Dyego José de Araújo Brito

Monitoring renal function: measured and estimated glomerular filtration rates - a review

Chronic kidney disease (CKD) is a world-wide public health problem, with adverse outcomes of kidney failure, cardiovascular disease, and premature death. This finding has led to the hypothesis that earlier recognition of kidney disease and successful intervention may improve outcome. The National Kidney Foundation, through its Kidney Disease Outcomes Quality Initiative (K/DOQI), and other National institutions recommend glomerular filtration rate (GFR) for the definition, classification, screening, and monitoring of CKD. Blood creatinine clearance, the most widely used clinical marker of kidney function, is now recognized as an unreliable measure of GFR because serum creatinine is affected by age, weight, muscle mass, race, various medications, and extra-glomerular elimination. Cystatin C concentration is a new and promising marker for kidney dysfunction in both native and transplanted kidneys. Because of its low molecular weight, cystatin C is freely filtered at the glomerulus and is almost completely reabsorbed and catabolized, but not secreted, by tubular cells. Given these characteristics, cystatin C concentration may be superior to creatinine concentration in detecting chronic kidney disease. This review aims to evaluate from recent literature the clinical efficiency and relevance of these GFR markers in terms of screening CKD.

Prevalência e fatores de risco para insuficiência renal aguda no pós-operatório de revascularização do miocárdio

OBJECTIVE To determine the prevalence, risk factors, and the clinical outcome of patients undergone coronary artery bypass grafting who progressed with Acute Renal Failure (ARF). METHODS A retrospective cohort prospective study was performed from data of 186 patients undergone surgery from January 2003 through June 2006. The stored data were analyzed using the software STATA 9.0. RESULTS The prevalence of ARF was of 30.6% (57/186). In 7.0% (4/57) dialysis therapy was needed. The mean age of patients with and without ARF progression was 62.8 (+/-9.4) years and 61.3 (+/-8.8) years respectively (P=NS). CPB time >115 min (p= 0.011) and cross-clamp time >85 min (p=0.044) were related to ARF by the univariate analysis. The need for intra-aortic balloon (P= 0.049), mechanical ventilation >24h (P = 0.006), Intensive Care Unit (ICU) stay > three days (P< 0.0001), bradycardia (P= 0.002), hypotension (P= 0.045), arrhythmia (P=0.005) and inotropic infusion (P= 0.0001) were higher in the ARF group. Only the ICU stay longer > 3 days showed statistical correlation with ARF by the multivariate analysis (P=0.018). The mortality rate with and without ARF was 8.8% (five cases) and 0.8% (one case) respectively (P=0.016), but it reached 50% (2/4) in dialytic patients. CONCLUSION ARF was a frequent and severe postoperative complication associated with higher mortality and longer ICU stay, which presented as risk factors: longer CPB and cross-clamp times, mechanical ventilation > 24h and hemodynamic instability.

Valor da equação Cockcroft-Gault na triagem de função renal reduzida em pacientes com hipertensão arterial sistêmica

INTRODUCTION Arterial hypertension is a worldwide public health problem and one of the major risk factors for chronic kidney disease development. METHODS In order to compare the Cockcroft-Gault (CG) equation with serum creatinine and 24-hour creatinine clearance (CrCl) for the screening of reduced renal function, a cross-sectional study of 198 hypertensive patients was undertaken at a basic health unit. The demographic, nutritional, and clinical laboratory data were analyzed. Renal function was assessed by serum creatinine and 24hour CrCl. Glomerular filtration rate (GFR) was also estimated according to Cockcroft-Gault equation. RESULTS The patients had a mean age of 60.6 ± 11.6 years-old, and 73.7% were female. The prevalence of serum creatinine > 1.2 mg/dL was 7.6% and the prevalence of GFR < 60 mL/minute was 24.2%, when evaluated by the CrCl and CG equation. Reduced GFR was observed in older male patients, with lower body mass index, normal values of fasting blood glucose, and higher levels of serum uric acid and of systolic blood pressure. DISCUSSION The prevalence of decreased renal function among hypertensive patients varies considerably, depending on the laboratory investigation used. CG-estimated CrCl has shown to be more accurate than serum creatinine for assessing GFR. CONCLUSIONS CG-estimated CrCl was highly similar to 24-hour CrCl, proving to be a reliable primary care screening test for the early diagnosis of renal impairment in hypertensives.

Abdominal obesity and reduction of glomerular filtration

The objective was to evaluate the association between nutritional status and the glomerular filtration rate (GFR) in remaining quilombolas. Cross-sectional study carried out on 32 remaining quilombola communities in the municipality of Alcântara-MA. The nutritional indicators (IN) used were: body mass index (BMI); Waist circumference (WC); Waist-to-hip ratio (WHR); Waist-to-height ratio (WHtR); conicity index (CI) and estimated visceral adipose tissue (VAT). GFR was estimated from the CKD-EPI creatinine-cystatin C formula. The Shapiro Wilk test was used to evaluate the normality of the quantitative variables. In order to compare the second IN sex, the chi-square test was applied. The Anova or Kruskal-Wallis tests were used to verify the association between IN and GFR. Of the 1,526 remaining quilombolas studied, 89.5% were black or brown, 51.2% were women, 88.6% belonged to economic classes D and E and 61.2% were farmers or fishermen. Clinical investigation revealed 29.2% of hypertensive patients, 8.5% of diabetics and 3.1% with reduced GFR. The BMI revealed 45.6% of the remaining quilombolas with excess weight. When compared to men, women presented a higher prevalence of overweight by BMI (56.6% vs 33.8%, p <0.001) and abdominal obesity CC (52.3% vs 4.3%), WHR (76,5% vs 5.8%), WHtR (82.3% vs 48.9%) and VAT (27.1% vs 14.5%) (p <0.001). Comparing the means of IN according to the GFR, it was observed that the higher the mean value of the IN lower the GFR (p <0.05). The GFR reduced with increasing mean values of nutritional indicators of abdominal obesity, regardless of sex.

Sodium excretion and associated factors in urine samples of African descendants in Alcântara, Brazil: a population based study

Abstract In most countries, salt intake has been excessive and constitutes one of the main risk factors for disease development, especially hypertension. Factors such as age, gender, sedentary lifestyle, smoking, African descent, obesity, dietary habits and family history of hypertension may be associated with high blood pressure. Studies show a positive association between the excretion of sodium and increased blood pressure. We evaluated the urinary excretion of sodium and associated factors in isolated urine samples of African descendants from remaining Quilombos. We performed a cross-sectional, population-based study with 1162 African descendants living in remaining quilombos in Alcântara, Maranhão, Brazil. Demographic, nutritional, clinical and laboratory data were analyzed. Urinary sodium excretion was estimated using the Kawasaki equation. A multivariate linear regression model was used to identify the variables related to sodium excretion. The average age was 37.6 ± 11.8 years and 51.2% were women. The prevalence of hypertension was 21.3%. The average urinary excretion of sodium was high, especially among the hypertensive (217.9 ± 90.1 vs. 199.2 ± 83.0 mmol/d; p = .002). After an adjusted analysis, only the waist circumference (odds ratios (OR) = 1.16; confidence intervals(CI)95%: 1.03–1.30), triglyceride (OR = 1.13; CI95%: 1.05–1.22), systolic blood pressure (OR = 1.19; CI95%: 1.08–1.32) and Chronic Kidney Disease Epidemiology (CKD-EPI;OR = 1.24; CI95%: 1.15–1.35) remained related to urinary sodium excretion. African descendants had a high rate of sodium excretion, especially among those who had hypertension. Abdominal adiposity, triglyceride and systolic blood pressure levels and renal function by CKD-EPI equation were associated to urinary sodium excretion.