Dry eye rate and its relationship with disease stage in patients with primary hypertension: a cross-sectional study in Vietnam.

AIM: To determine the dry eye (DE) rate and its relationship with disease stage in patients with primary hypertension. METHODS: A cross-sectional study included 432 patients with primary hypertension (with an equal number of patients in each group: 144 in stage I, II, and III hypertension) and 144 healthy subjects as a control group. The Ocular Surface Disease Index (OSDI) and Schirmer I test without anesthetics were conducted on all 576 subjects. Subjects with OSDI scores <13 and Schirmer I values equal to or under 10 mm were diagnosed with DE. RESULTS: The ratio of DE in hypertension patients was higher than in the control group (41.7% versus 18.8%; P<0.001). The proportion of patients with DE increased gradually according to the hypertension stage: 27.1% in stage I, 40.3% in stage II, and 57.6% in stage III, P<0.001. Age, duration of hypertension, plasma urea, creatinine, and high-sensitivity C-reactive protein (CRP-hs) levels in hypertension patients with DE were higher than those without DE, P<0.001. Advanced age, a long duration of hypertension, diabetes mellitus, elevated plasma creatinine, and CRP-hs levels were independent factors associated with DE in primary hypertension patients, P<0.001. CONCLUSION: DE is a common disorder associated with advanced age, a long duration of hypertension, diabetes mellitus, elevated plasma CRP-hs, and creatinine levels in patients with primary hypertension.

Transcutaneous measurement of renal function in two rodent models of obstructive nephropathy.

OBJECTIVE: Glomerular filtration rate (GFR) is a key indicator of renal function. In both clinical practice and pre-clinical research, serum levels of endogenous filtration markers, such as creatinine, are often used to estimate GFR. However, these markers often do not reflect minor changes in renal function. In this study, we therefore set out to evaluate the applicability of transcutaneous GFR (tGFR) measurements to monitor the changes in renal function, as compared to plasma creatinine (pCreatinine), in two models of obstructive nephropathy, namely unilateral ureteral obstruction (UUO) or bilateral ureteral obstruction followed by release (BUO-R) in male Wistar rats. RESULTS: UUO animals showed a significant reduction in tGFR compared to baseline; whereas pCreatinine levels were not significantly changed. In BUO animals, tGFR drops 24 h post BUO and remains lower upon release of the obstruction until day 11. Concomitantly, pCreatinine levels were also increased 24 h after obstruction and 24 h post release, however after 4 days, pCreatinine returned to baseline levels. In conclusion, this study revealed that the tGFR method is superior at detecting minor changes in renal function as compared to pCreatinine measurements.

Mesenteric elasticity assessed by shear wave elastography and its relationship with peritoneal function in peritoneal dialysis patients.

Background: We evaluated the mesenteric elasticity in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) using shear wave elastography (SWE) and investigated its relationships with peritoneal function. Methods: Patients were recruited in our peritoneal dialysis (PD) centre between 15 July 2019 and 31 December 2021 and followed up to 31 March 2022. Twelve chronic kidney disease (CKD) patients and nineteen healthy people were included as controls. Correlation, linear regression and Cox regression analyses were applied. Results: Of the 218 PD patients, 104 (47.8%) were male. Their mean age was 48.0 ± 13.2 years and the median PD duration was 59.0 months [interquartile range (IQR) 17.0-105]. The median mesenteric SWE value was 8.15 kPa (IQR 5.20-16.1). The mesenteric SWE values of patients with a PD duration of <3 months [5.20 kPa (IQR 3.10-7.60)] were not significantly different from those of CKD patients [4.35 kPa (IQR 2.63-5.20), P = .17] and healthy controls [3.60 kPa (IQR 2.90-5.10), P = .13] but were lower than those of patients with a PD duration of 3 months-5 years [6.40 kPa (IQR 4.10-10.5), P < .001], 5-10 years [11.9 kPa (IQR 7.40-18.2), P < .001] and >10 years [19.3 kPa (IQR 11.7-27.3), P < .001]. Longer PD duration (ß = 0.58, P < .001), high effluent interleukin-6 (ß = 0.61, P = .001) and low effluent cancer antigen 125 (ß = -0.34, P = .03) were independently associated with low mesenteric elasticity. The mesenteric SWE value was independently correlated with the dialysate:plasma creatinine ratio (ß = 0.39, P = .01) and negatively correlated with the total daily fluid volume removed (ß = -0.17, P = .03). High mesenteric SWE values were an independent risk factor for death-censored technique failure [adjusted hazard ratio 4.14 (95% confidence interval 1.25-13.7), P = .02). Conclusions: SWE could be used to non-invasively characterize peritoneal textural changes, which were closely associated with changes in peritoneal function.

The Urinary Level of Injury Biomarkers Is Not Univocally Reflective of the Extent of Toxic Renal Tubular Injury in Rats.

Nephrotoxicity is a major cause of intrinsic acute kidney injury (AKI). Because renal tissue damage may occur independently of a reduction in glomerular filtration rate and of elevations in plasma creatinine concentration, so-called injury biomarkers have been proposed to form part of diagnostic criteria as reflective of tubular damage independently of renal function status. We studied whether the urinary level of NGAL, KIM-1, GM2AP, t-gelsolin, and REGIIIb informed on the extent of tubular damage in rat models of nephrotoxicity, regardless of the etiology, moment of observation, and underlying pathophysiology. At a time of overt AKI, urinary biomarkers were measured by Western blot or ELISA, and tubular necrosis was scored from histological specimens stained with hematoxylin and eosin. Correlation and regression studies revealed that only weak relations existed between biomarkers and tubular damage. Due to high interindividual variability in the extent of damage for any given biomarker level, urinary injury biomarkers did not necessarily reflect the extent of the underlying tissue injury in individual rats. We contended, in this work, that further pathophysiological contextualization is necessary to understand the diagnostic significance of injury biomarkers before they can be used for renal tubular damage severity stratification in the context of nephrotoxic and, in general, intrinsic AKI.

Dehydration before Major Urological Surgery and the Perioperative Pattern of Plasma Creatinine: A Prospective Cohort Series.

Preoperative dehydration is usually found in 30-50% of surgical patients, but the incidence is unknown in the urologic population. We determined the prevalence of preoperative dehydration in major elective urological surgery and studied its association with postoperative outcome, with special attention to plasma creatinine changes. We recruited 187 patients scheduled for major abdominal urological surgery to participate in a single-center study that used the fluid retention index (FRI), which is a composite index of four urinary biomarkers that correlate with renal water conservation, to assess the presence of dehydration. Secondary outcomes were postoperative nausea and vomiting (PONV), return of gastrointestinal function, in-hospital complications, quality of recovery, and plasma creatinine. The proportion of dehydrated patients at surgery was 20.4%. Dehydration did not correlate with quality of recovery, PONV, or other complications, but dehydrated patients showed later defecation (p = 0.02) and significant elevations of plasma creatinine after surgery. The elevations were also greater when plasma creatinine had increased rather than decreased during the 24 h prior to surgery (p < 0.001). Overall, the increase in plasma creatinine at 6 h after surgery correlated well with elevations on postoperative days one and two. In conclusion, we found preoperative dehydration in one-fifth of the patients. Dehydration was associated with delayed defecation and elevated postoperative plasma creatinine. The preoperative plasma creatinine pattern could independently forecast more pronounced increases during the early postoperative period.

Rapid Quantification of Plasma Creatinine Using a Novel Kinetic Enzymatic Assay.

BACKGROUND: Enzymatic assays are among the most common diagnostic tests performed in the clinical laboratory. Enzymatic substrate analysis is most commonly measured using endpoint methods; however, modulating the reaction kinetics allows fine control of the reaction rate, which can be adjusted based on specific monitoring technologies. METHODS: We developed and optimized an enzymatic method for measurement of creatinine in plasma, using commonly paired enzymes of creatininase (Crtnnase), creatinase (Crtase), sarcosine oxidase (SOX), ascorbate oxidase (AOX), and horseradish peroxidase (HRP). The novel aspect of the assay is that it is fast and uses SOX as the limiting enzyme. The assay performance was assessed with respect to precision, accuracy, and interferences. RESULTS: The intrarun %CV (n = 12) was approximately 5% for each concentration tested, with biases ranging from -3 to -9%. The interrun %CV (n = 39) ranged from 5 to 8%, with biases ranging from -2 to -6%. During the accuracy assessment (n = 127), only 4 samples did not meet the minimum acceptability criteria. Minimal interference was observed, except at low creatinine concentrations with elevated creatine. CONCLUSION: Our novel and versatile enzymatic assay to measure plasma creatinine using kinetic analysis with SOX as the limiting enzyme is rapid (<2 mins), sensitive, and specific and demonstrates excellent concordance with the laboratory standard. We anticipate this rapid kinetic assay to be compatible with emerging technologies in the field of portable diagnostic devices, such as the usage of silicon photonics to monitor biochemical reactions.

Plasma creatinine medians from patients partitioned by gender and age used as a tool for assessment of analytical stability at different concentrations.

Background Monthly medians of patient results are useful in assessment of analytical quality in medical laboratories. Separate medians by gender makes it possible to generate two independent estimates of contemporaneous errors. However, for plasma creatinine, reference intervals (RIs) are different by gender and also higher over 70 years of age. Methods Daily, weekly and monthly patient medians were calculated from the raw data of plasma creatinine concentrations for males between 18 and 70 years, males >70 years, females between 18 and 70 years and females >70 years. Results The medians of the four groups were all closely associated, with similar patterns. The mean of percentage bias from each group defined the best estimate of bias. The maximum half-range (%) of the bias evaluations provided an estimate of the uncertainty comparable to the analytical performance specifications: thus, bias estimates could be classified as optimum, desirable or minimum quality. Conclusions Medians by gender and age are useful in assessment of analytical stability for plasma creatinine concentration ranging from 60 to 90 µmol/L. The daily medians are valuable in rapid detection of large systematic errors, the weekly medians in detecting minor systematic errors and monthly medians in assessment of long-term analytical stability.

Monitoring disease progression with plasma creatinine in amyotrophic lateral sclerosis clinical trials.

OBJECTIVES: Plasma creatinine is a predictor of survival in amyotrophic lateral sclerosis (ALS). It remains, however, to be established whether it can monitor disease progression and serve as surrogate endpoint in clinical trials. METHODS: We used clinical trial data from three cohorts of clinical trial participants in the LITRA, EMPOWER and PROACT studies. Longitudinal associations between functional decline, muscle strength and survival with plasma creatinine were assessed. Results were translated to trial design in terms of sample size and power. RESULTS: A total of 13 564 measurements were obtained for 1241 patients. The variability between patients in rate of decline was lower in plasma creatinine than in ALS functional rating scale-Revised (ALSFRS-R; p<0.001). The average rate of decline was faster in the ALSFRS-R, with less between-patient variability at baseline (p<0.001). Plasma creatinine had strong longitudinal correlations with the ALSFRS-R (0.43 (0.39-0.46), p<0.001), muscle strength (0.55 (0.51-0.58), p<0.001) and overall mortality (HR 0.88 (0.86-0.91, p<0.001)). Using plasma creatinine as outcome could reduce the sample size in trials by 21.5% at 18 months. For trials up to 10 months, the ALSFRS-R required a lower sample size. CONCLUSIONS: Plasma creatinine is an inexpensive and easily accessible biomarker that exhibits less variability between patients with ALS over time and is predictive for the patient's functional status, muscle strength and mortality risk. Plasma creatinine may, therefore, increase the power to detect treatment effects and could be incorporated in future ALS clinical trials as potential surrogate outcome.

Risk factors for encapsulating peritoneal sclerosis: Analysis of a 36-year experience in a University Hospital.

AIM: Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication that occurs in peritoneal dialysis (PD) therapy. The present study aimed to identify the risk factors, especially peritonitis and biocompatible PD fluid. METHODS: The study included 703 patients who received PD between January 1980 and March 2015 at two centres. The patients were divided into two groups: those who had developed EPS (EPS group: n = 44) and those who had no documentary evidence of EPS (non-EPS group: n = 659). The independent risks of EPS were determined by univariate and multivariate logistic models. RESULTS: Encapsulating peritoneal sclerosis occurred in 44/703 (6.3%) patients between January 1980 and March 2015. In multivariate logistic models of risk factors correlated with EPS, dialysate to plasma creatinine ratio (D/P Cr) by peritoneal equilibration test (PET) and history of peritonitis were risk factors for EPS development (P < 0.01, respectively) in addition to PD duration. Especially, total duration of peritonitis, defined by period between onset and resolution of peritonitis, was an important risk factor for EPS development in patients with a history of peritonitis. Receiver operating characteristic (ROC) curve analysis revealed that cut-off point for EPS development was 36 days. Moreover, biocompatible PD fluid contributed to decreased EPS development. CONCLUSION: Both the longer duration of peritonitis and higher D/P Cr, as well as the longer PD duration, were risk factors for EPS development. Furthermore, use of biocompatible PD fluid contributed to the decrease in EPS development.

Falsely Elevated Plasma Creatinine Due to an Immunoglobulin M Paraprotein.

The most common method for measuring plasma creatinine is based on its reaction with picric acid. However, enzymatic methods are becoming more popular due to improved specificity. We present a case of falsely elevated plasma creatinine values obtained by an enzymatic method that turned out to be due to a monoclonal immunoglobulin M (IgM) paraprotein. A 63-year-old woman evaluated for lung transplantation had falsely increased plasma creatinine levels (1.54-1.71mg/dL; corresponding to estimated glomerular filtration rates of 32-36 mL/min/1.73m2) as measured by the Roche Creatinine plus enzymatic assay when compared with the picric acid-based procedure and several other enzymatic methods, which gave plasma creatinine values of 0.7 to 0.8mg/dL. Serum protein electrophoresis revealed an IgM κ light chain paraprotein. Removal of high-molecular-weight (>30kDa) proteins by ultrafiltration reduced the patient's plasma creatinine level by the Roche enzymatic method to 0.7mg/dL. Addition of the patient's immunoglobulin fraction to plasma from other patients with normal plasma creatinine levels resulted in values that were increased by 0.58 to 0.62mg/dL. Furthermore, removal of non-IgM immunoglobulins with protein G-coupled beads did not eliminate the interference from the patient's plasma. Taken together, these studies demonstrate that falsely elevated plasma creatinine values by the Roche enzymatic method can be due to an IgM paraprotein.

Basal elevated serum calcium phosphate product as an independent risk factor for mortality in patients with fractures of the proximal femur-A 20 year observation study.

INTRODUCTION: Fractures of the proximal femur are a significant cause of mortality and morbidity in the elderly population. Yet predictive marker of unfavourable prognosis are still lacking. Calcium phosphate product is a marker of osteo-renal dysregulation. This study investigated the role of serum calcium phosphate product (SCPP) levels as a prognostic parameter for outcome in those patients. PATIENTS AND METHODS: A total of 3577 consecutive patients with diagnosed fractures of the proximal femur were included in our study (72.5% females). SCPP was divided into tertiles: <1.92mmol(2)/l(2), 1.93-2.38mmol(2)/l(2) and >2.39mmol(2)/l(2). Data collection was performed prospectively and statistical evaluation was performed retrospectively. RESULTS: Mean follow up in our study group was 11.0±0.3 months. The mean age of our study group was 79.0 years (SEM ±14 years). To facilitate analysis, patients were divided in two groups: ≤84 years (64.4%) and ≥85 years (35.6%), and mortality <12 months was 12.4% (n=445). In our study population higher SCPP levels ad admission were associated with a markedly elevated mortality. In a multivariate logistic regression model adjusted for age and sex, plasma creatinine and haemoglobin at admission caused a 1.3 (CI: 1.01-1.6) for SCPP 1.93-2.38mmol(2)/l(2), and a 1.6 (CI: 1.2-2.0) for SPP >2.39mmol(2)/l(2) fold increase in overall mortality compared to patients with baseline SCPP levels (<1.92mmol(2)/l(2)) as reference category. CONCLUSION: Those findings in our study population with 3577 patients over a period of 20 years proved to be, that serum Ca levels may be a good predictor for mortality in patients with fracture of the proximal femur. Further studies are required to evaluate whether these high risk patients might benefit from specific therapeutic measurements. This prognostic factor may help to increase the outcome of elderly patients with a fracture of the proximal femur.

[ADVANCED AND SENILE AGE FOR THE FIRST DAYS AFTER X-RAY ENDOVASCULAR INTERVENTIONS].

Research of the glomerular filtration rate at the patients of advanced and senile age who underwent X ray endovascular intervention is conducted. Patients of age groups are examined: 34-59 years (49,7±7,8 years) - 35 people (group of control), 60-74 years (65,5±4,1) - 38 people and 75-82 years (77,5±2,5) - 12 people. Methods of screening calculation of the glomerular filtration rate are compared. The conclusion that regardless of techniques of definition of GFR and its initial level, the orientation of change of this parameter is characterized by its decrease at all patients after performance of coronary angiography, but more at patients of senile age group is drawn. It is expedient to use Cockcroft-Gault's formula for screening determination of speed of the glomerular filtration rate at people of advanced and senile age, in particular in patients with ischemic heart disease when carrying out X-ray endovascular interventions.

Basal haemoglobin levels as prognostic factor for early death in elderly patients with a hip fracture--A twenty year observation study.

INTRODUCTION: Hip fractures are a significant cause of mortality and morbidity in the elderly. This study investigated the relationship between initial haemoglobin (Hb) levels and a prognostic parameter for outcome in those patients. PATIENTS AND METHODS: A total of 3595 consecutive patients with diagnosed hip fractures were included in our study (72.2% females). Anaemia was defined according to WHO criteria, with according subgroups mild, moderate and severe anaemia. Data collection was performed prospectively and statistical evaluation was performed retrospectively. RESULTS: Mean follow up in our study group was 11.2 ± 0.3 months. The mean age of our study group was 78.5 years (SEM ± 0.2 years). To facilitate analysis, patients were divided in two groups: ≤ 84 years (60.1%) and ≥ 85 years (39.9%). Mortality <12 months was 12.2% (n = 439). In our study population lower Hb levels ad admission were associated with a markedly elevated short-term mortality. In a multivariate logistic regression model adjusted for age and sex, mild anaemia at admission caused a 1.5 (CI: 1.1-1.9), moderate anaemia a 2.6 (95 CI: 2.0-3.4), and severe anaemia a 3.6 (CI: 1.8-6.9) fold increase in three months mortality compared to patients without anaemia. Total lymphocyte count (1.2 ± 0) did not show any differences between the subgroups. CONCLUSION: Those findings in our study population with 3595 patients over a period of twenty years have proven that initial Hb levels are a useful and cost effective parameter to predict mortality in elderly patients with a hip fracture. This prognostic factor may help to increase the outcome of elderly patients with a hip fracture.

Evaluation of renal function in patients with cirrhosis: where are we now?

In the clinical context of the patients with liver cirrhosis, accurate evaluation of the renal function is potentially crucial. Indeed, it can lead to early diagnosis of both acute kidney injury and chronic kidney disease and to reliable characterization of the renal status of the patient before performing a liver transplantation. Despite some limitations, the assay of serum creatinine (SCr) is universally used to estimate glomerular filtration rate (GFR) because of its wide availability, its simplicity and because it is inexpensive. Nevertheless, several reports show that the value of this assay to estimate GFR is strongly challenged in cirrhotic patients, especially in patients with liver failure and/or severely impaired renal function. This has led to seek new alternatives to estimate more reliably the GFR in these patients. Although the reference methods, based on the utilization of exogenous markers, allow measuring GFR and thereby constitute the "gold standard" to evaluate renal function, they are not feasible in routine clinical practice. Several studies have shown that a cystatin C (CysC) based formula perform better than the SCr-based estimates in cirrhotic patients and the estimation of GFR by these formulas could therefore lead to optimize the management of the patients. A new estimate based on CysC has been recently developed using a large number of patients and the first results regarding the evaluation of its performance are promising, making this new formula the best candidate for a reference estimate of the renal function in cirrhotic patients.

Correlation of 2 hours and 24 hours creatinine clearance in renal donors after unilateral nephrectomy.

BACKGROUND: The kidney performs numerous specialised functions in an effort to maintain constancy of the internal composition of body fluids. AIM: This study was done to ascertain the feasibility of estimating creatinine clearance as an outpatient procedure over a 2 hours period instead of doing the study over a 24 hours period. MATERIAL AND METHODS: Eighteen renal donors, Twelve females and Six males, who were closely related to recipients, were chosen. This study was done on renal donors who attended the Nephrology Department of Rajiv Gandhi Government General Hospital, Madras Medical College, Chennai-03 India. To estimate creatinine clearance in 24 hours urine, 24 hours urine sample was collected from 9 am on the first day to 9 am on the next day, after first emptying the bladder. Then, creatinine clearance was calculated by using standard formula, CC=UV/ Pt X 1.73m(2)/BSA of the individual. RESULTS: There was no significant differences in mean creatinine clearance values by collecting 2 hours and 24 hours urine samples from renal donors in different stages of post nephrectomy period. It has been shown that 2 hours collection of urine sample is as good as 24 hours urine sample for estimating creatinine clearance. CONCLUSION: Hence it was proved that measurement of creatinine clearance could be done as an outpatient procedure, as the patient needed only 2 hours of hospital stay.

Involvement of hydrogen sulfide and homocysteine transsulfuration pathway in the progression of kidney fibrosis after ureteral obstruction.

Hydrogen sulfide (H2S) produced by cystathionine ß-synthase (CBS) and cystathionine γ-lyase (CSE) in the transsulfuration pathway of homocysteine plays a number of pathophysiological roles. Hyperhomocysteinemia is involved in kidney fibrosis. However, the role of H2S in kidney fibrosis remains to be defined. Here, we investigated the role of H2S and its acting mechanism in unilateral ureteral obstruction (UO)-induced kidney fibrosis in mice. UO decreased expressions of CBS and CSE in the kidney with decrease of H2S concentration. Treatment with sodium hydrogen sulfide (NaHS, a H2S producer) during UO reduced UO-induced oxidative stress with preservations of catalase, copper-zinc superoxide dismutase (CuZnSOD), and manganese superoxide dismutase (MnSOD) expression, and glutathione level. In addition, NaHS mitigated decreases of CBS and CSE expressions, and H2S concentration in the kidney. NaHS treatment attenuated UO-induced increases in levels of TGF-ß1, activated Smad3, and activated NF-κB. This study provided the first evidence of involvement of the transsulfuration pathway and H2S in UO-induced kidney fibrosis, suggesting that H2S and its transsulfuration pathway may be a potential target for development of therapeutics for fibrosis-related diseases.

Impacto de la medición de creatinina en la estimación de la velocidad de filtración glomerular / Impact of creatinine measurement on glomerular filtration rate estimation / Impacto da medição de creatinina na estimativa da velocidade de filtração glomerular

Con el objeto de detectar precozmente la enfermedad renal crónica, muchas sociedades científicas han recomendado incorporar a los informes de laboratorio la velocidad de filtración glomerular (VFG) estimada por fórmulas asociadas a creatinina plasmática (Cr) como marcador de función renal. Frente a la variedad de metodologías disponibles en Argentina, los bioquímicos se encuentran frente al dilema de la elección del método a utilizar para cuantificar Cr. El objetivo de este trabajo es analizar si la VFG estimada por fórmulas a partir de Cr dosadas por diferentes métodos son comparables. Si bien no se observaron diferencias estadísticamente significativas entre las Cr cuantificadas por los métodos Jaffé cinético (JC), Jaffé cinético con compensación (JCCC) y enzimático (ENZ), no se obtuvo una correlación adecuada entre los mismos. Se observó que el método de Jaffé cinético sin compensación arrojó resultados de creatinina sérica, que al trasladarse a ecuaciones que determinan la VFG, dejaron un margen de error inaceptable (circunstancia que no se obser­vó de igual forma en el JCCC). Se concluye que la VFG estimada por fórmulas a partir de Cr dosadas por los métodos JC y JCCC, tomando como referencia el método enzimático, no son comparables.

In order to do early detection of chronic renal disease, many scientific societies have recommended to report a GFR estimate usinga prediction equation associated with serum creatinine measurement, as a marker of renal function. Faced with the wide variety of available creatinine measurement, as a marker of renal function. Faced with the wide variety of available creatinine methodologies in this country, professionals have a dilemma: the choice of which method must be used to quantify creatinine. The purpose of this study is to analyze whether the estimates of GFR usingcreatinine measures by different methods are comparable. Although no statistically significant differences between Cr quantified by Kinetic Jaffe method (JC), compensated kinetic Jaffe (JCCC) and enzymatic (ENZ) were observed, no good correlation was obtained between them. It was observed that the kinetic Jaffe method without compensation showed results that, beingincorporated in equations that determine the GFR, left an unacceptable margin of error (a circumstance that was not observed in the JCCC). Conclusion: GFRestimated with formulas usingcreatinine measured by JC and JCCC compared to ENZ are not comparable.

Visando detectar precocemente a doençã renal crônica, muitas sociedades científicas têm recomendado incorporar aos relatórios de laboratório a velocidade de filtração glomerular (VFG) estimada por fórmulas associadas a creatinina plasmática (Cr) como marcador de função renal. Frente à variedade de metodologias disponíveis na Argentina, os bioquímicos se encontram frente ao dilema da seleção do método a utilizar para quantificar Cr. O objetivo deste trabalho é analisar se a VFGestimada por fórmulas a partir de Cr dosadas por diferentes métodos são comparáveis. Embora não se observassem diferenças estatisticamente significativas entre as Cr quantificadas pelos métodos Jaffé cinético (JC), Jaffé cinético com compensação (JCCC) e enzimático (ENZ), não foi obtida uma correlação adequada entre os mesmos. Observouse que o método de Jaffe cinético sem compensação deuresultados de creatinina sérica, que ao se trasladarem para equações que determinam a VFG, deixaram uma margem de erro inaceitável (circunstância que não se observoude igual forma no JCCC). Conclusão: a VFGestimada por fórmulas a partir de Cr dosadas pelos métodos JC e JCCC, tomando como referência o método enzimático, não são comparáveis.

Impacto de la medición de creatinina en la estimación de la velocidad de filtración glomerular / Impact of creatinine measurement on glomerular filtration rate estimation / Impacto da mediþÒo de creatinina na estimativa da velocidade de filtraþÒo glomerular

Con el objeto de detectar precozmente la enfermedad renal crónica, muchas sociedades científicas han recomendado incorporar a los informes de laboratorio la velocidad de filtración glomerular (VFG) estimada por fórmulas asociadas a creatinina plasmática (Cr) como marcador de función renal. Frente a la variedad de metodologías disponibles en Argentina, los bioquímicos se encuentran frente al dilema de la elección del método a utilizar para cuantificar Cr. El objetivo de este trabajo es analizar si la VFG estimada por fórmulas a partir de Cr dosadas por diferentes métodos son comparables. Si bien no se observaron diferencias estadísticamente significativas entre las Cr cuantificadas por los métodos Jaffé cinético (JC), Jaffé cinético con compensación (JCCC) y enzimático (ENZ), no se obtuvo una correlación adecuada entre los mismos. Se observó que el método de Jaffé cinético sin compensación arrojó resultados de creatinina sérica, que al trasladarse a ecuaciones que determinan la VFG, dejaron un margen de error inaceptable (circunstancia que no se obser¡vó de igual forma en el JCCC). Se concluye que la VFG estimada por fórmulas a partir de Cr dosadas por los métodos JC y JCCC, tomando como referencia el método enzimático, no son comparables.(AU)

In order to do early detection of chronic renal disease, many scientific societies have recommended to report a GFR estimate usinga prediction equation associated with serum creatinine measurement, as a marker of renal function. Faced with the wide variety of available creatinine measurement, as a marker of renal function. Faced with the wide variety of available creatinine methodologies in this country, professionals have a dilemma: the choice of which method must be used to quantify creatinine. The purpose of this study is to analyze whether the estimates of GFR usingcreatinine measures by different methods are comparable. Although no statistically significant differences between Cr quantified by Kinetic Jaffe method (JC), compensated kinetic Jaffe (JCCC) and enzymatic (ENZ) were observed, no good correlation was obtained between them. It was observed that the kinetic Jaffe method without compensation showed results that, beingincorporated in equations that determine the GFR, left an unacceptable margin of error (a circumstance that was not observed in the JCCC). Conclusion: GFRestimated with formulas usingcreatinine measured by JC and JCCC compared to ENZ are not comparable.(AU)

Visando detectar precocemente a doenþÒ renal cr¶nica, muitas sociedades científicas tÛm recomendado incorporar aos relatórios de laboratório a velocidade de filtraþÒo glomerular (VFG) estimada por fórmulas associadas a creatinina plasmática (Cr) como marcador de funþÒo renal. Frente O variedade de metodologias disponíveis na Argentina, os bioquímicos se encontram frente ao dilema da seleþÒo do método a utilizar para quantificar Cr. O objetivo deste trabalho é analisar se a VFGestimada por fórmulas a partir de Cr dosadas por diferentes métodos sÒo comparáveis. Embora nÒo se observassem diferenþas estatisticamente significativas entre as Cr quantificadas pelos métodos Jaffé cinético (JC), Jaffé cinético com compensaþÒo (JCCC) e enzimático (ENZ), nÒo foi obtida uma correlaþÒo adequada entre os mesmos. Observouse que o método de Jaffe cinético sem compensaþÒo deuresultados de creatinina sérica, que ao se trasladarem para equaþ§es que determinam a VFG, deixaram uma margem de erro inaceitável (circunstÔncia que nÒo se observoude igual forma no JCCC). ConclusÒo: a VFGestimada por fórmulas a partir de Cr dosadas pelos métodos JC e JCCC, tomando como referÛncia o método enzimático, nÒo sÒo comparáveis.(AU)

Detección precoz de Enfermedad Renal Crónica / Early detection of Chronic Kidney Disease. Multidisciplinary document / Detecção precoce de doença renal Crônica

El aumento de la prevalencia de pacientes con Enfermedad Renal Crónica (ERC), la ha convertido en un problema de Salud Pública mundial, no sólo por el requerimiento de tratamiento sustitutivo renal, sino porque el desarrollo de enfermedad cardiovascular constituye la primera causa de muerte en estos pacientes. La creatinina plasmática (Crp) no siempre resulta un marcador precoz, pues su valor en sangre se eleva por encima del límite superior del intervalo de referencia cuando el Índice de Filtrado Glomerular (IFG) disminuye a la mitad. La medición del IFG con marcadores exógenos es el mejor indicador para evaluar la función renal (FR), aunque su uso en la práctica clínica se reserva para situaciones especiales. El Índice de depuración de creatinina (IDC) puede presentar errores por causa de una mala recolección de orina. Además, sobreestima el IFG debido a que la creatinina, además de ser excretada, se secreta a nivel tubular. La utilización de fórmulas asociadas a Crp está recomendada por la mayoría de las sociedades científicas. La ecuación MDRD-4 se adoptó por consenso "IFGe (mL/min/1,73 m²)= 186 x (Crp) -1.154 x (edad) -0.203 x (0,742 mujer) x (1,212 raza negra)". El factor inicial es 175 cuando el resultado de Crp es trazable a Espectrometría de Masa con Dilución Isotópica (EM-DI). Esta fórmula no es aplicable en casos de embarazadas, hospitalizados, menores de 18 o mayores de 70 años, amputados, etc. Dado que la medición de Crp es la mayor fuente de error para el cálculo de IFGe, el laboratorio debe validar su procedimiento analítico para determinar creatinina. El Error Total no debe superar el 8% para que no produzca un aumento mayor del 10% en la estimación del IFG. Para la detección de ERC se recomienda: 1) Estimar la VFG utilizando la ecuación MDRD-4 asociada a Crp (fuerza de recomendación C). 2) Informar valores de más de 60 mL/min/1,73 m² sólo como "mayor de 60" y los valores menores de 60, como el número exacto obtenido; 3) Excluir en sistemas con cálculos automáticos las situaciones que limitan el uso de la ecuación.

The increase in prevalence of patients with Chronic Kidney Disease (CKD) has turned it a worldwide public health problem not only due to its requirement of a kidney replaceable treatment, but also because cardiovascular disease is now the main cause of death among these patients. Plasma Creatinine (Crp) is not always an early marker, due to the fact that its blood levels exceed the highest limit of the reference range when the Glomerular Filtration Rate (GFR) decreases to a half. GFR measurement with exogenous markers is the best indicator to test renal function (RF), although its use in the clinical practice is only restricted to special situations. Creatinine Clearance (CC) may have errors caused by an inadequate urine collection. Moreover, it overestimates the GFR considering that creatinine is not only excreted but also secreted at the tubular level. The utilization of formulas associated to Crp is recommended by most of the Scientific Societies. The MDRD-4 equation has been adopted by consensus "eGFR (mL/min/1.73 m²)= 186 x (Crp) -1.154 x (age) -0.203 x (0.742 woman) x (1.212 black people)". When the creatinine results are traceable to isotope Dilution/Mass Spectrometry reference method, the initial factor is 175. This formula does not apply to pregnant women, hospitalized patients, people under 18 or older than 70 years old, amputees, etc. Given that the measurement of Crp is the biggest cause of error for the calculation of eGFR, the lab should validate the analytical procedure to determine creatinine. The Total Error should not exceed 8% in order not to yield an increase over 10% of GFR estimation. For CKD detection, it is recommended as follows: 1) Estimate the GFR using MDRD-4´s equation associated to Crp. (Strength of Recommendation C); 2) Report values over 60 mL/min/1.73 m² only as "over 60" and values under 60 as the exact number obtained; 3) Exclude from automatic calculation systems, situations that limit the use of the equation.

Função Renal de pacientes de unidade de terapia intensiva: creatinina plasmática e proteína carreadora do retinol urinária (RBPu / Renal Function of Intensive care unit patients: plasma creatinine and urinary retinol-binding protein (uRBP)

A avaliação da disfunção renal pelos marcadores usuais não tem determinado impacto na redução da incidência da insuficiência renal aguda (IRA) nos pacientes de terapia intensiva. Este estudo avaliou 100 pacientes admitidos em uma unidade de terapia intensiva (UTI) quanto às características demográficas; a relação entre creatinina plasmática e proteína carreadora do retinol (RBPu) e as variáveis clínico-laboratoriais; e a sensibilidade e a especificidade da RBPu. A amostra caracterizou-se como geriátrica (63,4±15,6 anos), do sexo masculino (68%), 47% dos pacientes tiveram tratamento clínico e 53% cirúrgico. A coleta de dados foi realizada no período de 13,9±8,3 horas após a admissão na UTI. A análise dos resultados mostrou associação entre a creatinina plasmática e as variáveis: gênero (p-0,026), idade (p-0,038), uso de droga vasoativa (p-0,003), proteínúria (p-0,025), APACHE II (p-0,000), uréia (p-0,000), potássio (p-0,003) e clearance de creatinina estimado (p-0,000). A RBPu mostrou associação com um número maior de variáveis: peso (IMC), uso de ventilação invasiva (p-0,000), uso de anti-inflamatório não-hormonal (p-0,018), uso de droga vasoativa (p-0,021), temperatura>37,5ºC (p-0,005), proteinúria (p-0,000), bilirrubinúria (p-0,004), fluxo urinário (p-0,019), pressão arterial diastólica mínima (p-0,032), pressão arterial sistólica mínima (p-0,029), APACHE II (p-0,000), creatinina (p-0,001), uréia (p-0,001), clearance de creatinina estimado (p-0,000) e uma tendência a associação com os antecedentes clínicos (doença renal, vasculopatia e neoplasia). A creatinina plasmática e a RBPu apresentaram associação com a fração de excreção de sódio (FENa) quando os dados foram submetidos à análise univariada. O estudo referente à sensibilidade e especificidade da RBPu utilizando a curva ROC (Relative Operating Characteristics) mostrou que pacientes com RBPu maior que 1,47 mg/l têm aproximadamente quatro chances de apresentarem creatinina acima de 1,2 mg/dl (intervalo de confiança - 95%, erro padrão - 0,072). A acurácia global da RBPu, como teste diagnóstico, foi fraca. A RBPu, apesar das fracas sensibilidade e especificidade encontradas no estudo, pode ser considerada na clínica, o marcador de melhor desempenho diagnóstico em pacientes com risco para a ocorrência de IRA quando comparada aos marcadores utilizados rotineiramente.

The early assessment of renal dysfunction using common markers has not determined an impact on lower incidence of acute renal failure (ARF) in intensive care patients, which remains alarming high. This study followed-up 100 patients admitted to an intensive care unit (ICU) and assessed demographic variables as well as plasma creatinine and urinary retinol-binding protein (uRBP) ratio with clinical and laboratory variables within the first hours of admission to the ICU. The sample was characterized as geriatric (63.4±15.6 years), male (68%), 47% clinical and 53% surgical patients. Data were gathered 13.9±8.3 hours after admission to ICU. Statistical analysis showed association between plasma creatinine and the following variables: gender (p-0.026), age (p-0.038), use of vasoactive drugs (p-0.003), proteinuria (p-0.025), APACHE II (p-0.000), urea (p-0.000), potassium (p-0.003) and estimated creatinine clearance (p-0.000). uRBP correlated with more variables: weight (BMI), use of invasive ventilation (p-0.000), use of nonsteroidal anti-inflammatory drugs (p-0.018), use of vasoactive drugs (p-0.021), temperature >37.5ºC (p-0.005), proteinuria (p-0.000), bilirubinuria (p-0.004), urinary flow (p-0.019), minimal diastolic pressure (p-0.032), minimal systolic pressure (p-0.029), APACHE II (p-0.000), creatinine (p-0.001), urea (p-0.001), estimated creatinine clearance (p-0.000). uRBP also tended to associate with clinical past medical history (renal disease, vasculopathy and neoplasm). FENa correlated with plasma creatinine and uRBP in univariate analysis. The ROC (Receiver Operating Characteristic) curve demonstrated that patients with uRBP >1.47 mg/l are four times more likely to have creatinine >1.2 mg/dl (95% confidence interval, standard error, 0.072). The global accuracy of uRBP as a diagnostic test was poor. Although uRBP sensibility and specificity were not very high in the study, in clinical practice it might be considered the better marker regarding diagnostic performance in patients at risk of developing ARF, as compared with other markers routinely used. Moreover, uRBP has other features of a good diagnostic test - it is a practical and non-invasive method, and its cost may drop as the test becomes more frequently requested.