Ana Karina Teixeira da Cunha França

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.

Cystatin C, kidney function, and cardiovascular risk factors in primary hypertension*

OBJECTIVE To investigate the clinical usefulness of serum cystatin C (Scys) and cystatin C-based equations for the screening of chronic kidney disease in primary hypertensive patients, and correlate these markers with risk factors for cardiovascular disease. METHODS A cross-sectional study was performed in 199 middle-aged adults at a basic health unit. Kidney function assessment included measurements of serum creatinine (Scr) and Scys levels, 24-hour microalbuminuria (MA), as well as glomerular filtration rate (GFR) through Larsson and Modification of Diet in Renal Disease (MDRD) study equations. Bland- Altman plot analysis was used to calculate the agreement between equations. RESULTS High levels of Scys were found in 22% of the patients, even with normal values of GFR estimated by MDRD study equation. Systolic blood pressure and MA correlated better with Scys than Scr, but there was no correlation between Scys and diastolic blood pressure. Gender, age > 60 years, MA, and uric acid were significantly associated with high Scys levels. After multivariate analysis, only age > 60 yrs (RR = 6.4; p < 0.001) and male gender (RR = 3.0; p = 0.006) remained associated with high Scys levels. CONCLUSION Cystatin C can be used as a screening marker both for detecting mild declines of renal function and for preventing the risk of cardiovascular events in hypertensive subjects with presumably normal renal function.

Dietary approach to hypertension based on low glycaemic index and principles of DASH (Dietary Approaches to Stop Hypertension): a randomised trial in a primary care service

Hypertension is one of the leading causes of morbidity and mortality in Brazil. Diet may play an important role in reducing blood pressure (BP), as has been shown for diets high in fruits, vegetables and low-fat dairy products and low in salt (Dietary Approaches to Stop Hypertension (DASH)-Na). A low-glycaemic index Brazilian diet combined with the principles of the DASH-Na diet was evaluated in a randomised study of 206 individuals who were followed for 6 months. In the control group (CG), counselling was based on standard care and mainly focused on salt intake reduction. An intention-to-treat analysis showed that, after 6 months, systolic BP was reduced by 14·4 mmHg and diastolic BP by 9·7 mmHg in the experimental group (EG), compared with 6·7 and 4·6 mmHg, respectively, in the CG. After adjusting for body weight, BP at baseline and age, these changes were 12·1 and 7·9 mmHg, respectively. Urinary Na excretion was also reduced by 43·4 mEq/24 h in the EG. Food intake was modified accordingly during the intervention with an increase in the consumption of vegetables (2·97-5·85 frequency of consumption measured in three non-consecutive days), fruits (4·09-7·18), beans (1·94-3·13) and fish (1·80-2·74) by the EG. The present study showed the feasibility of a Brazilian dietary approach to treating hypertension by reducing urinary Na excretion and BP, changes that may have a great impact on public health and promote the benefits of controlling hypertension.

Estimated Visceral Adipose Tissue, but Not Body Mass Index, Is Associated with Reductions in Glomerular Filtration Rate Based on Cystatin C in the Early Stages of Chronic Kidney Disease

Information on the association between obesity and initial phases of chronic kidney disease (CKD) is still limited, principally those regarding the influence of visceral adipose tissue. We investigated whether the visceral adipose tissue is more associated with reductions in glomerular filtration rate (GFR) than total and abdominal obesity in hypertensive individuals with stage 1-2 CKD. A cross-sectional study was implemented which involved 241 hypertensive patients undergoing treatment at a primary health care facility. GFR was estimated using equations based on creatinine and cystatin C levels. Explanatory variables included body mass index (BMI), waist circumference (WC), and estimated visceral adipose tissue (eVAT). The mean age was 59.6 ± 9.2 years old and 75.9% were female. According to BMI, 28.2% of subjects were obese. Prevalence of increased WC and eVAT was 63.9% and 58.5%, respectively. Results from the assessment of GFR by BMI, WC, and eVAT categories showed that only women with increased eVAT (≥150 cm2) had a lower mean GFR by Larsson (P = 0.016), Levey 2 (P = 0.005), and Levey 3 (P = 0.008) equations. The same result was not observed when the MDRD equation was employed. No association was found between BMI, WC, eVAT, and GFR using only serum creatinine. In the early stages of CKD, increased eVAT in hypertensive women was associated with decreased GFR based on cystatin C.

Cintura hipertrigliceridêmica e risco cardiometabólico em mulheres hipertensas

OBJECTIVE: To evaluate the association between hypertriglyceridemic waist (HW) and cardiometabolic risk factors in women with hypertension. METHODS: A cross-sectional study was performed in 218 patients monitored by HiperDia (Enrollment and Monitoring Program for Hypertensive and Diabetic Individuals) in two health units in Sao Luis, MA, Brazil. The dependent variable was HW and the independent variables were sociodemographics, lifestyle, anthropometrics, and health problems. RESULTS: HW was present in 33% of the sample and was predominant in women aged > 60 years (56.4%), non-whites (81.7%), those with eight or fewer years of schooling (57.3%), and those belonging to socioeconomic class C (49%). Excess weight (68.8%) and hypercholesterolemia (68.8%) were observed. HW was associated with: smoking (PR: 2.08; p = 0.017), overweight (PR: 2.46; p = 0.010), obesity (PR: 4.13; p 100 mg/dL or being diabetic (PR: 1.86; p = 0.006). After adjustment, total cholesterol (PR = 1.78; p = 0.012), HDL-cholesterol (PR: 3.03; p 25 to 30 kg/m2 (PR = 3.61; p < 0.001) remained associated. CONCLUSION: A high prevalence of HW and its association with altered lipid profile and excess body weight was observed. HW showed to be an important diagnostic tool for the monitoring of hypertensive women with metabolic risk, which is low cost, easily accessible, and useful in clinical practice, especially in primary health care in the Brazilian Unified Health System (Sistema Unico de Saude - SUS).

Filtração glomerular e fatores associados em hipertensos atendidos na atenção básica

FUNDAMENTO: No Brasil, a hipertensao arterial (HA) constitui-se um dos principais fatores de risco para doenca renal cronica (DRC). Recomenda-se o monitoramento da filtracao glomerular (FG) para avaliacao da funcao renal em hipertensos, posto que sua reducao precede o aparecimento de sintomas. OBJETIVO: Avaliar a FG e fatores associados em hipertensos. METODOS: Realizou-se estudo transversal no periodo de janeiro a junho de 2008, com 297 hipertensos com ou sem diabete melito (DM) tratados em uma unidade basica de saude em Sao Luis-MA. Foram incluidos pacientes >20 anos e de ambos os sexos. Avaliaram-se dados sociodemograficos, estado nutricional, FG e microalbuminuria em urina de 24h, controle pressorico e glicemico, creatinina serica e lipidograma. RESULTADOS: A idade media foi 60,6 × 11,5 anos com predominio do sexo feminino (75,1%), sobrepeso/obesidade (65,0%) e circunferencia da cintura elevada (60,6%). A prevalencia de FG 65 anos, que permaneceu apos ajustamento. Para o grupo HA com DM houve associacao da reducao da FG com idade > 65 anos, tabagismo e obesidade, porem, apos ajustamento, permaneceram idade e tabagismo. CONCLUSAO: Nestes pacientes, a prevalencia de FG 65 anos e tabagismo apresentaram-se como fatores associados a FG. Isto reforca a necessidade da avaliacao sistematica da FG em hipertensos visando a prevencao secundaria da doenca renal cronica.

Nutritional diagnosis of patients undergoing haemodialysis in the city of São Luís (MA), Brazil

OBJECTIVE: The objective was to evaluate the nutritional status of patients undergoing hemodialysis in Sao Luis (MA). METHODS: A total of 399 patients (mean age 49.6 years; standard deviation 15.6; 248 males) were assessed from three dialysis centers in the city. The inclusion criteria were the following: age 18 years or older, undergoing hemodialysis at least three times per week for at least the last three months, and not having any wasting diseases. The following data were collected to assess nutritional status: body mass index, mid-arm muscle circumference, triceps skinfold thickness, percentage of body fat (%BF), serum albumin, creatinine and total cholesterol, and subjective global assessment. RESULTS: Most patients were within the normal weight range according to body mass index (62.5%) and percentage of body fat (54.9%). Meanwhile, most were malnourished according to the mid-arm muscle circumference (63.0%) and triceps skinfold thickness (63.0%). According to the mid-arm muscle circumference, malnutrition was more prevalent in men (75.9%), whereas according to the triceps skinfold thickness, malnutrition was more prevalent in women (72.7%). Serum albumin values were below 4.0 g/dL in 67% of the studied patients. Serum creatinine levels were as expected for the population of the study as a whole; meanwhile, the cholesterol levels were near the lower end of the normal range. Malnutrition was found in 61% of the patients according to the subjective global assessment. CONCLUSION: The majority of the patients were classified as malnourished when criteria such as mid-arm muscle circumference, triceps skinfold thickness, subjective global assessment and serum albumin levels were considered, and in nutritional risk when serum creatinine and total cholesterol levels were considered. These data show that measures are necessary to improve the nutritional status of this population.

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.

Reductions in glycemic and lipid profiles in hypertensive patients undergoing the Brazilian Dietary Approach to Break Hypertension: a randomized clinical trial ☆,☆☆

Hypertensive patients often have an unfavorable lipid and glucose profile. The main goal of dietary treatment for these patients is to achieve adequate control of blood pressure and reducing cardiovascular morbidity and mortality. The aim of this study was to evaluate whether the Brazilian Dietary Approach to Break Hypertension (BRADA) based on Dietary Approaches to Stop Hypertension but with both low sodium and glycemic index foods could reduce lipid and glycemic profiles in hypertensive patients who were seeing primary health care providers in a low-income region of Brazil. A randomized study of 206 individuals were followed up for the duration of 6 months. The experimental group received orientation and planned monthly menus from the BRADA diet. In the control group, counseling was based on standard care and mainly focused on salt intake reduction. Differences in all biochemical parameters were compared at the baseline and at the 6-month follow-up period. The mean age was 60.1 (±12.9) years old, and 156 subjects (119 females) completed the study. An intention-to-treat analysis showed that both groups reduced fasting plasma glucose, glycated hemoglobin, total cholesterol, and low-density lipoprotein cholesterol concentrations; however, statistically significant between-group differences were found for these parameters. The mean difference in fasting glucose was -7.0 (P < .01), -0.2 for HbA1c (P < .01), -28.6 for TC (P < .01), and -23.8 for LDL-c (P < .01) for the experimental group compared with the control group. This study showed the efficacy of the BRADA diet to treat hypertension on biochemical parameters tested in a primary health care service setting.

Nutrient intake variability and the number of days needed to estimate usual intake in children aged 13–32 months

The number of days of data required to accurately estimate usual nutrient intake of children is not well established. This study aims to calculate the variability and the number of days required to estimate usual nutrient intake in children aged 13-32 months. This cross-sectional study, which is part of the BRISA Project in São Luís, Maranhão, Brazil, involved 231 children from April 2011 to January 2013. Socio-economic and demographic data were collected using a questionnaire, and 3 non-consecutive days of food consumption were collected using a 24-h dietary recall (24HDR) survey. Intrapersonal and interpersonal variability and variance ratio (VR) were obtained for each nutrient using the Multiple Source Method® program (version 1.0.1). The number of days (d) needed was calculated using the formula proposed by Black et al. for different correlation coefficients (r) (i.e. 0·7, 0·8 or 0·9). For the vast majority of nutrients, intrapersonal and interpersonal variability values of <1 were observed, with even smaller intrapersonal variabilities, resulting in low VR (<1). More days were needed to estimate intakes of soluble fibre (12), insoluble fibre (11), total fibre (10), vitamin C (9) and PUFA (7), while fewer days were needed for energy, carbohydrate, SFA, Ca, Fe, P and Zn (all had 2 d for r 0·9). However, most nutrients required one, two or three 24HDR for r 0·7, 0·8 or 0·9.