[Renal function and plasma dabigatran level measured at trough by diluted thrombin time assay]

Dabigatran etexilate (direct thrombin inhibitor) is effective in preventing embolic stroke in patients with atrial fibrillation. It does not require laboratory control, but given the high renal elimination, its measurement in plasma is important in renal failure. The objectives of the study were to verify the analytical quality of the diluted thrombin time assay for measurement of dabigatran plasma concentration (cc), correlate cc with classic coagulation assays, prothrombin time (PT) and activated partial thromboplastin time (APTT), and evaluate them according to the creatinine clearance (CLCr). Forty plasma samples of patients (34 consecutive and 6 suspected of drug accumulation) receiving dabigatran at 150 (n = 19) or 110 (n = 21) mg/12 hours were collected. Blood samples were drawn at 10-14 hours of the last intake. Dabigatran concentration was determined by diluted thrombin time (HemosIl DTI, Instrumentation Laboratory (IL). PT and APTT (IL) were performed on two fotooptical coagulometers, ACL TOP 300 and 500 (IL). DTI presented intra-assay coefficient of variation < 5.4% and inter-assay < 6%, linearity range 0-493 ng/ml. Patients' cc: median 83 (4-945) ng/ml. Individuals with CLCr in the lowest tertile (22.6-46.1 ml/min) showed significantly higher median cc: 308 (49-945), compared to the average 72 (12-190) and highest tertile, 60 (4-118) ng/ml. Correlation between cc and APTT or PT were moderate, r2 = 0.59 and -0.66, p < 0.0001, respectively. DTI test allowed us to quantify plasma dabigatran levels, both in patients with normal or altered renal function, representing a useful tool in clinical situations such as renal failure, pre surgery or emergencies.

Trimetazidine as an adjunct to standard hydration reduces the incidence of contrast-induced acute kidney injury in patients with renal insufficiency undergoing coronary angiography or percutaneous cardiac intervention: a systematic review and meta-analysis

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is a known complication after coronary angiography (CAG) or percutaneous coronary intervention (PCI). Clinical evidence suggests that trimetazidine (TMZ), an anti-ischemic drug, may prevent CI-AKI. We aimed to evaluate the role of trimetazidine in preventing CI-AKI in patients with pre-existing renal dysfunction undergoing CAG or PCI.

METHODS

We searched PubMed, Cochrane Library, EBSCOhost, Web of Science, and Google Scholar databases from January 2004 to January 2024. We reviewed RCTs involving participants aged ≥ 18 years with pre-existing renal insufficiency who underwent CAG or PCI. Outcomes should include the incidence of CI-AKI, adverse events, and changes in serum creatinine (Scr) levels at different time intervals. Two reviewers independently extracted the data, evaluated the quality and relevance of the studies, and graded the strength of evidence for each study through consensus.

RESULTS

Nine RCTs met the inclusion criteria and assessed the role of TMZ in patients with renal dysfunction who underwent CAG or PCI. All RCTs showed a significant decrease in the incidence of CI-AKI in the TMZ group compared to the control group (RR 0.36, 95% CI, [0.25, 0.52] P < 0.001). Changes in Scr at 24 h (SMD -0.33, 95% CI, [-0.56, -0.10], P = 0.01), at 48 h (SMD -0.27, 95% CI, [-0.46, -0.09], P = 0.01), and 72 h (SMD -0.32, 95% CI, [-0.56, -0.07], P = 0.01) were statistically significant in the TMZ group compared to the control group. However, the changes in Scr beyond 72 h following CAG or PCI were statistically insignificant in the TMZ group when compared to the control group (SMD -0.22, 95% CI, [-0.52, 0.09], P = 0.16). The incidence of adverse effects was lower in the TMZ group than in the control group, and the difference was statistically significant (RR 0.51, 95% CI, [0.29, 0.90]; P = 0.02).

CONCLUSION

The addition of TMZ to standard hydration protocols may offer a promising strategy for lowering the incidence of CI-AKI, adverse events, and postoperative SCr levels in patients with renal insufficiency within 72 h after CAG or PCI. However, large-scale RCTs are necessary to definitively establish the efficacy and safety of TMZ in patients with renal insufficiency after CAG or PCI.

Association of serum Nrf2 protein levels with disease activity and renal impairment in lupus nephritis

Introduction

We aimed to investigate the relationship between nuclear factor erythroid 2-related factor 2 (Nrf2) protein expression levels, lupus nephritis (LN) disease activity, and the degree of renal injury (based on the estimated glomerular filtration rate [eGFR]) in patients with LN.

Methods

We selected 40 healthy control participants and 102 patients with LN who were treated in the Second Hospital of Jilin University, China, for inclusion in this study. Patients with LN were classified into LN with high-eGFR and LN with low-eGFR groups. Nrf2 protein levels were measured in the serum and renal tissues of the participants in both groups to assess the correlation between Nrf2 protein levels and different LN disease states.

Results

There was a significantly positive correlation between serum Nrf2 protein levels, the degree of renal injury, and systemic lupus erythematosus disease activity index (SLEDAI) scores in patients with LN. Nrf2 protein levels were higher in the LN with high-eGFR group than in the healthy control and LN with low-eGFR groups. In follow-up patients in the LN high eGFR group, Nrf2 protein levels decreased significantly after remission of disease activity.

Conclusion

Nrf2 protein expression has a dual role in patients with LN. Nrf2 protein levels not only correlate with disease activity in patients with LN, but also with the degree of kidney injury. Before implementing targeted therapy for Nrf2, evaluating both Nrf2 protein expression and the disease state in patients with LN is necessary to better identify and place each patient in an appropriate patient group.

[Clinical features and VPS33B mutations in a family affected by arthrogryposis, renal dysfunction, and cholestasis syndrome]

Arthrogryposis, renal dysfunction, and cholestasis (ARC) syndrome is an autosomal recessive disorder caused by mutations in the VPS33B or VIPAS39 gene. The aim of this study was to investigate the clinical features and VPS33B gene mutations of an infant with ARC syndrome. A 47-day-old female infant was referred to the hospital with the complaint of jaundiced skin and sclera for 45 days and abnormal liver function for 39 days. The patient had been managed in different hospitals, but the therapeutic effects were unsatisfactory due to undetermined diagnosis. Physical examination showed jaundice of the skin and sclera. Systemic skin was dry with desquamation in the limbs and trunk. There were no positive signs on cardiopulmonary examination. The liver was palpable 2.0 cm under the right subcostal margin. The hips and knees were flexed, and the extension was limited, with low muscular tone in the four limbs. Biochemical analysis demonstrated raised serum total bile acids, bilirubin (predominantly conjugated bilirubin) and transaminases, but the γ-glutamyl transpeptidase level was normal. Routine urine test revealed increased glucose as well as red and white blood cells. On genetic analysis, the infant was proved to be homologous for a VPS33B mutation c.1594C>T(p.R532X). She was definitely diagnosed to have ARC syndrome. Symptomatic and supportive therapy was given, but no improvement was observed, and the infant finally died at 3 months and 29 days of life.

Role of aldosterone in various target organ damage in patients with hypertensive emergency: a cross-sectional study

BACKGROUND

Hypertensive emergency is a critical disease that causes multiple organ injuries. Although the renin-angiotensin-aldosterone system (RAS) is enormously activated in this disorder, whether the RAS contributes to the development of the organ damage has not been fully elucidated. This cross-sectional study was conducted to characterize the association between RAS and the organ damage in patients with hypertensive emergencies.

METHODS

We enrolled 63 patients who visited our medical center with acute severe hypertension and multiple organ damage between 2012 and 2020. Hypertensive target organ damage was evaluated on admission, including severe kidney impairment (eGFR less than 30 mL/min/1.73 m2, SKI), severe retinopathy, concentric left ventricular hypertrophy (c-LVH), thrombotic microangiopathy (TMA), heart failure with reduced ejection fraction (HFrEF) and cerebrovascular disease. Then, whether each organ injury was associated with blood pressure or a plasma aldosterone concentration was analyzed.

RESULTS

Among 63 patients, 31, 37, 43 and 8 cases manifested SKI, severe retinopathy, c-LVH and ischemic stroke, respectively. All populations with the organ injuries except cerebral infarction had higher plasma aldosterone concentrations than the remaining subset but exhibited a variable difference in systolic or diastolic blood pressure. Twenty-two patients had a triad of SKI, severe retinopathy and c-LVH, among whom 5 patients manifested TMA. Furthermore, the number of the damaged organs was correlated with plasma aldosterone levels (Spearman's coefficient = 0.50), with a strong association observed between plasma aldosterone (≥ 250 pg/mL) and 3 or more complications (odds ratio = 9.16 [95%CI: 2.76-30.35]).

CONCLUSION

In patients with hypertensive emergencies, a higher aldosterone level not only contributed to the development of the organ damage but also was associated with the number of damaged organs in each patient.

Short-term course of renal function in accelerated hypertension

Thirty-four patients with primary accelerated hypertension were studied regarding the effect of BP on renal function and the association between fundal grade and renal function before treatment; and the changes in renal function on normalization of BP in 12 patients. Mean arterial pressure was negatively correlated with serum creatinine (r = -0.44, P < 0.02) and there was no significant difference in serum creatinine or in the occurrence of renal failure between patients with grade III (n = 21) and grade IV (n = 13) retinopathy, (P = n.s. and X2 = 0.172 P = n.s. respectively). Twenty-two patients required dialysis at presentation. Serum creatinine rose in 12 other patients on reduction of BP; 7 patients with serum creatinine level < or = 3.2 mg/dL (283 umol/L) at presentation never required dialysis in the 3 months following reduction of BP while those with levels > or = 3.6 mg/dL (319 umol/L) did. In accelerated hypertension, renal function is partly maintained by the blood pressure and dialysis may be required soon after presentation or normalization of BP.

Effects of parathyroid hormone depletion in dogs with induced renal failure

Six parathyroidectomized (PTX) and 6 control dogs had renal mass reduced by 15/16, and were studied for effects of parathyroid hormone depletion on progression of renal failure. All PTX dogs and 4 of 6 control dogs survived until necropsy after 32 weeks. Plasma parathyroid hormone concentration was undetectable in PTX dogs throughout the study, but was greater than normal in control dogs. Serum inorganic phosphate (P) concentration was increased in PTX dogs (6.8 +/- 0.1 mg/dl) and in control dogs (7.5 +/- 0.2), but did not differ significantly (P = 0.254) between groups. Ionized blood calcium values (Ca2+) were significantly (P = 0.014) lower in PTX dogs (1.31 +/- 0.01 mmol/L) than in control dogs (1.36 +/- 0.00 mmol/L), but were more variable in PTX dogs. Values in PTX dogs were not significantly different from those in control dogs for glomerular filtration rate (P = 0.914), plasma creatinine concentration (P = 0.903), and urine protein to creatinine ratio (P = 0.756) determined at intervals during the study. Terminal glucose tolerance and plasma insulin concentrations, P tolerance, and renal P excretion did not differ between groups. Histologic comparison of kidneys removed during reduction of renal mass with kidneys removed at necropsy revealed development of lesions in both groups of dogs, and no protective effect from parathyroidectomy. Mineral analysis of aorta, brain, heart, lungs, and skeletal muscle obtained at necropsy revealed no significant difference between PTX and control groups. Renal cortical calcium concentration was significantly (P < 0.05) greater in kidneys obtained at necropsy then in kidneys obtained during nephrectomy, but PTX did not protect renal cortex from calcium deposition.

[Renal insufficiency with AIDS: ultrasonographic aspects]

Renal pathologic changes in AIDS involve various factors and can also occur in several other forms of renal disease. Renal sonography was prospectively performed in 31 patients with laboratory evidence of AIDS and renal insufficiency. All patients included in this study were without clinical manifestations (group II of the CDC) and without risk factors of AIDS.

AIM

to characterize renal pathologic changes underlying the sonographic findings in these patients. Sonographic evaluation included determination of renal sizes and renal echogenicity according to standard grading system. Sonography showed normal-sized or enlarge-sized kidneys. Enlarged kidneys were generally due to increased thickness rather than length or width; small-sized kidneys were not observed. Grading echogenicity showed: grade 0 in 3 patients, grade I in none, grade II in 11 patients and grade III in 17 patients. In six patients, we found "spotted" echostructural figure due to several hypoechoic and rounded zones. Echogenicity increased with the severity of renal insufficiency. Our study suggests that renal abnormalities are varied and can occur in all stages in the course of the disease. The particular "spotted" figure associated with enlarged size at the expense of thickness of kidneys must draw radiologist's attention to the probability of AIDS lesions. Further studies with large populations must be performed to confirm our observations.

Is the volume of distribution of digoxin reduced in patients with renal dysfunction? Determining digoxin pharmacokinetics by fluorescence polarization immunoassay

STUDY OBJECTIVE

To determine digoxin pharmacokinetics in subjects with different degrees of renal function using fluorescence polarization immunoassay (FPIA), which is associated with less interference from digoxin-like immunoreactive substances (DLIS) than radioimmunoassay.

SETTING

University hospital clinical research center.

PARTICIPANTS

Eighteen subjects (mean age 44 yrs) with different degrees of renal function: group 1, creatinine clearance (Clcr) below 10 ml/minute; group 2, Clcr 10-50 ml/minute; and group 3, Clcr greater than 50 ml/minute (6 patients in each group).

INTERVENTION

Over 5-7 days, 15 serum samples were collected after a single intravenous dose of digoxin 7 or 10 micrograms/kg actual body weight (WT) for serum concentration measurements by FPIA. Two-compartment pharmacokinetic parameters (zero-time intercept of the concentration-time curve of the initial distribution phase [A], zero-time intercept of the concentration-time curve of the terminal elimination phase [B], initial distribution phase constant [alpha], terminal elimination rate constant [beta], volume of distribution in the central compartment [Vc] and at steady state [Vss], total body clearance [Cl], mean residence time [MRT], area under the concentration-time curve [AUC]) were determined using a nonlinear least squares regression program.

MEASUREMENTS AND MAIN RESULTS

No significant differences were found among groups for A, B, alpha, beta, beta-half-life Vc/WT, MRT, AUC, and Cl/WT. Significant differences were observed in Vss/WT (4.8 +/- 1.0, 6.6 +/- 0.5, 6.4 +/- 0.7 L/kg) between group 1 versus group 2 and group 1 versus group 3 (p < 0.01). Measured Clcr was correlated with Cl (r2 = 0.40, p < 0.01), Cl/WT (r2 = 0.29, p < 0.05), Vss (r2 = 0.35, p = 0.01), and Vss/WT (r2 = 0.24, p < 0.05).

CONCLUSION

This study confirmed that Vss is smaller in patients with chronic renal failure (Clcr < 10 ml/min) than those without chronic renal failure. Therefore, previous recommendations that lower digoxin loading doses should be administered in patients with renal failure are applicable to digoxin serum concentration monitoring using FPIA.

[Prevention of lactic acidosis due to metformin intoxication in contrast media nephropathy]

Use of the oral antidiabetic drug metformin may cause lactic acidosis, a rare but life-threatening complication, especially in patients with renal function loss. Since intravenously administered iodide-containing contrast media may cause renal function disturbances precautions should be taken in metformin-treated patients for whom a radiological study with intravenous contrast media is considered. In diabetic patients who use metformin a serum creatinine concentration should be measured prior to the radiological study. If the serum creatinine is within normal limits (< 130 mumol/l), metformin can be continued and the examination performed. If the serum creatinine concentration is increased (> or = 130 mumol/l), metformin should be discontinued and replaced by another antidiabetic drug if necessary. The radiological procedure with intravenous contrast media should be postponed for 48 hours. If such a procedure cannot be postponed, additional measures to prevent lactic acidosis (hydration, monitoring of the renal function) should be taken.

Mesangial cell proliferation is directly enhanced by sera from patients with renal insufficiency

We undertook the present study to determine whether there is a direct effect of sera from patients with renal insufficiency on mesangial cell proliferation. Growth-arrested mesangial cells were incubated with sera from patients with varying degrees of renal insufficiency and then pulsed with [3H]thymidine. Thymidine uptake was progressively greater with more advanced renal failure and was linearly correlated with (creatinine)-1. This data suggests that serum from patients with loss of renal function contains mitogens capable of directly enhancing mesangial cell proliferation.

Fentanyl pharmacokinetics in patients undergoing renal transplantation

STUDY OBJECTIVE

To describe the pharmacokinetics of fentanyl in patients undergoing renal transplantation.

DESIGN

Prospective.

SETTING

A large university teaching hospital.

PATIENTS

Eight patients (mean +/- SD age 35.5 +/- 11.5 yrs, weight 73.4 +/- 24.8 kg) with end-stage renal failure receiving kidneys from a living relative; three patients were never dialyzed, three were receiving peritoneal dialysis, and two were receiving hemodialysis.

INTERVENTIONS

Plasma was sampled before and at intervals up to 8 hours after intravenous injection of fentanyl 25 microg/kg before skin incision.

MEASUREMENTS AND MAIN RESULTS

Mean +/- SD (range) preoperative values were blood urea nitrogen (BUN) 66 +/- 30 (35-111) mg/dl; albumin 3.6 +/- 0.7 (2.6-4.5) g/dl; and triglycerides 414 +/- 352 (156-1270) mg/dl. Elimination half-life was 382 +/- 205 minutes; volume of distribution for the central compartment 0.74 +/- 0.48 L/kg; volume of distribution at steady state (Vd(ss)) 3.1 +/- 2.0 L/kg; total body clearance 7.5 +/- 5.1 ml x kg(-1) x min(-1). A significant inverse relationship between degree of azotemia and fentanyl clearance was found. The two patients with the highest preoperative BUNs had the lowest multiple of clearance and Vd(ss), and were also the only ones to require postoperative mechanical ventilation.

CONCLUSION

Although all patients received a kidney that functioned well after revascularization, the large intersubject variability in fentanyl kinetics may, in part, reflect their heterogeneity in dialysis status and renal failure-induced abnormalities. Marked decreases in fentanyl clearance do occur in these patients, appear to be related to very high BUN concentrations, and can lead to prolonged postoperative ventilatory depression.

Evolution of the parathyroid hormone (PTH) assay--importance of circulating PTH immunoheterogeneity and of its regulation

Most of what we know on PTH bioactivity has been associated with the first 34 amino acids of the PTH structure acting on the type I PTH/PTHrP receptor, leaving little place to the carboxyl-terminal structure. This reality has dictated the evolution of the PTH assay. The first generation of PTH assays has permitted the description of circulating PTH immunoreactivity and of its acute regulation by calcium concentration. Most assays reacted with the dominant forms of circulating PTH, PTH fragments devoid of bioactivity. This was believed to limit their clinical performance, particularly in the diagnosis of hypercalcemic disorders and the evaluation of secondary hyperparathyroidism and/or bone diseases associated with chronic renal failure. This brought up the development of a 2nd generation of PTH assays, the Intact (I) PTH assay. These assays were initially demonstrated to react only with hPTH(1-84), the bioactive form of the hormone. They greatly improved the differential diagnosis of hypercalcemic disorders, facilitated studies of parathyroid function in renal failure patients but were still limited in their capacity to dissociate the various bone diseases associated with chronic renal failure. Eventually, it was demonstrated that these assays, which used 13-34 epitopes, reacted with large C-PTH fragments having a partially preserved amino-terminal (N) structure, also called non-(1-84) PTH. These fragments accounted for up to 50% of I-PTH immunoreactivity in renal failure patients. hPTH(7-84), a surrogate of non-(1-84) PTH fragments, was demonstrated to cause hypocalcemia and to antagonize hPTH(1-34) and hPTH(1-84) calcemic effect in vivo and to inhibit bone resorption in vitro via a C-PTH receptor, different from the type I PTH/PTHrP receptor. This suggested a dual control of calcium concentration via N- and C-PTH molecular forms. This also explained why the ratio of C-PTH fragments/I-PTH was so well regulated both acutely and chronically in various experimental conditions. The fact that I-PTH assays detected circulating PTH molecular forms with biological effects opposite to those of hPTH(1-84) was believed to explain their limitations, particularly in renal failure, and prompted the evolution of a third generation of PTH assays. The last is based on a 1-4 epitope to reveal PTH(1-84) and not hPTH(7-84). It also permits an indirect evaluation of non-(1-84) PTH fragments by subtracting a 3rd generation PTH value from a 2nd generation PTH value and the calculation of a PTH(1-84)/non-(1-84) PTH ratio. The combination of a third generation PTH value with the PTH(1-84)/non-(1-84) PTH ratio value has in some studies improved the differential diagnosis of bone diseases associated with renal failure. But more studies are required to see whether PTH(1-84)/PTH fragment ratios will improve the clinical performance of PTH concentrations used alone.

[Antimicrobial agents in pediatric cancer patients with hepatic or renal impairment]

Antimicrobial agents are among the most frequently prescribed therapeutics in the supportive care of children and adolescents with cancer or following hematopoietic stem cell transplantation. Most of these agents are cleared from the body by elimination of unchanged drug by the kidney and/or metabolism by the liver. Impaired renal and hepatic function may have profound effects on the pharmacokinetics and pharmacodynamics of antimicrobial agents, necessitating modification of the dosage regimen in order to avoid toxicity through accumulation of the parent and/or its metabolites. Key to minimize such toxicities is a thorough understanding of the antimicrobial drug armamentarium and a careful evaluation of benefits and risks of antimicrobial interventions. This article reviews the mechanisms of renal and hepatic drug clearance in the normal state and in the state of functional impairment, their implications for antimicrobial therapy and dosage recommendations for pediatric cancer patients with impaired renal or hepatic function.

[Renal failure in patients with cirrhosis and ascites: incidence, etiology and predictive factors]

BACKGROUND

renal insufficiency (RI) is a frequent complication in patients with cirrhosis and ascites.

OBJECTIVE

to assess the incidence, causes, predictive factors and prognosis of RI in cirrhotic patients with ascites.

PATIENT AND METHODS

descriptive study of cases and controls. Clinical histories of 162 admissions in 103 patients during 3 years were reviewed. It was considered RI when there was an increase of creatininemia > 1.5 mg/dl. The predictive factors, clinical features, and mortality of the patients with and without RI were compared.

RESULTS

a diagnosis of RI was made in 35 cases (21.6%). Hospital mortality rate was 18.5%: with RI 57.1%, controls 7.8% (p<0.01).

ETIOLOGY

reversible prerrenal failure (54.3%), SHR 1 (14.2%) and 2 (5.7%), septic shock by spontaneous bacterial peritonitis (SBP) (11.4%), NTA (8.5%). The patients with and without RI had a Child-Pügh score average (+/-DS): 12.8 (1.8) and 11.4 (1.9) (p=0.0002) respectively. The patients with RI had higher values of total bilirubin, AST, ALT, white blood cells, time prothrombin, and minors values of serum sodium, Hto, Hb, protein, albumin and cholinesterase that controls (p<0.05). The clinical variables associated with RI included infections (OR 1.4), SBP (OR 4) and hepatic encephalopathy (OR 2.4). In the multivariate analysis, the independent predictive factors for RI were hyponatremia, bilirubinemia greater to 10 mg/dl and SPB.

CONCLUSION

in cirrhotic patients RI have high mortality. The most frequent cause was reversible prerrenal failure. The risk of RI was increased significantly in patients with hyponatremia, marked hyperbilirubinemia and SPB.

[Clinical and laboratory features and prognostic implications in myeloma with and without renal impairment]

Presenting clinical and laboratory features, prognostic implications and survival in 124 multiple myeloma patients were reviewed in a retrospective study based on hospital records. The median age was 65 years. Out of all patients, 2.42% were younger than 40 years and 62.9% were 60 years and older. The main presenting clinical features were bone pain (70.16%), fatigue (31.45%), recurrent infections (9.68%) and weight loss (0.3%). Renal failure was present in 35.48% of patients. The higher means of ionised calcium, uric acid, erythrocyte sedimentation rate, M protein were correlated with the higher mean of serum creatinine. The acturial survival of myeloma patients without renal failure at 1 and 2 years was 95.08% and 89.23% respectively, while acturial survival of myeloma patients with renal failure at 1 and 2 years was 82.5% and 73.35% respectively (p<0.01). One-year survival in myeloma patients maintained on chronic hemodialysis was 68.75% while it is reported as 90.91% for myeloma patients not on dialysis (p<0.006).

[Effect of angiotensin-converting enzyme inhibitors on serum levels of erythropoietin in patients on peritoneal dialysis]

OBJECTIVE

To assess the effect of angiotensin-converting enzyme inhibitors (ACEI) on the serum level of erythropoietin (EPO) in patients receiving peritoneal dialysis and explore the possible mechanism.

METHODS

Thirty-six patients receiving peritoneal dialysis were enrolled in this study, among whom 26 received EPO treatment and the other 10 did not. The 2 groups were randomly subdivided into experimental group and control group with equal cases in each, the former with ACEI prescription to control blood pressure while the latter with calcium channel blocker or alpha-receptor blocker. Serum levels of EPO and hemoglobin (Hb) in all the patients were determined before and 6 months after their respective therapies.

RESULTS

The serum levels of EPO and Hb decreased significantly after therapy in the experimental group (P<0.05), obviously lower than those in the control group (P<0.05).

CONCLUSION

ACEI may decrease the serum EPO and Hb levels in patients receiving peritoneal dialysis.

[Comparison of methods for evaluating renal function (Data of Kaunas University of Medicine Hospital in 2006)]

Cockcroft-Gault formula and Modification of Diet in Renal Disease (MDRD) equation are widely used as indirect estimates of renal function. The precision and reliability of these formulas regarding kidney function are still discussed. The aim of our study was to evaluate glomerular filtration rate by different methods and compare the results. Data on patients in whom renal function was evaluated at the Clinic of Nephrology of Kaunas University of Medicine Hospital in 2006 are presented in this article. Glomerular filtration rate was assessed based on 24-hour endogenous creatinine clearance and calculated using three formulas: Cockcroft-Gault, abbreviated MDRD, and complete MDRD. Blood serum creatinine level was measured by the standardized Jaffe assay. Glomerular filtration rate was examined in 125 patients. Their mean age was 58.07+/-18.962 years. The mean endogenous creatinine clearance was 31.1287+/-31.14 783 mL/min. The mean glomerular filtration rate calculated by Cockcroft-Gault formula was 34.1220+/-29.02 967 mL/min, by abbreviated MDRD formula was 29.8212+/-25.83 866 mL/min/1.73 m2, and by complete MDRD formula was 28.6884+/-24.99 353 mL/min/1.73 m2. There was no statistically significant difference in mean glomerular filtration rates estimated using all methods in the evaluation of kidney function. When the reliability of formulas was analyzed depending on each stage of chronic kidney disease, it was found that Cockcroft-Gault and MDRD formulas, in contrast to endogenous creatinine clearance, did not precisely reflect kidney function in stages 1 and 2 of chronic kidney disease. Estimates by Cockcroft-Gault and MDRD formulas correctly showed decreased kidney function in stages 3 and 4 of chronic kidney disease. Formulas were not reliable, in contrast to endogenous creatinine clearance, when patients were in end-stage chronic kidney disease. CONCLUSIONS. Cockcroft-Gault and MDRD formulas are best for the evaluation of moderate degree of renal insufficiency, and in early stage of chronic kidney disease, underestimation of glomerular filtration rate is possible by using formulas. Estimates of glomerular filtration rate based on formulas are higher as compared to endogenous creatinine clearance measurements in end-stage chronic kidney disease.

[Impaired renal function: be aware of exogenous factors]

BACKGROUND

Renal function is currently estimated using the Modification of Diet in Renal Disease (MDRD) formula, which is partly based on the serum creatinine level. Patients with impaired renal function are referred to nephrologists in accordance with the Dutch national transmural agreement for 'Chronic renal impairment'.

CASE DESCRIPTION

A 54-year-old woman without significant history was referred to analyse a coincidentally found decline in the estimated glomerular filtration rate (eGFR). The patient had no complaints and used no medication except creatine supplements. Additional diagnostic testing showed no abnormalities. After cessation of creatine supplementation, the calculated renal function normalized.

CONCLUSION

Serum creatinine is a reflection of muscle mass. The use of creatine-containing dietary supplements, such as creatine ethyl ester, can influence serum creatinine levels and therefore the eGFR as calculated with the MDRD formula. The use of supplements deserves attention when taking the history.