Early Impairment Of Renal Function Research Articles

Could occupational physical activity mitigate the link between moderate kidney dysfunction and coronary heart disease?

BackgroundChronic kidney disease is now regarded as a risk factor for cardiovascular disease. The impact of occupational or non-occupational physical activity (PA) on moderate decreases of renal function is uncertain. ObjectivesWe aimed to identify the potential association of PA (occupational and leisure-time) on early decline of estimated glomerular filtration rate (eGFR) and to determine the potential mediating effect of PA on the relationship between eGFR and heart disease. MethodsFrom the PRIME study analyses were conducted in 1058 employed men. Energy expended during leisure, work and commuting was calculated. Linear regression analyses were used to determine the link between types of PA and moderate decrements of eGFR determined with the KDIGO guideline at the baseline assessment. Cox proportional hazards analyses were used to explore the potential effect of PA on the relationship between eGFR and heart disease, ascertained during follow-up over 10years. ResultsFor these employed men, and after adjustment for known confounders of GFR change, more time spent sitting at work was associated with increased risk of moderate decline in kidney function, while carrying objects or being active at work was associated with decreased risk. In contrast, no significant link with leisure PA was apparent. No potential mediating effect of occupational PA was found for the relationship between eGFR and coronary heart disease. ConclusionOccupational PA (potential modifiable factors) could provide a dual role on early impairment of renal function, without influence on the relationship between early decrease of e-GFR and CHD risk.

Role of cystatin C in renal damage and the optimum cut-off point of renal damage among patients with type 2 diabetes mellitus.

The aims of the present study were to evaluate the roles of serum cystatin C (SCysC) and urinary cystatin C (UCysC) in renal function impairment and investigate the optimum cut-off point for renal function impairment among patients with type 2 diabetes mellitus (DM). A total of 742 inpatients and outpatients with type 2 DM (age, 20–75 years) were enrolled in this population-based cross-sectional study. The levels of SCysC and UCysC were determined and the odds ratios (ORs) and 95% confidence interval (CIs) of the calculated risk ratios of the different renal damage indicators were obtained. The levels of UCysC, urinary β2-microglobulin (Uβ2-MG), urinary albumin (UALB) and SCysC in the renal function impairment groups were observed in the following order: GFR-C>GFR-B>GFR-A (P<0.05 or P<0.01). According to the levels of GFR were divided into 4 groups, group GFR-A ≥ 80ml/min, GFR-B group 50–80 ml/min, group Ccr-C 20–50 ml/min, group GFR-D <20 ml/min. Following adjustment for age and gender, multivariate correlation analysis results revealed that levels of Uβ2-MG, UCysC and UALB negatively correlated with the glomerular filtration rate (GFR; P<0.05 or P<0.01). In addition, the duration of DM and the levels of SCysC and serum uric acid were shown to positively correlate with the GFR (P<0.05 or P<0.01). ORs for early renal function impairment significantly increased from the DM duration category of four years (OR, 1.74; 95% CI, 1.54–1.92). Receiver operating characteristic analysis demonstrated that the optimum DM cut-off point was four years, in which 60.79% sensitivity and 69.66% specificity were observed. Therefore, UCsyC levels may be used as an efficient indicator for the evaluation of early renal function impairment among patients with type 2 DM. In addition, renal lesions may initially occur in the renal tubule and then form in the renal glomerulus of patients with type 2 DM.

Deletion of ErbB4 accelerates polycystic kidney disease progression in cpk mice

ErbB4 is highly expressed in the cystic kidneys with polycystic kidney diseases. To investigate its potential role in cystogenesis, cpk mice carrying a heart-rescued ErbB4 deletion were generated. Accelerated cyst progression and renal function deterioration were noted as early as 10 days postnatally in cpk mice with ErbB4 deletion compared to cpk mice, as indicated by increased cystic index, higher kidney weight to body weight ratios and elevated BUN levels. No apparent defects in renal development were noted with ErbB4 deletion itself. Increased cell proliferation was predominately seen in the cortex of cystic kidneys with or without ErbB4 deletion. However, there was significantly more cell proliferation in the cyst-lining epithelial cells in cpk mice with ErbB4 deletion. TUNEL staining localized apoptotic cells mainly to the renal medulla. There were significantly more apoptotic cells in the cyst-lining epithelial cells in ErbB4-deleted cpk kidneys, with decreased levels of cyclin D1, increased levels of p21, p27 and cleaved caspase 3. Thus, lack of ErbB4 may contribute to elevated cell proliferation and unbalanced cell apoptosis, resulting in accelerated cyst formation and early renal function deterioration. These studies suggest that the high level of ErbB4 expression seen in cpk mice may exert relative cytoprotective effects in renal epithelia.

Is microalbuminuria a risk factor for hypertension in children with solitary kidney?

The correlations between ambulatory blood pressure measurements (ABPM) and serum cystatin C (Cys C), serum creatinine (Cr), microalbumin (MA), and β2-microglobulin (β2-MG) levels in 24 h (24-h) urine were analyzed in children with solitary kidney (SK) and compared to healthy children. Fifty children with normal functioning SK and 25 controls were studied. The ABPM, serum Cys C, serum Cr, MA, and β2-MG levels in 24-h urine were measured in all children. Clinical symptoms and signs, laboratory results, urinary ultrasonography, voiding cystourethrography, and Dimercaptosuccinic acid (DMSA) scintigraphy results were recorded in the SK group. Four patients with Wilms' tumor and two with renal scarring were excluded from the study. The mean ages of the SK group and controls were 9.6 ± 3.6 and 9.3 ± 3.3 years, respectively. The serum Cys C and Cr levels, 24-h urinary β2-MG and MA levels were similar in both groups (p > 0.05). However, 24-h urinary MA excretion was higher in patients living with SK more than 5 years (p = 0.01). Standard deviation scores of ABPM parameters showed no significant correlation with serum Cr, serum Cys C, MA, and β2-MG in 24-h urine of both groups. Children with SK have increased 24-h urinary MA excretion in the long term, and need prolonged follow-up to detect early deterioration of renal function and to prevent end-organ damage later in life.

Postasphyxial renal injury in newborns as a prognostic factor of neurological outcome

Objective: To estimate if an acute postasphyxial renal injury in newborns could indicate a neurological outcome.Methods: We conducted a prospective clinical trial on 50 full-term newborns with 5-minute Apgar score <7 (asphyxiated group) and a control group of 50 full-term newborns with 5-min Apgar score ≥7 (non-asphyxiated group). Renal function was assessed on the third day of life by serum values of creatinine, cystatin C and β2-microglobulin (β2M) and glomerular filtration rate (GFR). All newborns had brain and renal ultrasonography at early stages and were followed by Amiel-Tison Neurological Assassment (ATNA) throughout the first year of life.Results: Mean GFR was significantly lower in asphyxiated than in non-asphyxiated group (22.08 ± 6.66 ml/min/1, 73 m2 versus 35.42 ± 2.26 ml/min/1, 73 m2; p < 0.001) and serum values of creatinine, cystatin C and β2M were significantly higher (1.13 versus 0.66 mg/dl; 3.92 versus 1.52 mg/l; 1.53 versus 0.99 mg/l; p < 0.001). In asphyxiated group ATNA results throughout the first year of life significantly correlated with renal function (p < 0.01). A correlation of ATNA with Apgar score at 5 min, Sarnat and Sarnat staging of hypoxic ischemic encephalopathy and brain and renal ultrasonography has also been significant (p < 0.01).Conclusions: Our study showed a significant correlation between early impairment of renal function due to neonatal asphyxia with neurological outcome at the end of the first year of life.

Intrarenal resistance index for the assessment of acute renal injury in a rat liver transplantation model

BackgroundAcute kidney injury (AKI) is a common complication after liver transplantation (LT) and associated with a high mortality. The renal resistive index (RI) is used to assess early renal function impairment in critical care patients. However, limited data are available concerning changes of renal RI and the development of AKI early after reperfusion. We approached to investigate the changes of renal RI and AKI after reperfusion in a rat liver transplantation model.MethodsRats were randomly divided into sham group or LT group. Ten rats in each group were used for the hemodynamic study and twenty for Doppler measurements during the procedure. Ten rats were sacrificed 30 min or 2 h after the reperfusion. We harvested kidneys, serum and urine for further analysis of the renal function.ResultsThe intrarenal RI increased significantly in the anhepatic stage and decreased significantly after the reperfusion in the LT group compared with sham group (P < 0.05). AKI was seen after the reperfusion in the LT group. No correlation was noted between the RI and renal function parameters 30 min after reperfusion.ConclusionsThe intrarenal RI increased significantly during the anhepatic stage, and decreased significantly early after the reperfusion. Intrarenal RI was unable to assess renal function in a rat liver transplantation model.

INCREASED URINARY ADIPONECTIN LEVEL IS ASSOCIATED WITH CONTRAST-INDUCED NEPHROPATHY IN PATIENTS UNDERGOING PCI

Contrast-induced nephropathy (CIN) is one of major complications in patients undergoing PCI. We prospectively examined the association of urinary adiponectin (UAPN), a sensitive marker for early renal function impairment, with CIN. We enrolled 208 patients without severe hepatic and renal function

Early renal dysfunction after contrast media administration despite prophylactic hydration

The actual incidence of renal dysfunction after contrast media administration seems to be underestimated, especially in the context of epidemiological data. There are only few data concerning the monitoring of impaired kidney function within a few hours after iodine contrast medium application. Hence, the purpose of this study is to observe the incidence of early renal function deterioration within 12–18 h after administration of iodine contrast media in patients scheduled for elective coronary angiography, who were intravenously and orally hydrated. In addition, the project aims to reclassify the contrast induced nephropathy phenomenon, by identification of early markers of renal dysfunction. Morphology, electrolytes, blood urea nitrogen (BUN), creatinine, low-density lipoprotein cholesterol, triglycerides, high-density lipoprotein, and total cholesterol levels were assessed with the use of typical laboratory techniques in 319 patients referred for coronary angiography. We demonstrated that early deterioration of renal function in patients 12–18 h after administration of contrast during imaging tests (even when appropriate prophylactic hydration was used), may occurred just as an increase (or no change) of serum creatinine level and BUN level and a decrease of creatinine clearance and glomerular filtration rate. Depending on the parameter, the phenomenon can be found in 13–28 % of all respondents. Early renal function impairment defined as above was almost 2 and 2.22 × 103 times (respectively) more frequently observed in our study than contrast induced nephropathy defined by current definitions.

Diabetes With Preserved Renal Function Is an Independent Risk Factor for Renal Function Deterioration After Coronary Computed Tomography Angiography

Diabetes mellitus (DM) and high fasting glucose levels are reportedly risk factors for contrast-induced nephropathy after invasive coronary angiography in patients with renal dysfunction. Cystatin C (CyC) is a sensitive marker for detecting early impairment of renal function. Using CyC, we investigated whether DM would be a risk for worsening renal function after coronary computed tomography angiography (CCTA) in patients with preserved renal function. Two hundred twenty-eight patients scheduled for CCTA were enrolled. The serum CyC at preprocedure and 1 day after procedure, urinary microalbumin at preprocedure, and oral fluid volume for 24 hours after procedure were measured. The percentage changes in CyC from preprocedure to 1 day after procedure (%CyC) were also calculated. Ninety-eight patients had DM. The %CyC and urinary microalbumin were significantly greater in DM patients than in non-DM patients. The percentage of patients showing a %CyC of 10% or greater was significantly greater in DM patients than in non-DM patients (27% vs 8%, P < 0.01). Using multivariate regression analysis, oral fluid volume and urinary microalbumin were independent predictors for a %CyC of 10% or greater in DM patients (β = - 0.428 [P < 0.0001] and β = 0.464 [P < 0.0001], respectively). Diabetes mellitus is a risk factor for worsening changes in renal function after CCTA, even in patients with preserved renal function. In particular, elevated microalbuminuria and low oral fluid intake are high-risk factors for renal functional deterioration.

Use of Serum Cystatin C in Assessment of Early Deterioration of Renal Function in Type 2 Diabetic Industrial Workers in Port Harcourt, Nigeria

Early detection of deterioration or impairment in renal function is critical in management of diabetic patients. Serum cystatin C may be the most sensitive indicator of glomerular filtration rate (GFR) in a clinical environment. We compared cystatin C with creatinine, the Cockcroft-Gault (C-G) formular, and the Modification of Diet in Renal Disease (MDRD) equation for the assessment of early decreased renal function in 50 type 2 diabetic patients with and without significant renal impairment (GFR; 8-205 ml/min/1.73m 2 ).Relationships of cystatin C, creatinine, and iohexol clearance were linearized using simple regression model and diagnostic efficiency calculated. In our study population, cystatin C (P<0.001) was better correlated with glomerular filtration rate (GFR) (r=0.922) than were creatinine (r=743), Cockcroft-Gault (C-G)formular (r=0.755) and Modification of Diet in Renal Disease (MDRD) equation (r=0.818). Mean cystatin C concentrations showed step wise statistically significant increases as GFR reduces, allowing very early identification of reduction in renal function. At 90ml/min/1.73m 2 and 75ml/min/1.73m 2 cut-points, diagnostic efficiencies of cystatin C (90% and 93%) were better than those of the other variables (80%-84% and 86%-89%, respectively; P = 0.01). All data supported the value of serum cystatin C compared with conventional estimates based on serum creatinine measurement for detecting very early reduction of renal function. Use of cystatin C to measure renal function will make for early detection, prevention, and treatment of diabetic nephropathy in type 2 diabetics.

Urinary Platelet-Derived Growth Factor-BB as an Early Marker of Nephropathy in Patients with Type 2 Diabetes: An Egyptian Study

Background: Diabetic nephropathy (DN) is one of the most serious complications of diabetes worldwide. Strong evidence suggests that several growth factors may contribute to the initiation and progressive fibrosis of DN. Recently, there is an overexpression of platelet-derived growth factor (PDGF) in renal biopsies from patients with DN. This study aimed to investigate the clinical significance of urinary PDGF-BB level in type 2 diabetic patients with and without nephropathy and to evaluate its relationship with various clinical and laboratory parameters. Methods: Urinary levels of PDGF-BB were measured in 60 Egyptian type 2 diabetic patients categorized into three equal groups (normo-, micro-, and macroalbuminuria), according to urinary albumin level. In addition, 20 healthy subjects were selected to serve as controls. Results: The urinary PDGF-BB levels were significantly increased in type 2 diabetic patients as compared to controls (p < 0.001). Moreover, diabetics with micro- and macroalbuminuria had significantly higher levels than in those with normoalbuminuria (p < 0.001). Urinary PDGF-BB correlated positively with disease duration, low-density lipoprotein (LDL)-cholesterol, and urinary albumin and negatively with creatinine clearance in diabetic patients. In a multiple regression model, urinary PDGF-BB was strongly and independently associated with nephropathy in diabetic patients (β = −0.03, p < 0.001). Conclusions: PDGF-BB may play an important role in the initiation and progression of DN. It is considered as a good predictor for early deterioration of renal function in DN. Thus, measurement of urinary PDGF-BB in type 2 diabetic patients could be used for early detection of diabetic renal disease.

Comparison between Kidney and Hemoperfusion for Paraquat Elimination

The mortality rate of acute paraquat (PQ) poisoning depends on the PQ concentration in the blood. It has been shown that the kidneys eliminate PQ effectively. However, early renal function deterioration is frequently observed in acute PQ intoxication. This study is designed to compare the efficacy of PQ elimination with hemoperfusion (HP) and kidneys, taking into account the functional deterioration of the kidneys. The amount of renal and HP excretion of PQ were measured during the procedure of HP in patients with acute PQ intoxication. The PQ clearance and the actual amount of PQ elimination by the HP cartridge during the HP procedure were 111±11 mL/min (range; 13.2-162.2 mL/min) and 251.4±506.3 mg (range; 4.6-1,655.7) each. While, the renal clearance and actual amount of renal elimination of PQ was 79.8±56.0 mL/min (range; 9.7-177.0) and 75.4±73.6 mg (range; 4.9-245.8). As the creatinine clearance decreased, the PQ elimination by HP was as effective as or more effective than the renal elimination. In conclusion, early HP must be provided for life saving treatment in patients with acute PQ intoxication.

Between hyperfiltration and impairment: Demystifying early renal functional changes in diabetic nephropathy

Renal functional changes in diabetic nephropathy conventionally have been linked to progression of urinary albumin excretion. This paradigm was based on historic evidence noting that hyperfiltration occurred in the setting of normoalbuminuria and microalbuminuria and that loss of renal function began in the context of proteinuria. More contemporaneous research findings, using serum cystatin-C-based estimates of glomerular filtration rate (cC-GFR), have challenged this paradigm. Rather, the process of renal function loss appears to begin prior to the onset of proteinuria. In the 2nd Joslin Kidney Study on the Natural History of Microalbuminuria, over one-third of type 1 diabetes (T1DM) patients with microalbuminuria at the time of enrollment already had evidence of mild (cC-GFR < 90) or moderate (cC-GFR < 60 ml/min) renal function impairment. Understanding the mechanisms underlying this phenomenon of early renal function impairment may allow for interventions directed at altering or retarding early renal function decline. To date, serum uric acid and components of the TNFα pathway appear to be involved.

Serum cystatin C measured by a sol particle homogeneous immunoassay can accurately detect early impairment of renal function

A sol particle homogeneous immunoassay (SPIA) is a method to measure the serum cystatin C (cysC) level as a marker of the glomerular filtration rate (GFR). Recently, formulas to convert measured cysC to GFR have been developed. A total of 154 patients (46 +/- 18 years old) who had undergone renal biopsy, sodium thiosulfate clearance (C thio) and 24-h creatinine clearance (24-hCcr) tests were subjects for the study. Their serum cysC levels were determined by SPIA. Multiple regression analysis revealed C (thio) and age as independent variables for serum creatinine concentration (Cr), while only C thio affected cysC. The equations using Cr or cysC showed significant correlation with C thio. Receiver-operating curve ROC analysis revealed that cysC and 24-hCcr shared comparable power to detect patients with GFR < 90 or 60 ml/min/1.73 m2 (AUC = 0.862 and 0.943 vs. AUC = 0.842 and 0.943, respectively), while Cr (AUC = 0.881) and MDRD2 (AUC = 0.888) showed slightly inferior ability to detect 60 ml/min/1.73 m2 than other parameters in the female population. The cut-off point of cysC and Cr obtained from the ROC analysis demonstrated strong power to detect patients with C thio < 90 ml/min/1.73 m2 or C thio < 60 ml/min/1.73 m2. According to CKD stages, the mean values of each equation were significantly different, like that demonstrated by 24-hCcr. SPIA could determine cysC levels that detected early renal impairment. The accuracy of cysC to detect early renal impairment may be superior to that of Cr in females, while it would be comparable to that of CG or MDRD when they are corrected by sex and age. Both cysC itself and cysC equations are effective to monitor the progress of renal impairment. The future standardization of cysC measurements and development of novel equation of cysC would contribute to the further improvement of GFR estimation in clinical practice.

Inhibition of mineralocorticoid receptors with eplerenone alleviates short-term cyclosporin A nephrotoxicity in conscious rats

Recent data indicate that aldosterone aggravates cyclosporin A (CsA)-induced nephrotoxicity. We examined whether the mineralocorticoid receptor (MR) blocker eplerenone (EPL) antagonized early deterioration of renal function and blood pressure (BP) increase in CsA-treated rats. Male Sprague-Dawley rats received CsA (15 mg/kg/day i.p.) and/or EPL (100 mg/kg/day p.o.) for 21 days. After 2 weeks, arterial, venous and urinary bladder catheters were implanted and the rats were trained to accept a restraining device allowing arterial blood sampling and direct measurement of BP and renal function. BP was measured on-line in conscious rats. CsA significantly increased systolic BP: 139 +/- 4 versus 134 +/- 2 mmHg, reduced body weight gain: -5 +/- 6 versus 36 +/- 7 g, glomerular filtration rate (GFR): 1.02 +/- 0.16 versus 2.64 +/- 0.27 ml/min, renal blood flow (RBF): 5.3 +/- 2.4 versus 13.5 +/- 2.1 ml/min and lithium clearance (C(Li+)): 0.16 +/- 0.04 versus 0.26 +/- 0.07 ml/min compared to controls. These changes were prevented by simultaneous EPL treatment: systolic BP, 130 +/- 4 mmHg; weight gain, 53 +/- 7 g; GFR, 1.67 +/- 0.26 ml/min; RBF, 12.3 +/- 2.1 ml/min and C(Li+), 0.27 +/- 0.03 ml/min. Analysis of kidney morphology after the CsA treatment showed hyaline vacuolization in tubules and vascular depositions in arterioles; these changes were less pronounced after combination therapy. No significant changes were seen regarding haemoglobin, haematocrit, plasma renin and vasopressin, plasma and urinary sodium, potassium, or osmolality. MR blockade by EPL prevented short-term alterations in GFR, RBF and hypertension associated with CsA nephrotoxicity. We conclude that the aldosterone-MR pathway contributes markedly to the renal toxicity induced by this calcineurin inhibitor.

Epidemiology of digitalis medication. Results of the Munich blood-pressure study

As part of a blood-pressure survey in Munich, some of its inhabitants aged 30-69 years were asked by questionnaire about any digitalis medication. Chemically defined glycosides were taken by 127 of 1827 persons (7%), two-thirds of them older than 60 years, for clinically compensated chronic heart failure. Using the equation of Cockcroft and Gault to calculate creatinine clearance, it was below 80 ml/min and thus indicative of early impairment of renal function in more than 50%. In 44% the prescribed daily dose of glycoside corresponded to the calculated maintenance dose, 29% had less and 27% had taken more. None had clinical signs of digitalis intoxication. ECG changes possibly due to digitalis were much less common than had been expected. Sinus rhythm was present in 93%. More than 50% did not know why they were taking digitalis and 80% were taking two or more drugs at the same time. Since more than half had signs of early renal function impairment, creatinine clearance should be taken into account when determining the dosage of a digoxin preparation especially in elderly patients; alternatively, digitoxin should be prescribed. The survey also showed that a large number of persons on glycoside medication did not take the drug regularly.

The Combination of Cystatin C and Serum Creatinine Improves the Monitoring of Kidney Function in Patients with Diabetes and Chronic Kidney Disease

Pucci et al. (1) recently reported their study of the use of cystatin C (cysC) to detect decreases in renal function in patients with diabetes. CysC had an advantage over other methods only for detecting very early impairment of renal function [glomerular filtration rate (GFR) < 90 and 75 mL · min−1 · (1.73 m2)−1], whereas detection of the 70 patients with GFR <60 studied by Pucci et al.(1) was not improved by use of cysC compared with conventional estimated GFR estimations (e-GFR) predicted by Cockcroft and Gault (CG) and Modification of Diet in Renal Disease (MDRD) equations. Better GFR estimations are required for those patients considered to have chronic kidney disease (CKD) according to the new American Diabetes Association recommendations, particularly to assess the progression of their CKD, which may not be accurately estimated by the CG and MDRD equations(2). Rule et al.(3) recently proposed a composite GFR estimation based on both serum …

Alterações renais nas doenças falciformes

A doença falciforme associa-se a anormalidades renais estruturais glomerulares e tubulares, alterações hemodinâmicas e da síntese dos hormônios renais (eritropoetina, renina e prostaglandinas). Estas se iniciam na infância, em conseqüência da anemia crônica, fluxo sangüíneo aumentado, e eventos de veno-oclusão intraparenquimatosos, principalmente na medular renal. Na doença SS, a taxa de filtração glomerular encontra-se elevada desde os primeiros anos de vida e decresce com a idade. Decorrente de anormalidade tubular distal está a hipostenúria com as manifestações clínicas de poliúria, noctúria, enurese e susceptibilidade a desidratação, diminuição da capacidade de acidificar urina e excretar potássio. As anormalidades de túbulo proximal se traduzem por secreção aumentada de creatinina e ácido úrico, reabsorção aumentada de fosfatos e b2-microglobulina. A hipersecreção de creatinina superestima a taxa de filtração glomerular (FG), tornando o clearance de creatinina impróprio como detector precoce da deterioração da função renal. A proteinúria ocorre em 29%-50% dos pacientes acima de 10 anos de idade; 2/3 destes evoluem para insuficiência renal crônica de evolução ruim. A literatura apresenta benefícios consistentes com o uso de inibidores de enzimas conversoras de angiotensina (IECA) na redução da proteinúria, que talvez tenha impacto na progressão da insuficiência renal. Microalbuminúria (MA) é um marcador sensível da glomerulopatia falcêmica que precede a proteinúria. Na população pediátrica documenta-se prevalência de 19%, estando associado com idade, síndrome torácica aguda, níveis de Hb baixos e altas de leucometrias. Recomenda-se screening para MA a partir de 10 anos de idade. Em andamento estudo multicêntrico com uso precoce de hidroxiuréia na prevenção das lesões orgânicas crônicas (Baby HUG).

Metabolic risk factors associated with serum creatinine in a non-diabetic population

Insulin resistance, low HDL-cholesterol and microalbuminuria are important components of the metabolic syndrome as defined by WHO. Insulin resistance and low HDL-cholesterol are also common in chronic kidney disease (CKD), but it is not clear whether they are early or late phenomenons in the development of renal failure. This study examined whether low-grade albuminuria (microalbuminuria), lipoprotein fractions, and the insulin/glucose ratio (IGR)-a surrogate marker of insulin resistance-were related to renal function (expressed as serum creatinine) in persons without diabetes and with apparently normal renal function. The study included 4,131 men and women aged 55-75 years from the cross-sectional Tromsø IV survey (1994-1995). Lifestyle factors, waist circumference and blood pressure were included in the analyses. Gender stratified multivariate analysis was used to assess the relationship between serum creatinine and microalbuminuria, lipoprotein fractions and IGR. Serum creatinine was positively associated with microalbuminuria in men (beta = 2.50, 95% confidence interval (CI) 0.66-4.34), but not in women. HDL-cholesterol and IGR were strongly associated with creatinine in both genders (HDL-cholesterol: Men: beta = -4.82, 95% CI -6.27 to -3.37; women: beta = -2.12, 95% CI -3.28 to -0.96. IGR: Second, third and fourth quartile compared with first quartile, men: beta = 0.94, 95% CI -0.63 to 2.51; 2.10, 95% CI 0.52-3.69 and 2.40, 95% CI 0.75-4.04; women: beta = 1.91, 95% CI 0.59-3.22; 2.61, 95% CI 1.28-3.95 and 3.20, 95% CI 1.80-4.60). These findings suggest that even early impairment of renal function may be associated with insulin resistance and dyslipidemia, regardless of renal albumin leakage.

Notable Steps in Obtaining Improved Estimates for Glomerular Filtration Rate

Knowledge of the glomerular filtration rate (GFR) is of crucial importance in the management of patients. In addition to a general evaluation of kidney function, a more precise assessment is valuable on many occasions, e.g., to detect early impairment of renal function, to allow correct dosage of drugs cleared by the kidneys, to monitor renal transplants, and to evaluate patients before use of potentially nephrotoxic radiographic contrast media. Determination of GFR with high accuracy requires the use of invasive techniques based on measuring the plasma clearance rate of injected substances that are excreted exclusively via glomerular filtration, e.g., inulin, 125I-iothalamate, iohexol, and 51Cr-EDTA. Such procedures are labor-intensive and not free of risk for the patient. The plasma or serum concentrations of endogenous substances, particularly creatinine, have been used as indicators of GFR for more than a century (1). The creatinine …