M. Mehdi

Cystatin C-based equations in renal transplantation: moving toward a better glomerular filtration rate prediction?

Creatinine-based glomerular filtration rate (GFR) estimators perform poorly in renal transplant recipients. Cystatin C might be a better alternative to serum creatinine in assessing renal graft function. We compared several cystatin C-based equations with the modification diet renal disease (MDRD) equation in 120 adult renal transplant recipients for whom the GFR was measured by the gold standard inulin clearance. Mean inulin-measured GFR was 52.6 mL/min/1.73 m2 (range, 13–119). The Hoek, Rule, Le Bricon, and Filler cystatin C-based formulas showed significantly better performances (accuracy 30% of 82%, 81%, 78%, and 71%), than the MDRD equation (58%, Mac Nemar test, P<0.01). Sensitivity to detect a GFR below 60 mL/min/1.73 m2 was significantly higher for the Hoek and the Rule equations (0.95, 95% CI 0.91–1) than for the MDRD equation (0.76, 95% CI 0.67–0.85). These data confirm that cystatin C as a GFR marker offers significant advantages over creatinine in renal transplantation.

Creatinine-based GFR predicting equations in renal transplantation: reassessing the tubular secretion effect

BACKGROUND The real utility of blocking the tubular secretion of creatinine with cimetidine in order to ameliorate the prediction of renal graft function is questionable, particularly in the context of an increasing diffusion of the Modification of Diet in Renal Disease (MDRD) study equation. We have compared the impact of cimetidine on the performances of the Cockcroft-Gault (C-G) and MDRD equations in 56 renal transplant patients with an estimated glomerular filter rate (GFR) >30 mL/min/1.73 m(2) for whom true GFR was directly measured by inulin clearance. METHODS Serum creatinine concentration (SCr) was measured [isotope dilution mass spectrometry (IDMS) traceable enzymatic assay] at the beginning of the inulin clearance procedure and 2 days later, after three oral cimetidine doses of 800 mg every 12 h. Predictive and diagnostic performances of the re-expressed MDRD and C-G formulas were compared before and after cimetidine intake. RESULTS Mean SCr (+/-SD) increased from 120 micromol/L (+/-34) before to 154 micromol/L (+/-47) after cimetidine. The beneficial effect of cimetidine was significant only on the accuracy of the C-G formula (accuracy 30% post-cimetidine of 93 and 79% for the C-G and MDRD equations, respectively). Likewise, while a higher proportion of patients were correctly staged using the chronic kidney disease classification after cimetidine with the C-G equation (59% before and 68% after), no improvement was seen with the MDRD formula (59 vs 57%). For both equations, receiver operating characteristic curves analysis showed only a marginal gain in GFR prediction. CONCLUSION Our data do not support the use of a cimetidine-based strategy for the evaluation of renal graft function in the clinic, particularly when the GFR is estimated by the MDRD equation.

Mycophenolate sodium dosing in combination with tacrolimus: pharmacokinetic evaluation of a novel regimen in de novo tacrolimus-treated kidney transplant patients.

BACKGROUND There are no clear guidelines concerning the appropriate dose of mycophenolate acid (MPA) to be used in association with tacrolimus. When MPA is given at an approved fixed dose in cyclosporine-treated patients, initial systemic under exposure is frequent and associated with the occurrence of acute rejection. We pharmacologically evaluated in tacrolimus-treated recipients a novel dosing regimen of MPA with an initial high dose followed by a gradual decrease over time. METHODS 15 de novo tacrolimus-treated kidney transplant patients were administered mycophenolate sodium at the dose of 720 mg b.i.d. for the first week post-transplant, 540 mg b.i.d. until Day 30, and then 360 mg b.i.d. until Day 90. MPA exposure was evaluated by the 12 h area under MPA concentration versus time curve (AUC) determined at Days 2, 7, 15, 30 and 90 post-transplant. RESULTS Median MPA AUC was constantly within the therapeutic window of 30 - 60 mg/l × h throughout the three months of evaluation. More than 75% of patients had a MPA AUC above 30 mg/l × h at Day 2 and Day 7 post-transplant. CONCLUSION This exploratory study suggests that such a dosing regimen of mycophenolate sodium might quickly offer and sustain an optimal exposure to MPA in tacrolimus-treated kidney transplant patients.

[Telemedicine: an unfruitful experience of tele-expertise in nephrology].

INTRODUCTION We developed a new system of medical tele-expertise to improve detection and care of chronic renal failure by way of a better communication between general practitioners and specialists. It has been known for long that the incidence of chronic renal failure is increasing while cost of its treatment is very high. Unfortunately, late referral of patients with kidney diseases remains around 30%. Our goal was to help physicians to get access to nephrologists, hence to improve the cure of renal diseases. An early treatment of nephropathies may avoid the evolution to the stage of dialysis. METHODS We created a website with the technical support of the firm Unimedecine. It allowed a secure and fast exchange of medical data, all about the case of a one patient. RESULTS General practitioners seemed enthusiastic, but at the end, only a few of them did use the website. The number of connexion remained low throughout a 3-year experience. Questions were about advices but no progressive nephropathy was discovered. The cost of the website was a prohibitive 75 000 euros for 3 years. Therefore, we had no choice that to close the experience. DISCUSSION Telemedicine needs juridical rules and specific finances to work on a long run.

Télémédecine : une expérience infructueuse de télé-expertise en néphrologie

INTRODUCTION We developed a new system of medical tele-expertise to improve detection and care of chronic renal failure by way of a better communication between general practitioners and specialists. It has been known for long that the incidence of chronic renal failure is increasing while cost of its treatment is very high. Unfortunately, late referral of patients with kidney diseases remains around 30%. Our goal was to help physicians to get access to nephrologists, hence to improve the cure of renal diseases. An early treatment of nephropathies may avoid the evolution to the stage of dialysis. METHODS We created a website with the technical support of the firm Unimedecine. It allowed a secure and fast exchange of medical data, all about the case of a one patient. RESULTS General practitioners seemed enthusiastic, but at the end, only a few of them did use the website. The number of connexion remained low throughout a 3-year experience. Questions were about advices but no progressive nephropathy was discovered. The cost of the website was a prohibitive 75 000 euros for 3 years. Therefore, we had no choice that to close the experience. DISCUSSION Telemedicine needs juridical rules and specific finances to work on a long run.

Severe secondary hyperparathyroidism in patients on haemodialysis is associated with a high initial serum parathyroid hormone and beta-CrossLaps level: Results from an incident cohort

Background Secondary hyperparathyroidism (SHPT) is a frequent complication of renal disease and most commonly occurs in patients on haemodialysis (HD) with metabolic, vascular, endocrine, and bone complications. The aim of this study was to analyze the evolution of mineral metabolism parameters during the first 36 months of HD treatment and identify the initial factors associated with severe SHPT. Methods Serum parathyroid hormone (PTH), calcium and phosphate levels were measured monthly; bone-specific alkaline phosphatase (b-ALP) and beta-CrossLaps (CTX) were measured biannually. Severe SHPT was defined as the need for cinacalcet treatment. Patients with less than 24 months of follow-up were excluded. Results One hundred thirty-three incident HD patients were included. Baseline mean PTH was 275 ± 210 pg/mL. After an initial drop at the third month (172 ± 133 pg/mL), the serum PTH level progressively increased to the maximum at 36 months (367 ± 254 pg/mL). This initial drop was associated with the initial correction of both hypocalcaemia and hyperphosphataemia. Serum CTX and b-ALP revealed no significant changes over time. Severe SHPT was observed in 18% of patients and was associated with higher mean calcaemia and phosphataemia. In logistic regression, the initial factors associated with the risk of severe SHPT were: female sex, higher baseline PTH and CTX values. A receiver operation characteristic curve analysis identified a cut-off value of >374 pg/mL for baseline PTH and >1.2 μg/L for CTX for increased risk of developing severe SHPT. The relative risk of developing severe SHPT was 3.7 (1.8–7.5, p = 0.002) for high baseline CTX, 4.9 (2.4–9.7, p = 0.001) for high baseline PTH, and 7.7 (3.6–16, p< 0.0001) when both criteria were present. Conclusion After an initial drop, a progressive increase in the serum PTH level during the first 3 years of HD treatment was observed despite aggressive therapy. High baseline levels of PTH and CTX increased the risk of developing severe SHPT.

Article originalTélémédecine : une expérience infructueuse de télé-expertise en néphrologieTelemedicine: An unfruitful experience of tele-expertise in nephrology

INTRODUCTION We developed a new system of medical tele-expertise to improve detection and care of chronic renal failure by way of a better communication between general practitioners and specialists. It has been known for long that the incidence of chronic renal failure is increasing while cost of its treatment is very high. Unfortunately, late referral of patients with kidney diseases remains around 30%. Our goal was to help physicians to get access to nephrologists, hence to improve the cure of renal diseases. An early treatment of nephropathies may avoid the evolution to the stage of dialysis. METHODS We created a website with the technical support of the firm Unimedecine. It allowed a secure and fast exchange of medical data, all about the case of a one patient. RESULTS General practitioners seemed enthusiastic, but at the end, only a few of them did use the website. The number of connexion remained low throughout a 3-year experience. Questions were about advices but no progressive nephropathy was discovered. The cost of the website was a prohibitive 75 000 euros for 3 years. Therefore, we had no choice that to close the experience. DISCUSSION Telemedicine needs juridical rules and specific finances to work on a long run.