In essential hypertension, a change in the renal resistive index is associated with a change in the ratio of 24-hour diastolic to systolic blood pressure.

An increase in the renal resistive index (RRI) in patients with essential hypertension (EH) predicts deterioration in renal function. In patients with EH, changes in hemodynamic parameters significantly affect the RRI. This study aimed to define changes in Ambulatory Blood Pressure Monitoring (ABPM) parameters that are significantly associated with a change in RRI in patients with EH. We evaluated ABPM and the RRI in 96 patients with EH without organ extrarenal changes at baseline and after two years of follow-up. The relationships between changes in ABPM parameters and the RRI over the period were evaluated. After two years of follow-up, the increase in RRI was consequential. Simultaneously, 24-h systolic blood pressure increased significantly and 24-h diastolic blood pressure decreased. In the whole group and in the group with calculated cystatin C clearance (eGFRcyst) >/=90 ml/min/1.73 m2, the change in RRI significantly negatively correlated with the change in the ratio of 24-h diastolic to systolic blood pressure (D/S ratio), but also with the change in 24-h pulse blood pressure. However, in patients with eGFRcyst>90 ml/min/1.73 m2, only the change in the 24-h D/S ratio significantly correlated with the change in RRI. Based on the backward stepwise regression analysis, the change in RRI was significantly dependent only on the change in 24-h D/S ratio and not on the change in 24-h pulse pressure. A change in the ratio of diastolic to systolic pressure better reflects a change in RRI than a change in pulse pressure.

Hyponatremia in spinal cord injury patients: new insight into differentiating between the dilution and depletion forms.

STUDY DESIGN: This is a retrospective study. OBJECTIVES: The objectives of this study were to present a new model for differentiating between the dilution and depletion forms of hyponatremia in patients in the postacute phase after spinal cord injury (SCI), and to identify possible etiological factors contributing to hyponatremia in these patients. SETTING: University Hospital Motol, Prague, Czech Republic. METHODS: Eighty-seven of 352 patients hospitalized in 2008-2012 in the Spinal Cord Unit were hyponatremic. Seventy-four patients had SNa+=130-135 mmol l(-1) and 13 patients had SNa+ below 130 mmol l(-1). We propose a simple model of an electrolyte solution in which the Na(+) concentration is higher than the Cl(-) concentration, making it possible to compare the effects of dilution and depletion of Na(+) and Cl(-) on the Na(+) concentration. The depletion of Na(+) and Cl(-) leads to a significant increase in the Na(+)/Cl(-) ratio, with the Na(+)-Cl(-) value remaining unchanged. Dilution with water results in a decrease of Na(+)-Cl(-) with the Na(+)/Cl(-) ratio remaining unchanged. RESULTS: In patients with SNa+ below 130 mmol l(-1), hyponatremia was consistent with the depletion model in 46% and with the dilution model in 32%. In patients with SNa+ ranging between 130 and 135 mmol l(-1), the respective rates were 34 and 12%. CONCLUSION: Examination of SNa+-SCl- and SNa+/SCl- in patients with SCI could be helpful in considering whether hyponatremia is consistent either with the NaCl dilution model or with the NaCl depletion model. Further studies are needed for more accurate interpretation of the results, particularly with respect to volume and acid-base disorders.

[End stage of chronic kidney disease and metabolic acidosis]. / Konecné stadium chronického onemocnení ledvin a metabolická acidóza.

Renal function disorder is inevitably associated with metabolic acidosis. An adult produces approximately 1 mmol of acids/kg of body weight every day (3 mmol/kg in children), derived from metabolization of proteins from food. Development of metabolic acidosis in patients with kidney disease is based on accumulation of acids and insufficient production of bicarbonates; alkaline loss represents a marginal issue here limited to patients with type II renal tubular acidosis only. The prevalence of this disorder increases with declining glomerular filtration (GFR) from 2% in patients with GFR 1.0-1.5 ml/s/1.73 m2 to 39% in patients with GFR < 0.3 ml/s/1.73 m2 or, alternatively, to 19% in patients with GFR 0.25-0.3 ml/s/1.73 m2. Notwithstanding the primary cause of the renal disease, declining GFR is associated with compensatory increase in ammoniac production in residual nephrons. This is an adaptive mechanism aimed at maintaining sufficient elimination of acids despite reduced volume of functional tissue. However, an increased ammoniac production simultaneously becomes a stimulus for activation of the complement via an alternative route and is thus one of the factors contributing, through this induced inflammation, to progression of tubular interstitial fibrosis that subsequently leads to further GFR reduction. Metabolic acidosis has a number of severe adverse effects on the organism, e.g. deterioration of kidney bone disease through stimulation of bone resorption and inhibition of bone formation, inhibition of vitamin D formation, increased muscle catabolism, reduced albumin production, glucose metabolism disorder, increased insulin resistance, reduced production of thyroid hormones, increased accumulation of ß2-microglobulin etc. Non-interventional studies suggest that alkali supplementation may slow down progression of chronic nephropathies. However, this approach, safe and inexpensive, has not been widely implemented in clinical practice yet. With respect to dialyzed patients, abnormal levels of bicarbonates are associated with increased mortality. Both metabolic acidosis and alkalosis, rather regularly seen in a considerable number of patients, have a negative effect on patient survival. Alkali substitution from a dialysis solution is the main pillar of metabolic acidosis management in patients on hemo- as well as peritoneal dialysis. Available technologies allow individualization of the treatment and this should be observed.

Plasma adrenomedullin and subclinical cardiorenal syndrome in patients with type 2 diabetes mellitus.

OBJECTIVE: To evaluate whether plasma adrenomedullin is involved in the previously reported significant inverse correlation between left ventricular (LV) end-diastolic pressure (peak velocity of early transmitral flow/peak velocity of early diastolic mitral annular motion ratio [E/E' ]) and estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes mellitus, mild-to-moderate renal function impairment and LV relaxation impairment (E'≤7.1 cm/s). METHODS: Plasma adrenomedullin concentration, E/E' and eGFR were assessed in 82 patients with type 2 diabetes. RESULTS: Plasma adrenomedullin concentration was positively correlated with eGFR in patients with or without LV relaxation impairment, and inversely correlated with E/E' in patients with LV relaxation impairment. Multivariate linear regression analysis supported a role for plasma adrenomedullin in the association between E/E' and eGFR. CONCLUSION: These results support the hypothesis that adrenomedullin modulates the interaction between the heart and kidneys in early subclinical cardiorenal syndrome in patients with type 2 diabetes mellitus.

The association between left ventricular diastolic function and a mild-to-moderate decrease in glomerular filtration rate in patients with type 2 diabetes mellitus.

This prospective study evaluated the relationship between echocardiography parameters of left ventricular (LV) diastolic function and mild-to-moderate renal function impairment in 82 patients with type 2 diabetes mellitus. The mean age of the patients was 61.1 years. A significant correlation was found between estimated glomerular filtration rate (eGFR) and the ratio of peak velocity of early transmitral flow (E) to peak velocity of early diastolic mitral annular motion (E'). Cluster analysis revealed two subgroups of patients with different E' values but comparable eGFRs. The correlation between eGFR and E/E' was significant in 38 patients with E' ≤ 7.1 cm/s, but not significant in 44 patients with E' > 7.1 cm/s. The results suggest that the deterioration of LV relaxation (E') represents the underlying condition for the association between mild-to-moderate renal function impairment and the non-invasive parameter of LV end-diastolic pressure (E/E'), in patients with type 2 diabetes without any previous cardiovascular event and with well-controlled blood pressure.

[Pathophysiology of metabolic acidosis in patients with reduced glomerular filtration rate according to Stewart-Fencl theory]. / Patofyziologie vzniku metabolické acidózy u pacientu se snízenou glomerulární filtrací z hlediska Stewartovy-Fenclovy teorie.

AIM: Metabolic acidosis is a regular sign of renal insufficiency. Conventional assessment of acid-base balance using Henderson-Hasselbalch equation does not make identification of the cause of metabolic disorders possible as the serum HCO3- concentration might only reflect changes to the overall plasma ion spectrum. Therefore, we used the Stewart-Fencl approach that is based on a more detailed physical and chemical analysis and that showed that changes to serum HCO3- concentration are closely related to parameters not usually monitored in connection to acid-base balance. PATIENT GROUP AND METHODOLOGY: We performed a single measurement of arterial or capillary blood pH and pCO2 in 69 non-dialysed patients with glomerular filtration rate ranging from 0.04 to 0.88 ml/s/1.73 m2 according to MDRD, standard calculation of serum HCO3- concentration using Henderson-Hasselbalch equation was carried out, and serum albumin and ion concentrations (Na+, K+, Cl, Pi) plus creatinine and urea concentrations were determined from venous blood. RESULTS: Metabolic acidosis was present in 47 patients ([S-HCO3-] < 22 mmol/l) with the mean [S-HCO3-] value of 19.6 mmol/l for the entire group. We proved a statistically significant correlation between [S-HCO3-] and [SID] (p < 0.001), and between [S-HCO3-] and the individual [SID] determining factors: [Na+-Cl-], [UA- ], [Pi-], [K+] (p < 0.01). CONCLUSION: Reduction in [S-HCO3-] in non-dialysed patients with reduced glomerular filtration is predominantly associated with a decrease in [Na+-Cl-] difference, the quantitative contribution of which to metabolic acidosis is more significant than the strong acids retention. In addition to [S-Cl-] increase, [S-Na+] reduction too has a major role in reducing the [Na+-Cl-] difference.

[Liver transplantation and peri-operative changes to renal function]. / Transplantace jater a perioperacní zmeny renálních funkcí.

THE AIM OF THE STUDY: Was to analyze in detail perioperative changes of renal function during orthotopic liver transplantation (OLT) and to identify risk factors, that were associated with the need of renal replacement therapy (RRT) during the first week after liver transplantation. METHODS: Prospective study of 50 consecutive patients undergoing OLT was performed. Selected laboratory and clinical parameters were monitored prior to the procedure, after reperfusion, at the end of the procedure, and at 12 hours after the procedure. In the first post-transplant week, necessity to use RRT in the presence of acute kidney injury was monitored and the analysis of risk factors for the need for RRT was performed. Patient survival, graft function, need for dialysis and selected laboratory parameters were assessed at one year post-transplant. RESULTS: During OLT, there was an increase in S(cr) and S(urea), which persisted as late as 12 hours post-transplant. There was a decrease in U(cr) and U(urea) and an increase in S(Na) and S(K). During the procedure any increase in S(cyst) were observed, increase the values were recorded 12 hours after surgery. S(bili) level decreased. There was a rise in the urinary levels of total protein, albumin and beta2-microglobulin. U(prot)/U(cr) increased significantly after reperfusion, with a peak after the procedure. At 12 hours after the procedure, there was a decrease in U(prot)/U(cr), but the values were still many times higher than those seen preoperatively. RRTwas necessary in 14% cases. Risk factors for acute kidney injury requiring RRT included a higher APACHE score, higher BMI, higher preoperative S(cr) and S(urea), hepatorenal syndrome pretransplant, blood loss and intraoperative hemodynamic instability, postoperative complications and dysfunction of the liver graft. One year after OLT, there was no difference in followed laboratory values between patients requiring postoperative RRT and others; no patient was treated with dialysis. CONCLUSION: OLT has a major impact on glomerular and tubular renal functions. Our data suggest that patients surviving acute renal injury treated with RRT in the early postoperative period have a high chance of restoring renal function. A sensitive marker of renal injury during OLT seems to be perioperative proteinuria.

[Possibilities of evaluation of changes of glomerular filtration rate estimated on the basis of predicting formulas]. / Moznosti posouzení zmen glomerulární filtrace na podklade predikcních formulí.

INTRODUCTION: Estimation of changes of glomerular filtration rate based on accurate measurement (GFR) and that based on predicting formulas (eGFR) could differ significantly. In this study we have tried to analyse the relationship between (eGFR)t2/(eGFR)t1 and (GFR)t2/(GFR)t1 (where t1 and t2 denote the time at the beginning and the end of the follow-up interval). METHODS: Renal clearance of inulin (Cin) was repeatedly examined in 32 patients suffering from chronic renal impairment (S(Cr) = 231 +/- 70 micromol/l). Estimated GFR (eGFR) was calculated on the basis of Modification of Diet in Renal Disease (MDRD) and Cockcroft-Gault (CG) equations. RESULTS: A significant relationship between (MDRD)t2/(MDRD)t1 and (Cin)t2/(Cin)t1 (r = 0.544, p = 0.0028, R2 = 0.295) as well as between (CG)t2/(CG)t1 and (Cin)t2/(CG)t1 (r = 0.556, p = 0.0026, R2 = 0.309) was found. Average difference between (MDRD)t2/(MDRD)t1-(Cin)t2 /(Cin)t1 was 0.017 +/- 0.17 and that of (CG)t2 /(CG)t1-(Cin)t2/ (Cin)t1 was 0.024 +/- 0,18. Within +/- 0.20 of the difference (eGFR)t2/(eGFR)t1-(Cin)t2 /(Cin)t1 59 % values were found and within +/- 0.30 of this difference 75% values were recorded. Highly significant relationship was found between (MDRD)t2/(MDRD)t1 and (CG)t2/(CG)t1 (r = 0.991; p = 0.0001; R2 = 0.983). CONCLUSION: Considering these preliminary findings, predicting formulas are not sensitive sufficiently to by able to detect GFR changes lower than 30% of initial value.

Obesity and adiponectin after kidney transplantation.

Obesity and hyperlipidaemia are found very frequently after kidney transplantation (Tx) and may represent independent risk factors for development of atherosclerosis and chronic allograft nephropathy. In a prospective metabolic study, we monitored, a total of 68 obese transplant patients [body mass index (BMI) > 30 kg/m2] with dyslipidaemia over a period of 24 months. We compared the findings of a new therapeutic regimen 1 year (start of the study) and 2 years after renal transplantation. Based on a Subjective Global Assessment Scoring Sheet, we started at the end of the first year with an individualized hypoenergic-hypolipidaemic diet (IHHD). Subsequently, after corticoid withdrawal, IHHD was supplemented regularly with statins (atorvastatin 10-20 mg/day)) and followed-up for 2 years. All patients were on a regimen of cyclosporin A or tacrolimus and mycophenolate mofetil. During the study period, there was a significant decrease in BMI (p < 0.025) and an increase of the adiponectin level (p < 0.01). Long-term therapy was associated with a significant decrease in serum leptin (p < 0.01) and lipid metabolism parameters (p < 0.01). Inulin clearance, mean systolic and diastolic blood pressure, proteinuria, lipoprotein(a) and apo-lipoprotein E isoforms did not differ significantly. Based on our results, we assume that obesity and hyperlipidaemia after renal transplantation can be treated effectively by modified immunosuppression (corticosteroid withdrawal), statins and long-term diet (IHHD). The increased level of adiponectin may be a marker of reducing atherosclerotic and chronic allograft nephropathy processes.

[Glomerular filtration rate prediction formulas in obese persons with chronic renal impairment]. / Moznosti posouzení glomerulární filtrace na podklade predikacních vzorcu obézních jedincu s chronickým renálním onemocnením.

BACKGROUND: The glomerular filtration rate (GFR) could be estimated on the basis of serum creatinine concentration (Scr) and some simple variables and demographic data. In clinical practice the most used methods for GFR estimation are Cockcroft-Gault (CG) formula and abbreviated MDRD equation (MDRD abr). The aim of this study was to evaluate how far obesity could affect GFR estimation based on the above formulas. METHODS AND RESULTS: In 291 patients with chronic renal impairment (S(cr) 45-489 micromol/l) GFR was examined on the basis of renal inulin clearance (C(in)) and estimated using MDRD abr and CG (without correction for body surface area-BSA and CG corrected for BSA) (CGkorig). The group of nonobese patients (A) consisted of 229 patients (BMI <30 kg/m2) and the group of obese patients (B) consisted of 62 patients (BMI 30 kg/m2). The values of r (r2) for MDRD abr, CG and CG(korig) in group A of patients was as follows: 0.893 (0.797), 0.810 (0.651), 0.853 (0.727) and 0.853 (0.727). In obese patients (group B) the corresponding values were as follows: 68.3% (82.6%), 28.6% (39.7%) and 46% (61.9%). Predicted GFR within 30% and 50% of C(in) (in brackets), CG and CG(korig) (for BSA) were for group A: 70.2% (87.3%), 50.4% (67.1%) and 55.7% (75%) and for group B: 68.3% (82.6%), 28.6% (39.7%) and 46% (61.9%). The ratio MDRD abr/Cin did not correlate with BMI. A weak, but significant correlation was found between BMI and CCcorig/Cin ratio (r=0.22, p<0.05). CONCLUSIONS: The obtained results suggest that estimation of GFR based on MDRD abr is not influenced by obesity. Estimation of GFR based on CG formula is significantly affected by obesity. A weak but significant relation could by found between CGkorig/Cin and BMI.

[Effects of specific cycloxygenase-2 inhibition on the renal functions of ederly patients with renal function impairment]. / Vliv specifické inhibice cyklooxygenázy 2 na ledvinové funkce u starsích pacientu s poruchou ledvinové funkce.

BACKGROUND: Elderly patients suffering from nociceptive pain of locomotive organs and concomitantly from renal impairment represent a target population for painkilling drugs. That is why they are predisposed to nephrotoxic effects non-steroidal anti-inflammatory drugs. The aim of our study was to evaluate cycloxygenase-2 (COX-2) inhibition effect on renal function in elderly with moderate impairment of renal function. METHODS AND RESULTS: Based on 24-h urine collection we assessed creatinine clearance (C(Cr), fractional excretion of sodium (FE(Na)), potassium (FE(K)), chloride (FE(Cl)), osmotic active solutes (FE(OSM)) and 24h urinary excretion of prostaglandin PGE2 and PGF(2 alpha). Under conditions of sub-maximal water load fractional excretion of electrolytes, inulin clearance (C(in)), serum cystatin C (S(cyst)) were assessed. In addition basal and stimulated plasma renin activity (PRA) and plasma aldosteron (P(aldo)) were examined. Using comparison of parameters before and at the end of 7-days rofecoxib treatment we found out C(in) 0,82 +/- 0,34 vs 0,74 +/- 0,18 ml/s/l,73 m2, FE(Na) 1,0 +/- 0,3 vs 1,2 +/- 0.4 (p=0,02), FE(OSM) 2.9 +/- 0,7 vs 3,7 +/- 1,2% (p=0,03), U(PGE2 alpha),V 663 +/- 528 vs 414 +/- 195 (p=0,059), U(PGD2) V (559 +/- 625) vs 205 +/- 174 eta g/24h (p=0,02), stimulated PRA 0.94 +/- 0,73 vs 0,4 +/- 0,27 +/- pg/l/h (p=0,019), P(aldo) 104,56 +/- 50,15 vs 56,94 +/- 27,08 eta g/l/h (p=0,008). CONCLUSIONS: Short-term COX-2 inhibition in patients with moderate renal impairment was associated with significant decrease of tubular transport of sodium, without changing GFR and water excretion.

[Obesity and progression of chronic renal insufficiency: a Czech long term prospective double-blind randomised multicentre study]. / Obezita a progrese chronické renální insuficience: ceská dlouhodobá prospektivní randomizovaná dvojite slepá multicentrická studie.

Obesity represents one of serious risk factors in chronic renal failure patients (CRF). In three years prospective double-blind randomised multicentre study we monitored 66 patients with advanced chronic renal insufficiency, GFR 24.4-37.3 ml/min (0.41 to 0.62 ml/s) and BMI > or = 30 kg/m2 on long term low-protein diet (0.6 P/kg BW/day) and ACEI + ARB. Thirty four randomly selected patients (group I) were treated with keto amino acids, 32 patients in control group (group II) with placebo. During the study period significant decrease of BMI, proteinuria and slowing in progression of renal failure (C(in)) were found. Significant changes were also noted in parameters of albumin and transferrin (p < 0.02), leucin and WQ (p < 0.01 - p < 0.02), glycaemia and HbA1c (p < 0.02), triglycerides (p < 0.01), leptin and ObRe (p < 0.01) and selected parameters of endothelial dysfunction (ET1, p < 0.02, TGFbeta1, p < 0.02). Significantly also decreased PTH value (p < 0.01). Successful treatment of obesity can significantly improve long term prognosis in CRF patients.

Effect of rofecoxib on the glomerular filtration rate, proteinuria and the renin-angiotensin-aldosterone system in elderly subjects with chronic renal impairment.

UNLABELLED: Considering the increasing popularity and prescribing of specific COX-2 inhibitors, a new class of NSAIDs lacking gastrointestinal side effects, the evaluation of their effects on renal function has become very important. OBJECTIVE: The aim of the study was to evaluate the effect of rofecoxib on GFR, proteinuria and the renin-angiotensin-aldosterone system (RAAS) in elderly patients with chronic renal impairment under controlled conditions of water and salt intake. SUBJECTS: There were ten patients (average age 67 years, range 53 - 80 years) with analgesic or vascular nephropathy (average GFR 54 ml/min/1.73 m2, range 30 - 79 ml/min/ 1.73 m2) given 25 mg rofecoxib daily for seven days under balanced conditions of water and sodium metabolism (salt intake 6 - 8 g/24 hours). METHODS: The effect of rofecoxib on GFR measured using inulin clearance (C(in)), creatinine clearance (C(Cr)) serum cystatin C concentration (S(cystatin)), tubular creatinine secretion (using the ratio C(Cr)/C(in)), 24-hour urinary excretion of albumin (U(alb)V) and prostaglandins (U(PGE2)V and U(PGF2alpha)V), basal and stimulated plasma renin activity (PRA) and serum aldosterone concentration S(aldosterone) was evaluated before and on Day 7 during rofecoxib treatment. RESULTS: Rofecoxib did not significantly change C(in), C(Cr), S(cystatin), C(Cr)/C(in) and U(alb)V. However, U(PGE2)V and U(PGF2alpha)V were decreased during rofecoxib administration (p = 0.059 and p = 0.024, respectively). Rofecoxib attenuated the stimulated rise of PRA and S(aldosterone) (p = 0.019 and p = 0.008, respectively). CONCLUSIONS: Short-term rofecoxib administration was not associated with significant change in GFR in elderly patients with moderate chronic renal impairment under conditions of balanced salt and water metabolism despite significant attenuation of RAAS activity. Since the C(Cr)/C(in) ratio did not change in our study, we assume rofecoxib to have no influence on creatinine tubular secretion.

[Long-term follow up of renal function after orthotopic liver transplantation]. / Dlouhodobé sledování funkce ledvin po ortotopické transplantaci jater.

BACKGROUND: Renal dysfunction in patients after the orthotopic liver transplantation (OLT) is frequent and it significantly contributes to the morbidity and mortality. The aim of our work was to assess the level of glomerular function (GFR) within the first to fifth year after OLT. METHODS AND RESULTS: Serum creatinine concentration (Skr), creatinine clearance (Ckr) and predicted value of creatinine clearance using the Cockcrofta a Gaulta formula (CG) were assessed in 75 patients. Normal values of the given parameters (Skr <110 umol/l, Ckr > or = 1.3 ml/s/1.73 m2) were found only in 16% of all patients. Significant decrease of GFR (Ckr < 0.5 ml/s/1.73 m2) was found in 24% of cases, acute renal failure, which required transitory haemodialysis developed in 4% of patients. In 60% of patients various degree of GFR decrease was found without the necessity of haemodialysis. CONCLUSIONS: Level of renal functions was not significantly related to the blood pressure or serum lipids concentration. An important factor appeared to be the level of renal function before OLT. Because the level of renal function after OLT can significantly influence the post transplantation development, regular follow up of GFR is recommended.

Estimation of glomerular filtration rate in obese patients with chronic renal impairment based on serum cystatin C levels.

BACKGROUND: Serum cystatin C (Scyst) has an obvious advantage in recognizing the initial stages of renal impairment. However, several recent studies suggest that Scyst may also be affected by some nonglomerular factors such as thyroid dysfunction, glucocorticoid administration or metabolic status of the diabetic patient. The aim of this study was to evaluate whether obesity could affect Scyst. PATIENTS AND METHODS: The study was performed in 33 patients (mean age 49.1 +/- 6.3 years) with chronic renal disease (Scr = 227 +/- 118 micromol/l) and BMI = 35.6 +/- 1.8 kg/m2, and in 78 patients (mean age 43.4 +/- 5.1 years) with chronic renal disease (Scr = 245 +/- 111 micromol/l) and BMI = 24.0 +/- 1.8 kg/m2. Glomerular filtration rate (GFR) was determined using renal inulin clearance (Cin) under conditions of stabilized plasma concentrations and water loading. Scyst was measured using immunonephelometry. For statistical evaluation, linear regression analysis and receiver-operating characteristic (ROC) curve analysis were used. RESULTS: A significant correlation (r = 0.956, p < 0.001) between l/Scyst and Cin was demonstrated in patients with BMI > or = 30 kg/m2 (Group A). Similarly, a significant correlation (r = 0.900, p < 0.001) between l/Scys and Cin was found in patients with BMI < 30 kg/m2 (Group B). There was no significant difference between the regression straight lines characterizing these relationships. ROC curve analysis (using a cut-off value for Cin = 30 ml/min/1.73 m2) did not show significant differences in AUC, sensitivity and specificity for Scyst between obese and nonobese patients. CONCLUSION: The results suggest that evaluation of GFR based on Scyst in obese patients need not differ from that in nonobese ones.

[A new method to estimate glomerular filtration rate based on serum concentration of creatinine, urea and albumin (MDRD, Modification of Diet in Renal Disease)]. / Nová metoda stanovení glomerulární filtrace na podklade sérové koncentrace kreatininu, mocoviny a albuminu (MDRD).

The equation developed from the MDRD (Modification of Diet in Renal Disease) study provides more accurate estimate of GFR than other commonly used equations. The aim of this study was to compare prediction of GFR based on MDRD and Cockcrof-Gault (CG) method. The study was performed in 111 patients (mean age 42 +/- 5 years) with chronic renal impairment (Scr = 281 +/- 83 micromol/l). The mean of MDRD was 0.480 +/- 0.345 ml/s/1.73 m2 and that of CG 0.608 +/- 0.336 ml/s/1.73 m2. The difference is highly significant (p < 0.0001). The mean of CG/MDRD ratio was 1.24 +/- 0.17. This ratio was significantly higher (p < 0.01) in obese patients (1.59 +/- 0.14 vs 1.22 +/- 0.09). The CG/MDRD ratio did not show relation to Scr. The results are in keeping with the assumption that the difference between MDRD and CG method cannot be explained by increased tubular secretion of creatinine in residual nephrons. Obesity seems to be on of the factors responsible for the difference between CG and MDRD values.