus 0. 26 in the EPA+ group. To exclude the possible influence of a rejection episode, the nonrejecting patients were analyzed separately, creating the subgroups EPA + re-and EPA-re-. These two groups were comparable in age, donor age, and GFR. The EPA + regroup had a significantly lower ERPF (164 ml/min per 1. 73 nr) than the EPA-re-group (262 ml/min per 1. 73 m²). FF was significantly higher in the EPA + re-group (0. 26) than in the EPA-re-group (0. 21). Following dopamine, no significant differences in the percentage increase of GFR and ERPF between both groups were observed, while FF fell to the same extent in both groups. Following amino acids, the fish oil-treated patients had a significantly better response on GFR (EPA + re-15. 3 versus EPA-re-10. 6%; P < 0. 05). The near-normal FF and the better response on amino acid infusion strongly suggest that at 1 month postoperatively, the CyA-and fish oil-treated patients have more balanced renal hemodynamics than the CyA-and coconut oil-treated patients.     

Dietary supplementation with fish oil modifies renal reserve filtration capacity in postoperative,cyclosporin A-treated renal transplant recipients

The effect of a daily supplementation of 6 g fish oil (30% C20:5 omega-3=EPA and 20% C22:6 omega-3=DHA) for 1 month on renal function variables was investigated in a placebo-controlled (6 g coconut oil), prospective, randomized, double-blind study in acute postoperative cyclosporin A (CyA)-treated renal transplant recipients. Seventeen patients ingested placebo capsules (EPA-) and 14 patients fish oil (EPA+). Renal function tests were performed using the simultaneous determination of 125 I-iothalamate and 131 I-hippuran clearances for glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), respectively. Renal reserve filtration capacity was assessed by dopamine infusion, amino acid infusion, and a combination of both stimuli. After 1 month there were no significant differences in rejection episodes, CyA dose, or CyA levels. In contrast to our earlier observations, serum creatinine, creatinine clearance, GFR, and ERPF did not differ between the EPA- and EPA+ groups. Filtration fraction (FF) differed significantly, being 0.21 in the EPA- group versus 0.26 in the EPA+ group. To exclude the possible influence of a rejection episode, the nonrejecting patients were analyzed separately, creating the subgroups EPA+ re- and EPA-re-. These two groups were comparable in age, donor age, and GFR. The EPA+ re-group had a significantly lower ERPF (164 ml/min per 1.73 m²) than the EPA-re- group (262 ml/min per 1.73 m²). FF was significantly higher in the EPA+re-group (0.26) than in the EPA-re- group (0.21). Following dopamine, no significant differences in the percentage increase of GFR and ERPF between both groups were observed, while FF fell to the same extent in both groups. Following amino acids, the fish oil-treated patients had a significantly better response on GFR (EPA+re- 15.3 versus EPA-re- 10.6%; P<0.05). The near-normal FF and the better response on amino acid infusion strongly suggest that at 1 month postoperatively, the CyA- and fish oil-treated patients have more balanced renal hemodynamics than the CyA- and coconut oil-treated patients.     

Limitations of glomerular filtration rate equations in the renal transplant patient

This study aims to compare the performance of endogenous creatinine clearance (CL(cr)) and a number of published mathematical equations to calculate glomerular filtration rate (GFR) in renal transplant patients considering (99m)Tc DTPA isotope scan as the reference method. A total of 152 GFR were performed on 81 renal transplant patients. Accuracy of each method was measured at different percentiles. The bias and precision of all the methods were then compared. A paired t-test was used to compare the performance of each calculation to the respective GFR measured by isotope study performed on the same day. In the total population, all calculated methods correlated significantly with the isotope results. Accuracies within specific ranges of the isotope GFR were limited in all equations (agreement with isotope result /= 50 mL/min and Gates in patients with GFR < 50 mL/min. Salazar (D.E. Salazar and G.B. Corcoran, Am J Med 1988; vol. 84: p. 1053) had the least bias in patients with BMI above 30 kg/m(2) and the Davis equation (G.A. Davis and M.H. Chandler, Am J Health Syst Pharm 1996; vol. 53: p. 1028) in patients with BMI <25 kg/m(2). In all analyses, Nankivell (B.J. Nankivell, S.M. Gruenwald, R.D.M. Allen and J.R. Chapman, Transplantation 1995; vol. 59: p. 1683) overestimated GFR by more than 80% and MDRD 1 and 2 in <10% of the time. The results demonstrate the inherited limitation in the currently available equations to calculate GFR in renal transplant patients.     

The effect of cyclosporin on lower limb blood flow in renal transplant recipients

Abstract. We investigated the effect of electively converting stable renal allograft recipients from cyclosporin A (CyA) to prednisolone and azathioprine on limb blood. We used a non-invasive method designed to measure the hyperaemic blood flow to the lower limb following a standard ischaemic insult. The hyperaemic blood flow was greater during CyA therapy - median 14 ml/100 ml tissue per minute (95% confidence limits 10.5–16.5) - than that after conversion - median 11 ml/100 ml tissue per minute (8.3–13.8; P < 0.01). By increasing peripheral vascular resistance and reducing limb blood flow, CyA may have caused an increase in the degree of ischaemia, so resulting in a greater hyperaemic response.     

The effect of cyclosporin on lower limb blood flow in renal transplant recipients

We investigated the effect of electively converting stable renal allograft recipients from cyclosporin A (CyA) to prednisolone and azathioprine on limb blood. We used a non-invasive method designed to measure the hyperaemic blood flow to the lower limb following a standard ischaemic insult. The hyperaemic blood flow was greater during CyA therapy-median 14 ml/100 ml tissue per minute (95% confidence limits 10.5–16.5)-than that after conversion-median 11 ml/100 ml tissue per minute (8.3–13.8;P<0.01). By increasing peripheral vascular resistance and reducing limb blood flow, CyA may have caused an increase in the degree of ischaemia, so resulting in a greater hyperaemic response.     

Misoprostol in renal transplant recipients: a prospective, randomized, controlled study on the prevention of acute rejection episodes and cyclosporin A nephrotoxicity

The aim of this prospective and randomized study was to determinewhether misoprostol, an analogue of PGE1, could decrease theincidence and the number of rejection episodes and could improvethe renal function over a 12-month follow-up, when given at400 µg/day for 12 months in renal transplant patients.Given the known side-effects and the additive cost of misoprostol,a benefit of the therapy should be a decrease of at least 50%in the incidence of rejection episodes in the treated group.Therefore, 60 consecutive renal transplant patients were randomizedto receive misoprostol or to receive aluminium and magnesiumhydroxide. Patients received steroids, azathioprine, antithymocyteglobulins, and cyclosporin A (CsA). CsA was randomly startedon day 0 or on day 8. At 12 months, no difference in the incidenceof rejection episodes was observed: 63.3% in the 30 patientsof the misoprostol + group versus 70.0% in the misoprostol-group(P=0.558 Mantel-Cox). The renal function, assessed by plasmacreatinine, inulin, and para-aminohippuric acid clearances,was not significantly different between misoprostol + and misoprostol-groups.No episode of CsA nephrotoxicity was observed in any patientof group one or group two. At 12 months, the mean dosage ofCsA was 4.9±0.28 mg/kg/day in the misoprostol+group versus4.52 ± 0.23 mg/kg/day in the misoprostol - group andthe trough level was not significantly different between thetwo groups. The graft survival rate at 12 months was 86.7% inthe Misoprostol+ group and 83.33% in the misoprostol- group.The trial failed to demonstrate a significant beneficial effectof misoprostol on the decrease of acute rejection episodes,on the prevention of CsA nephrotoxicity, or on the improvementof renal function over a 12-month period.     

移植肾肾小球滤过率的检测和评估（附视频）

探讨评估移植肾肾小球滤过率（GFR）的最佳方法,从而早期发现移植肾功能异常并适时干预,对提高肾移植受者的生活质量和长期存活具有重要意义。本文介绍了菊粉清除率、放射性核素法实测GFR,应用外周血清肌酐、血清尿素氮、肌酐清除率等间接评估GFR,以及通过公式估算GFR等各种目前常见的GFR评估方法的原理及其优劣;并根据肾移植受者的特殊情况分析了估算GFR公式的适用性。     

Effects of simvastatin and pravastatin on hyperlipidemia and cyclosporin blood levels in renal transplant recipients.

Thirty-one renal transplant recipients, submitted to treatment with cyclosporin in association with other immunosuppressive agents, were also treated for 9 months with two hydroxymethylglutaryl coenzyme A reductase inhibitors, simvastatin (10 mg/day) or pravastatin (20 mg/day), for concomitant hypercholesterolemia and hypertriglyceridemia. Both drugs significantly decreased total cholesterol and triglyceride serum levels, but they did not modify whole-blood trough concentrations of polyclonal and monoclonal cyclosporin or polyclonal/monoclonal cyclosporin ratio. No alterations of the clinical and laboratory parameters investigated were found. The results of this study show the efficacy and safety of hydroxymethylglutaryl coenzyme A reductase inhibitors in the treatment of hyperlipidemia in kidney transplant patients.     

肾移植术后随访中检测受者血清胱抑素C的临床价值

目的 探讨血清胱抑素C(SCys C)浓度检测能否作为肾移植受者随访中移植肾功能测定的理想指标.方法 选择肾移植术后接受长期随访的受者70例,于随访当日检测受者SCys C和血清肌酐(SCr)水平,同时用99mTc-DTPA肾动态显像测定肾小球滤过率(GFR),比较SCys C和SCr与GFR的相关性,并应用受试者工作特征曲线(ROC曲线)评价两者在诊断移植肾功能轻度损伤(GFR＜1 ml/s)中的效果.结果 随访的肾移植受者中,SCys C和SCr与GFR均呈负相关,相关系数分别为-0.82和-0.66(P＜0.01).SCys C用于诊断移植肾功能轻度损伤的敏感度、特异度和阳性预测值(PPV)均高于SCr.SCys C的ROC曲线下面积高于SCr(分别为0.935和0.877),但两者比较,差异无统计学意义(P＞0.05).结论 在肾移植术后的随访中,受者SCys C与GFR的相关性比SCr更高,可作为评估移植肾功能的较理想指标.     

Cystatin C-based calculation of glomerular filtration rate in kidney transplant recipients

Cystatin C (Cys C) has been shown to be an alternative marker of renal function. However, estimation of the glomerular filtration rate (GFR) based on Cys C has received little attention. Recently, several Cys C-based equations were developed in different patient cohorts. To date, the benefit of a Cys C-based GFR calculation in patients after renal transplantation (RTx) remains to be elucidated. We compared the diagnostic accuracy of three Cys C-based formulae (Larsson, Hoek, Filler which used an immunonephelometric method) with the results of the Modification of Diet in Renal Disease (MDRD) formula. GFR was measured by means of technetium-diethylenetriamine pentaacetic acid ((99m)Tc-DTPA) clearance in 108 consecutive patients after RTx. Correlation coefficients of all calculated GFR estimates with the true GFR were high but did not differ significantly from one another (0.83-0.87). The MDRD and Filler equations overestimated GFR significantly, whereas the Larsson equation significantly underestimated GFR. Bias of the Hoek formula was negligible. Precision of the Hoek (8.9 ml/min/1.73 m(2)) and Larsson equations (9.6 ml/min/1.73 m(2)) were significantly better than MDRD equations (11.4 ml/min/1.73 m(2); P< or =0.035 each). Accuracy within 30% of real GFR was 67.0 and 65.1% for the MDRD and Filler formulae, and 77.1% for the Larsson and Hoek formulae, respectively. Accuracy within 50% of true GFR for the Hoek formula (97.2%) was better than for the MDRD equations (85.3%). Cys C-based formulae may provide a better diagnostic performance than creatinine-based equations in GFR calculation after RTx.     

Cimetidine improves prediction of the glomerular filtration rate by the Cockcroft-Gault formula in renal transplant recipients

BACKGROUND: The glomerular filtration rate (GFR) can be predicted from plasma creatinine, age, gender, and body weight, using the formula of Cockcroft and Gault. Cimetidine improved the accuracy of GFR prediction in renal disease and also in diabetes mellitus type 2, due to inhibition of tubular creatinine secretion. We compared the accuracy and precision of GFR prediction from the Cockcroft-Gault formula without cimetidine (CG), with cimetidine (CGcim) and from the creatinine clearance without cimetidine in renal transplant recipients. METHODS: CG and CGcim were calculated from plasma creatinine before and after 2400 mg of oral cimetidine during the 24 hr preceding the GFR measurement. The endogenous creatinine clearance was measured in 24 outpatients from a 24-hr urine collection (Ccr24) before cimetidine. GFR was measured as the urinary clearance of continuously infused 125I-iothalamate. Creatinine was determined with an automated enzymatic assay in plasma and with an alkaline picrate assay in urine. RESULTS: GFR was 47.8+/-16.8 ml/min/1.73 m2 (mean+/-SD), Ccr24 was 71.8+/-23.1 ml/min/1.73 m2, CG was 62.2+/-15.2 ml/min/1.73 m2, and CGcim was 52.8+/-14.9 ml/min/1.73 m2. Ccr24 overestimated GFR in every patient by an average of 23.8 ml/min/1.73 m2 and CG by an average of 14.3 ml/min/1.73 m2, whereas CGcim overestimated GFR significantly less by an average 4.9 ml/min/1.73 m2 (P<0.001). The precision of CGcim was significantly better than that of Ccr24: the SD of the difference from GFR was 9.0 ml/min/1.73 m2 for CGcim and 14.5 ml/min/1.73 m2 for Ccr24 (P<0.05). CONCLUSION: CGcim is useful for GFR prediction in outpatient renal transplant recipients and has a far better accuracy and precision than Ccr24 and also a better accuracy than CG. We propose a strategy after kidney transplantation of one GFR measurement at baseline and follow-up with CGcim.     

Effect of cyclosporin A on glomerular filtration rate in children with minimal change nephrotic syndrome

Cyclosporin A (CyA) is now commonly used in the management of children with steroid-dependent nephrotic syndrome. In order to assess nephrotoxicity related to CyA therapy, we measured glomerular filtration rate (GFR) on 123 occasions in 24 children with minimal change nephrotic syndrome receiving CyA. GFR was estimated from the plasma clearance of⁵¹chromium-EDTA every 3 months during CyA therapy of up to 27 months duration. There was a significant reduction in GFR after 3 months of CyA therapy [118±33 (SD) to 93±24 ml/min per 1.73 m²] but no further fall thereafter, although the reduction in GFR was sustained for the duration of CyA therapy. This reduction in GFR appeared to be reversible upon cessation of CyA, but careful monitoring of renal function is necessary in such patients to prevent the development of longer term nephrotoxic sequelae.     

Effects of the prostacyclin analogue iloprost on cyclosporin-induced renal hypoperfusion in stable renal transplant recipients

BACKGROUND.: The synthetic prostacyclin analogues have been proposed to protectagainst cyclosporin A (CsA) nephrotoxicity. The present studyinvestigated the effect of infusion of the prostacyclin analogueiloprost on the acute CsA-induced renal hypoperfusion and hypofiltrationin stable renal-transplant recipients. METHODS.: The study included 10 stable renal-transplant recipients withgood graft function (s-creatinine 90–170 umol/1). Renalfunction and the acute renal haemodynamic and tubular responseto an oral CsA-dose (Sandimmun Neoral, 3 mg.kg^–1) wereinvestigated with an infusion of iloprost (1 ng.kg^–1.min^–1)or placebo on 2 separate days. After an overnight fast, seven30-min renal clearance periods were performed, two before infusion,three during infusion, and two recovery periods. An additionalcontrol clearance study without CsA intake or iloprost/placeboinfusion was done in eight of the patients. RESULTS.: CsA ingestion decreased ERPF and GFR significantly with a maximumdecline at the end of the clearance study. Iloprost infusionabolished the CsAinduced decrease in ERPF, but had no effecton the CsA-induced decrease in GFR, leading to a significantdecline in FF. Renal clearance of lithium (CLi), used as anindex of proximal tubular outflow, decreased in parallel withGFR after CsA intake, with no additional effects of iloprost.Iloprost infusion decreased blood pressure and increased heartrate. CONCLUSION.: Infusion of iloprost causes systemic and renal vasodilatation,but has no effect on the CsA-induced decrease in GFR and C_Liin stable renal transplant recipients.     

Impact of long-term immunosuppression with cyclosporin A on serum lipids in stable renal transplant recipients

Abstract. To determine the impact of long-term immunosuppression on serum lipids in stable renal graft recipients we measured serum lipids and apolipoprotein B concentrations in 20 patients receiving therapy with cyclosporin (CsA) and low-dose prednisolone (CsA/P) and in 18 patients on therapy with azathioprine and maintenance steroids (Aza/P). The patients were matched for age, body mass index, primary renal disease and dose of prednisolone, but not for the duration in transplantation and serum creatinine concentration. Triglyceride concentrations were significantly higher in the CsA/P group than in Aza/P-treated patients: 2.62 ± 0.35 vs 1.62 ± 0.23 mmol/l ( P < 0.05). Similarly, total cholesterol (C) levels were significantly more elevated in the CsA/P recipients than in the other group: 7.4410.32 vs 5.84 ± 0.25 (F<0.02). CsA/P patients had higher serum levels of LDL-C (4.79 ± 0.20 vs 3.43 ± 0.19 mmol/l ( P < 0.001) and apolipoprotein B concentrations (191 ± 13 vs 128 ± 9 mg/dl; P < 0.001). CsA/P and Aza/P recipients had similar concentrations of HDL-C (1.73 ± 0.13 vs 1.52 ± 0.09 mmol/l; NS). We conclude that in stable renal graft recipients with good transplant function long-term immunosuppression with CsA/P is associated with a more atherogenic lipid status than therapy with Aza/P.     

Impact of long-term immunosuppression with cyclosporin A on serum lipids in stable renal transplant recipients

To determine the impact of long-term immunosuppression on serum lipids in stable renal graft recipients we measured serum lipids and apolipoprotein B concentrations in 20 patients receiving therapy with cyclosporin (CsA) and low-dose prednisolone (CsA/P) and in 18 patients on therapy with azathioprine and maintenance steroids (Aza/P). The patients were matched for age, body mass index, primary renal disease and dose of prednisolone, but not for the duration in transplantation and serum creatinine concentration. Triglyceride concentrations were significantly higher in the CsA/P group than in Aza/P-treated patients: 2.62±0.35 vs 1.62±0.23 mmol/l (P<0.05). Similarly, total cholesterol (C) levels were significantly more elevated in the CsA/P recipients than in the other group: 7.44±0.32 vs 5.84±0.25 (P<0.02). CsA/P patients had higher serum levels of LDL-C (4.79±0.20 vs 3.43±0.19 mmol/l P<0.001) and apolipoprotein B concentrations (191±13 vs 128±9 mg/dl; P<0.001). CsA/P and Aza/P recipients had similar concentrations of HDL-C (1.73±0.13 vs 1.52±0.09 mmol/l; NS). We conclude that in stable renal graft recipients with good transplant function long-term immunosuppression with CsA/P is associated with a more atherogenic lipid status than therapy with Aza/P.     

Serial estimation of glomerular filtration rate in children after renal transplant

Evaluation of serial monthly estimated glomerular filtration rate (eGFR) may be useful for studying pediatric renal allograft outcome. To determine the validity of this approach, we reviewed our single-center experience in pediatric renal transplant recipients to determine the effect of risk factors for renal allograft failure on eGFR. Clinical parameters recorded monthly through 5 years post transplant allowed serial assessment of eGFR. Monthly clinical data included height, weight, serum creatinine, cumulative number of acute rejection episodes, cyclosporine dose, and cyclosporine trough levels. From these data, eGFR was calculated monthly for each patient using the Schwartz formula. Time post transplant was grouped in 6-month intervals and plotted against mean eGFR to compare eGFR in patients grouped by demographic and clinical factors; 1,786 monthly data sets from 6 months post transplant (n=76 patients) to 5 years post transplant (n=25 patients) were analyzed. Overall mean eGFR from 6 months to 1 year was 75 ml/min per 1.73 m² and from 4.5 to 5 years 46 ml/min per 1.73 m². eGFR was lower at all time intervals for recipients of cadaver versus living-related donor grafts, and patients with ≥1 versus 0 acute rejections (P<0.01). After 1 year, eGFR was lower in black patients compared with white or Hispanic patients (P<0.01). Cyclosporine dose greater than 5 mg/kg per day was associated with better early and worse late graft function. These results are similar to those reported in multi-center studies using the outcome variable of graft failure and suggest that serial eGFR may be valid as an outcome variable to study chronic renal allograft dysfunction in children. Received: 1 March 1999 / Revised: 7 June 1999 / Accepted: 10 June 1999     

Kidney dimensions at sonography are correlated with glomerular filtration rate in renal transplant recipients and in kidney donors

The gold standard to assess renal function is the measurement of glomerular filtration rate (GFR). For practical reasons, renal function is often evaluated from serum creatinine (S Cr) or cystatin C (S Cys), and GFR is predicted from SCr. Ultrasound scanning of the kidneys is used only to evaluate renal morphology. The aim of this study was to evaluate the relationship between sonographic renal dimensions and GFR in renal transplant recipients and in kidney donors. GFR (urinary clearance of (99m)Tc-DTPA), S Cr, and S Cys were measured in 33 donors (28 females [F], 5 males [M]; SCr, 0.81-1.90 mg/dL) and 30 recipients (8 F, 22 M; SCr, 0.96-2.42 mg/dL). GFR was also predicted using the Cockcroft and Gault (CG) formula and with the simplified Modification of Diet in Renal Disease (MDRD) formula. Length, width, and depth of kidneys and renal sinus were measured using renal sonography. Among sonographic measurements, kidney length showed the best correlation with GFR. A closer correlation with GFR was found in donors (r = 0.639; P < .00007) than in recipients (r = 0.511; P < .005). In either case, the correlation of kidney length with GFR was greater than that of S Cr or S Cys, and similar to that of CG or MDRD GFR. Accuracy of kidney length as an indicator of GFR impairment was not statistically different from laboratory tests. Only in donors did CG show better accuracy. In conclusion, renal dimensions at sonography closely correlated with GFR. Thus, renal sonography can give information also on the function of the renal graft and of the remaining kidney of living donors.