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

Association between estimated glomerular filtration rate and sodium excretion in urine of African descendants in Brazil: a population-based study

ABSTRACT Introduction: Excessive salt intake is a risk factor for the development of chronic kidney disease (CKD). Objective: To evaluate the association between estimated glomerular filtration rate (eGFR) and sodium excretion in urine samples of Brazilians of African ancestry. Methods: Cross-sectional, population-based study of 1,211 Brazilians of African ancestry living in Alcântara City, Maranhão, Brazil. Demographic, nutritional, clinical, and laboratory data were analyzed. The urinary excretion of sodium was estimated using the Kawasaki equation. Calculations of eGFR were based on the Chronic Kidney Disease Epidemiology Collaboration equation. Multivariate linear-regression model was used to identify the relationship between sodium excretion and eGFR. Results: Mean age was 37.5±11.7 years and 52.8% were women. Mean urinary excretion of sodium was 204.6±15.3 mmol/day and eGFR was 111.8±15.3 mL/min/1.73m2. According to multivariate linear regression, GFR was independently correlated with sodium excretion (&#946;=0.11; p<0.001), age (&#946;=-0.67; p<0.001), female sex (&#946;=-0.20; p<0.001), and body mass index (BMI; &#946;=-0.09; p<0.001). Conclusions: The present study showed that age, female sex, BMI, and correlated negatively with eGFR. Sodium excretion was the only variable that showed a positive correlation with eGFR, indicating that high levels of urinary sodium excretion may contribute to hyperfiltration with potentially harmful consequences

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

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

Filtração glomerular e fatores associados em hipertensos atendidos na atenção básica Glomerular filtration and associated factors in hypertensive individuals treated at primary care level

FUNDAMENTO: No Brasil, a hipertensão arterial (HA) constitui-se um dos principais fatores de risco para doença renal crônica (DRC). Recomenda-se o monitoramento da filtração glomerular (FG) para avaliação da função renal em hipertensos, posto que sua redução precede o aparecimento de sintomas. OBJETIVO: Avaliar a FG e fatores associados em hipertensos. MÉTODOS: Realizou-se estudo transversal no período de janeiro a junho de 2008, com 297 hipertensos com ou sem diabete melito (DM) tratados em uma unidade básica de saúde em São Luís-MA. Foram incluídos pacientes >20 anos e de ambos os sexos. Avaliaram-se dados sociodemográficos, estado nutricional, FG e microalbuminúria em urina de 24h, controle pressórico e glicêmico, creatinina sérica e lipidograma. RESULTADOS: A idade média foi 60,6 × 11,5 anos com predomínio do sexo feminino (75,1%), sobrepeso/obesidade (65,0%) e circunferência da cintura elevada (60,6%). A prevalência de FG 65 anos, que permaneceu após ajustamento. Para o grupo HA com DM houve associação da redução da FG com idade > 65 anos, tabagismo e obesidade, porém, após ajustamento, permaneceram idade e tabagismo. CONCLUSÃO: Nestes pacientes, a prevalência de FG 65 anos e tabagismo apresentaram-se como fatores associados à FG. Isto reforça a necessidade da avaliação sistemática da FG em hipertensos visando a prevenção secundária da doença renal crônica.BACKGROUND: In Brazil, arterial hypertension (AH) constitutes one of the main risk factors for chronic kidney disease (CKD). The monitoring of glomerular filtration (GF) is recommended for the assessment of kidney function in hypertensive individuals, as GF decrease precedes symptom onset. OBJECTIVE: To assess GF and its associated factors in hypertensive individuals. METHODS: A cross-sectional study was carried out from January to June 2008 in 297 individuals with arterial hypertension (AH) with or without diabetes mellitus (DM), treated at a primary care facility in the city of São Luís, Maranhão. Patients older than 20 years and of both sexes were included in the study. Sociodemographic and nutritional status data, GF rate and microalbuminuria levels in 24-hour urine were assessed, as well as blood pressure, glucose and serum creatinine levels and a lipidogram. RESULTS: Mean age was 60.6 × 11.5 years, with a predominance of the female sex (75.1%), overweight/obesity (65.0%) and large waist circumference (60.6%). The prevalence of GF 65 years, which remained after adjustment. For the AH group with DM, there was an association between reduced GF and age > 65 years, smoking habit and obesity. However, after the adjustment, age and smoking habit remained as associated factors. CONCLUSION: In these patients, the prevalence of GF 65 years and smoking habit were shown to be factors associated to GF. This reinforces the need to systematically evaluate GF in hypertensive individuals, aiming at the secondary prevention of chronic kidney disease

La Voz de Asturias : diario de información: Año VII Número 1827 - 1929 Febrero 26

Fundamento: No Brasil, a hipertensão arterial (HA) constitui-se um dos principais fatores de risco para doença renal crônica (DRC). Recomenda-se o monitoramento da filtração glomerular (FG) para avaliação da função renal em hipertensos, posto que sua redução precede o aparecimento de sintomas. Objetivo: Avaliar a FG e fatores associados em hipertensos. Métodos: Realizou-se estudo transversal no período de janeiro a junho de 2008, com 297 hipertensos com ou sem diabete melito (DM) tratados em uma unidade básica de saúde em São Luís-MA. Foram incluídos pacientes >20 anos e de ambos os sexos. Avaliaram-se dados sociodemográficos, estado nutricional, FG e microalbuminúria em urina de 24h, controle pressórico e glicêmico, creatinina sérica e lipidograma. Resultados: A idade média foi 60,6 ± 11,5 anos com predomínio do sexo feminino (75,1%), sobrepeso/obesidade (65,0%) e circunferência da cintura elevada (60,6%). A prevalência de FG < 60 ml/min foi 24,6% no grupo HA sem DM e 18,3% no HA com DM, sem diferença significante. Para o grupo HA sem DM houve associação apenas da FG reduzida com idade > 65 anos, que permaneceu após ajustamento. Para o grupo HA com DM houve associação da redução da FG com idade > 65 anos, tabagismo e obesidade, porém, após ajustamento, permaneceram idade e tabagismo. Conclusão: Nestes pacientes, a prevalência de FG < 60 ml/min foi elevada e, após ajustamento, apenas idade > 65 anos e tabagismo apresentaram-se como fatores associados à FG. Isto reforça a necessidade da avaliação sistemática da FG em hipertensos visando a prevenção secundária da doença renal crônica. (Arq Bras Cardiol. 2010; [online]. ahead print, PP.0-0)Background: In Brazil, arterial hypertension (AH) constitutes one of the main risk factors for chronic kidney disease (CKD). The monitoring of glomerular filtration (GF) is recommended for the assessment of kidney function in hypertensive individuals, as GF decrease precedes symptom onset. Objective: To assess GF and its associated factors in hypertensive individuals. Methods: A cross-sectional study was carried out from January to June 2008 in 297 individuals with arterial hypertension (AH) with or without diabetes mellitus (DM), treated at a primary care facility in the city of São Luís, Maranhão. Patients older than 20 years and of both sexes were included in the study. Sociodemographic and nutritional status data, GF rate and microalbuminuria levels in 24-hour urine were assessed, as well as blood pressure, glucose and serum creatinine levels and a lipidogram. Results: Mean age was 60.6 ± 11.5 years, with a predominance of the female sex (75.1%), overweight/obesity (65.0%) and large waist circumference (60.6%). The prevalence of GF < 60 ml/min was 24.6% in the AH group without DM and 18.3% in the AH group with DM, with no significant difference. For the AH group without DM, there was an association only between reduced GF and age > 65 years, which remained after adjustment. For the AH group with DM, there was an association between reduced GF and age > 65 years, smoking habit and obesity. However, after the adjustment, age and smoking habit remained as associated factors. Conclusion: In these patients, the prevalence of GF < 60 ml/min was high and after the adjustment, only age > 65 years and smoking habit were shown to be factors associated to GF. This reinforces the need to systematically evaluate GF in hypertensive individuals, aiming at the secondary prevention of chronic kidney disease. (Arq Bras Cardiol. 2010; [online]. ahead print, PP.0-0