RESUMO
BACKGROUND: Low birth weight caused by intrauterine growth restriction may be a risk factor for renal impairment in the adult life. STUDY DESIGN: A cross-sectional study. SETTING & PARTICIPANTS: 71 children aged 8 to 13 years living in the community of São Paulo, Brazil, were included in the study. Gestational age was within the normal range. PREDICTORS: Birth weight (range, 2,052 to 3,560 g) divided into quartiles: 2,500 g or less; 2,501 to 2,740 g; 2,741 to 3,000 g; and greater than 3,000 g. Birth weight ascertained by birth records in 43 and by recall in 28 participants. OUTCOMES & MEASUREMENTS: Cystatin C, creatinine, and glomerular filtration rate (GFR) estimated by equations using cystatin C (eGFR(cys)) or creatinine (eGFR(cr)). RESULTS: Overall, mean serum creatinine level was 0.8 +/- 0.01 (SE) mg/dL (range, 0.7 to 1.1 mg/dL); mean plasma cystatin C level was 0.9 +/- 0.02 mg/L (range, 0.5 to 1.6 mg/L), and eGFR(cr) and eGFR(cys) were 102.4 +/- 2.16 (range, 66 to 140) and 91.8 +/- 2.46 mL/min/1.73 m(2) (range, 49 to 139 mL/min/1.73 m(2)), respectively. No differences were found for serum creatinine or eGFR(cr) values among the birth-weight quartiles. There was a significant linear trend of increasing cystatin C levels (decreasing eGFR(cys)) in the lower birth-weight quartile groups (P = 0.002 and P = 0.02, respectively). Systolic blood pressure correlated with plasma cystatin C level (r = 0.31; P = 0.008) and eGFR(cys) (r = -0.26; P = 0.028). Covariance analysis adjusting for age, sex, body mass index for age compared with standards of the National Center for Health Statistics and expressed as a z score, and systolic blood pressure showed that cystatin C values remained greater in the lowest than highest birth-weight quartile (1.01 +/- 0.05 versus 0.83 +/- 0.05 mg/L; P = 0.02). LIMITATIONS: Ascertainment of birth weight by recall in some participants. Lack of measurement of microalbuminuria, absence of direct GFR measurement, and small sample size. CONCLUSIONS: Lower birth weight is associated with higher levels of cystatin C but not creatinine in 8-13 yr. old children born full-term.
Assuntos
Creatinina/sangue , Cistatinas/sangue , Taxa de Filtração Glomerular , Recém-Nascido Pequeno para a Idade Gestacional , Adolescente , Criança , Estudos Transversais , Cistatina C , Feminino , Humanos , Recém-Nascido , MasculinoRESUMO
BACKGROUND: To compare estimated glomerular filtration rate (GFR) by Schwartz formula and cystatin C-derived formula in a large population of children with a large spectrum of renal disease. METHODS: Serum creatinine, cystatin C and estimated GFR were determined in 273 children, 254 with renal disease, and a mean age of 10.0+/-4.4 y. Nineteen children were used as control, with a mean age of 8.5+/-4.2 y. RESULTS: The children had nephrotic syndrome (16.5%), glomerulonephritis (11.4%), neurogenic bladder (11.4%), hydronephrosis (9.8%), asymptomatic hematuria (11%), chronic renal disease (5.9%) and other diseases (11%). Cystatin C, creatinine, Schwartz estimated GFR and cystatin C estimated GFR (mean+/-SD) were 1.30+/-1.03 mg/dl, 0.82+/-1.20 mg/l, 143+/-72 ml/min/1.73 m(2) and 88+/-36 ml/min/1.73 m(2), respectively. Although GFR estimated by creatinine and cystatin C had a significant correlation, the Bland-Altman analysis showed greater differences between GFR estimated by the 2 methods, with a mean difference of 50 ml/min. Besides, >50% of the patients with a reduced cystatin C estimated GFR had a normal GFR when analyzed by the Schwartz formula. CONCLUSIONS: Our data shows that cystatin C-based GFR is more sensitive than previous study had demonstrated. It is important to perform studies in specific populations to determine the variability in GFR measurements.
Assuntos
Creatinina/sangue , Cistatinas/sangue , Taxa de Filtração Glomerular , Nefropatias/diagnóstico , Insuficiência Renal/diagnóstico , Adolescente , Estatura , Peso Corporal , Criança , Pré-Escolar , Cistatina C , Feminino , Humanos , Nefropatias/sangue , Nefropatias/fisiopatologia , Testes de Função Renal , Masculino , Insuficiência Renal/sangue , Insuficiência Renal/fisiopatologiaRESUMO
BACKGROUND AND OBJECTIVES: For addressing the influence of muscle mass on serum and urinary creatinine and serum cystatin C, body composition was assessed by skinfold thickness measurement and bioelectrical impedance analyses. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A total of 170 healthy individuals (92 women, 78 men) were classified as sedentary or with mild or moderate/intense physical activity. Blood, 24-h urine samples, and 24-h food recall were obtained from all individuals. RESULTS: Serum and urinary creatinine correlated significantly with body weight, but the level of correlation with lean mass was even greater. There was no significant correlation between body weight and lean mass with cystatin C. Individuals with moderate/intense physical activity presented significantly lower mean body mass index (23.1 +/- 2.5 versus 25.7 +/- 3.9 kg/m(2)) and higher lean mass (55.3 +/- 10.0 versus 48.5 +/- 10.4%), serum creatinine (1.04 +/- 0.12 versus 0.95 +/- 0.17 mg/dl), urinary creatinine (1437 +/- 471 versus 1231 +/- 430 mg/24 h), protein intake (1.4 +/- 0.6 versus 1.1 +/- 0.6 g/kg per d), and meat intake (0.7 +/- 0.3 versus 0.5 +/- 0.4 g/kg per d) than the sedentary individuals. Conversely, mean serum cystatin did not differ between these two groups. A multivariate analysis of covariance showed that lean mass was significantly related to serum and urinary creatinine but not with cystatin, even after adjustment for protein/meat intake and physical activity. CONCLUSIONS: Cystatin C may represent a more adequate alternative to assess renal function in individuals with higher muscle mass when mild kidney impairment is suspected.
Assuntos
Creatinina/sangue , Creatinina/urina , Cistatinas/sangue , Atividade Motora , Músculo Esquelético , Adolescente , Adulto , Idoso , Cistatina C , Impedância Elétrica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dobras CutâneasRESUMO
BACKGROUND: Chronic kidney disease (CKD) is a worldwide public health problem. Glomerular filtration rate (GFR) is accepted as the best way to diagnose and monitor kidney function. Plasma Cystatin C (CysC) has been proposed as a better marker of GFR than serum creatinine (SCr), but it is not widely used because of some drawbacks with CysC assays. Our purpose is to determine the diagnostic accuracy of CysC and SCr for GFR estimation in children, using 99Tc-DTPA clearance (Cl(Tc)) as the reference standard. We also discuss some of the economic implications of these tests, in order to guide clinicians when to use CysC or SCr for the diagnosis or monitoring of CKD. METHODS: Data were collected from 109 Colombian outpatients aged less than 18 years referred for determination of GFR because of suspected or definite renal insufficiency. The cost of each test was determined in Bogotá, Colombia, and in Madrid, Spain. RESULTS: Using a GFR of 90 mL/min as a cut-off value, we found: CysC sensitivity 75%, specificity 84%, and area under ROC curve (AUC) 0.84. SCr sensitivity 46%, specificity 100%, and AUC 0.72. Using a GFR of 70 mL/min as a cut-off value, we found: CysC sensitivity 100%, specificity 48%, and AUC 0.94. SCr sensitivity 77%, specificity 91%, and AUC 0.81. In all calculations predictive values behave correspondingly and ranges were narrow at CI 95%. In AUC, p=0.0001. Cost per enzymatic test in Bogotá: CysC U$ 27; SCr U$ 2. Cost per enzymatic test in Madrid: CysC U$ 3; SCr U$ 0.08. CONCLUSION: CysC is a very interesting option, and could be a replacement to serum creatinine for diagnosing and possibly for monitoring kidney function in children.
Assuntos
Creatinina/sangue , Cistatinas/sangue , Testes de Função Renal/métodos , Adolescente , Biomarcadores/sangue , Criança , Pré-Escolar , Cistatina C , Feminino , Taxa de Filtração Glomerular/fisiologia , Humanos , Lactente , Nefropatias/sangue , Nefropatias/diagnóstico , Nefropatias/fisiopatologia , Testes de Função Renal/tendências , Masculino , Monitorização Fisiológica , Estudos ProspectivosRESUMO
Serum creatinine is an insensitive marker to identify early changes in glomerular filtration rate (GFR), for this reason alternative methods to estimate renal function result of great clinical importance. Forty-one patients were studied using creatinine clearance modified with cimetidina (Clcrc) as surrogate of GFR, cystatin C-based equations (i.e. Larsson and Hoek formulas), Cockroft-Gault and MDRD abbreviated equations. In the whole group, as well as in those patients with serum creatinine < or =1.2 mg/dl--but reduced renal function: Clcrc 62.01 +/- 17.33 ml/ min/1.73 m(2)-, Larsson and Hoek equations showed higher correlations and lower bias than creatinine-based formulas. Abbreviated MDRD equation showed good performance just in those patients with evident alteration of renal function (serum creatinine > 1.2 mg/dl). We concluded that in patients with different stages of renal function, cystatin C-based equations detect reduction of renal function earlier than the serum creatinine-based formulas.
Assuntos
Creatinina/sangue , Cistatinas/sangue , Taxa de Filtração Glomerular/fisiologia , Testes de Função Renal , Biomarcadores/sangue , Cimetidina/administração & dosagem , Creatinina/antagonistas & inibidores , Cistatina C , Cistatinas/antagonistas & inibidores , Interpretação Estatística de Dados , Inibidores Enzimáticos/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: To analyze systemically the prevalence of renal involvement in a cohort of Finnish patients with lysinuric protein intolerance (LPI) and to describe the course and outcome of end-stage renal disease in 4 patients. STUDY DESIGN: The clinical information in a cohort of 39 Finnish patients with LPI was analyzed retrospectively. RESULTS: Proteinuria was observed in 74% of the patients and hematuria was observed in 38% of the patients during follow-up. Elevated blood pressure was diagnosed in 36% of the patients. Mean serum creatinine concentration increased in 38% of the patients, and cystatin C concentration increased in 59% of the patients. Four patients required dialysis, and severe anemia with poor response to erythropoietin and iron supplementation also developed in these patients. CONCLUSIONS: Our findings suggest that renal function of patients with LPI needs to be carefully monitored, and hypertension and hyperlipidemia should be treated effectively. Special attention also should be paid to the prevention of osteoporosis and carnitine deficiency in the patients with end-stage renal disease associated with LPI. The primary disease does not prohibit treatment by dialysis and renal transplantation.
Assuntos
Transtornos Congênitos do Transporte de Aminoácidos/complicações , Nefropatias/etiologia , Falência Renal Crônica/etiologia , Lisina/urina , Adolescente , Adulto , Criança , Pré-Escolar , Citrulina/sangue , Creatinina/sangue , Cistatina C , Cistatinas/sangue , Progressão da Doença , Feminino , Taxa de Filtração Glomerular , Humanos , Lactente , Nefropatias/sangue , Nefropatias/patologia , Falência Renal Crônica/cirurgia , Transplante de Rim , Masculino , Pessoa de Meia-Idade , Proteinúria/etiologiaRESUMO
La creatinina sérica es un marcador poco sensible para identificar reducciones leves del índice de filtración glomerular (IFG); por ello resulta de gran importancia clínica disponer de métodos alternativos para estimar la función renal. Con este objetivo estudiamos la función renal de 41 pacientes -grupo completo y divididos según la creatinina sérica (menor o igual 1.2 mg/dl o mayores)- usando el clearance de creatinina modificado con cimetidina (Clcrc) como aproximación al IFG, las ecuaciones de Larsson y Hoek que incluyen el uso de cistatina C sérica y las tradicionales fórmulas de Cockroft-Gault y MDRD abreviada. En el grupo completo de pacientes y especialmente en aquellos con creatinina sérica menor o igual 1.2 mg/dl - con reducción de la función renal: Clcrc: 62.01 mas o menos 17.33 ml/min/1.73 m2-, las ecuaciones de Larsson y Hoek mostraron mejores correlaciones y menores diferencias promedio respecto a las fórmulas basadas en la creatinina sérica. La ecuación MDRD abreviada mostró buen rendimiento sólo en el grupo con evidente alteración de la función renal (creatinina sérica > 1.2 mg/dl). Concluimos que en pacientes con diferentes estadios de función renal, las fórmulas que emplean la cistatina C sérica detectan la reducción del IFG más precozmente respecto a aquellas basadas en la creatinina sérica.
Serum creatinine is an insensitive marker to identify early changes in glomerular filtration rate (GFR), for this reason alternative methods to estimate renal function result of great clinical importance. Forty-one patients were studied using creatinine clearance modified with cimetidina (Clcrc) as surrogate of GFR, cystatin C-based equations (i.e. Larsson and Hoek formulas), Cockroft-Gault and MDRD abbreviated equations. In the whole group, as well as in those patients with serum creatinine less than or equal to 1.2 mg/dl -but reduced renal function: Clcrc 62.01 more or less 17.33 ml/min/1.73 m2-, Larsson and Hoek equations showed higher correlations and lower bias than creatinine-based formulas. Abbreviated MDRD equation showed good performance just in those patients with evident alteration of renal function (serum creatinine > 1.2 mg/dl). We concluded that in patients with different stages of renal function, cystatin C-based equations detect reduction of renal function earlier than the serum creatinine-based formulas.
Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Creatinina/sangue , Cistatinas/sangue , Taxa de Filtração Glomerular/fisiologia , Testes de Função Renal , Biomarcadores/sangue , Cimetidina/administração & dosagem , Creatinina/antagonistas & inibidores , Cistatinas/antagonistas & inibidores , Interpretação Estatística de Dados , Inibidores Enzimáticos/administração & dosagem , Modelos Teóricos , Sensibilidade e EspecificidadeRESUMO
La creatinina sérica es un marcador poco sensible para identificar reducciones leves del índice de filtración glomerular (IFG); por ello resulta de gran importancia clínica disponer de métodos alternativos para estimar la función renal. Con este objetivo estudiamos la función renal de 41 pacientes -grupo completo y divididos según la creatinina sérica (menor o igual 1.2 mg/dl o mayores)- usando el clearance de creatinina modificado con cimetidina (Clcrc) como aproximación al IFG, las ecuaciones de Larsson y Hoek que incluyen el uso de cistatina C sérica y las tradicionales fórmulas de Cockroft-Gault y MDRD abreviada. En el grupo completo de pacientes y especialmente en aquellos con creatinina sérica menor o igual 1.2 mg/dl - con reducción de la función renal: Clcrc: 62.01 mas o menos 17.33 ml/min/1.73 m2-, las ecuaciones de Larsson y Hoek mostraron mejores correlaciones y menores diferencias promedio respecto a las fórmulas basadas en la creatinina sérica. La ecuación MDRD abreviada mostró buen rendimiento sólo en el grupo con evidente alteración de la función renal (creatinina sérica > 1.2 mg/dl). Concluimos que en pacientes con diferentes estadios de función renal, las fórmulas que emplean la cistatina C sérica detectan la reducción del IFG más precozmente respecto a aquellas basadas en la creatinina sérica.(AU)
Serum creatinine is an insensitive marker to identify early changes in glomerular filtration rate (GFR), for this reason alternative methods to estimate renal function result of great clinical importance. Forty-one patients were studied using creatinine clearance modified with cimetidina (Clcrc) as surrogate of GFR, cystatin C-based equations (i.e. Larsson and Hoek formulas), Cockroft-Gault and MDRD abbreviated equations. In the whole group, as well as in those patients with serum creatinine less than or equal to 1.2 mg/dl -but reduced renal function: Clcrc 62.01 more or less 17.33 ml/min/1.73 m2-, Larsson and Hoek equations showed higher correlations and lower bias than creatinine-based formulas. Abbreviated MDRD equation showed good performance just in those patients with evident alteration of renal function (serum creatinine > 1.2 mg/dl). We concluded that in patients with different stages of renal function, cystatin C-based equations detect reduction of renal function earlier than the serum creatinine-based formulas.(AU)