Proteinuria is still useful for the screening and diagnosis of overt diabetic nephropathy

• Autor(a) principal: Zelmanovitz, Themis
• Data de Publicação: 2022
• Outros Autores: L. Gross, Jorge, Oliveira, Jarbas, J. de Azevedo, Mirela
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Clinical and Biomedical Research
• Texto Completo: https://seer.ufrgs.br/index.php/hcpa/article/view/124652

OBJECTIVE: To assess the performance of urinary total protein measurements intimed 24-h urine collection and in a diurnal random urine specimen for the screeningand diagnosis of overt diabetic nephropathy.PATIENTS AND METHODS: A total of 167 diabetic patients (20 type 1 and 147 type2 diabetic patients; 78 women and 89 men), aged 20-84 years, collected 217 timed24-h urine specimens. Albumin was measured by immunoturbidimetry, total proteinby the sulfosalicylic acid technique, and creatinine by Jaffé’s method. According tothe timed 24-h urinary albumin excretion rate, samples were divided into three groups:normoalbuminuric (urinary albumin excretion rate < 20 mg/min; n = 84),microalbuminuric (urinary albumin excretion rate 20-200 mg/min; n = 78), andmacroalbuminuric (urinary albumin excretion rate > 200 mg/min; n = 55). Eight-sixpatients also collected 105 random urine specimens (normoalbuminuric, n = 47;microalbuminuric, n = 37; macroalbuminuric, n = 21), and urinary protein concentrationand urinary protein-to-creatinine ratio were measured. The receiver operatingcharacteristics curve approach was used to analyze the performance of the diagnostictests.RESULTS: Spearman’s coefficient of correlation of 24-h urinary albumin excretionrate versus 24-h urinary protein was 0.95 ( P < 0.001), and of 24-h urinary albuminexcretion rate versus urinary protein concentration and urinary protein-to-creatinineratio were 0.77 and 0.72, respectively (P < 0.001). The calculated areas (±SEM)under the receiver operating characteristics curve for the diagnosis of overt diabeticnephropathy were 0.9987 ± 0.001 for 24-h urinary protein, 0.9926 ± 0.006 for urinaryprotein concentration, and 0.9751 ± 0.014 for urinary protein-to-creatinine ratio. Inthe receiver operating characteristics curves, the first points with 100% sensivitywere 541 mg (95.7% specificity) for 24-h urinary protein, 431 mg/l (92.9% specificity)for urinary protein concentration, and 0.2 (76.2% specificity) for urinary protein-tocreatinine ratio.CONCLUSIONS: Measurements of proteinuria presented almost perfect accuracyfor the screening and diagnosis of overt diabetic nephropathy. Protein measurementin spot urine is a reliable and simple method for the screening and diagnosis of overtdiabetic nephropathy.