Details

Autor(en) / Beteiligte

• Díaz Enamorado, Yunayka
• Shabaka, Amir
• Dominguez Torres, Patricia
• Maria Cases Corona, Clara
• Landaluce Triska, Eugenia
• León-Póo, Mariana
• Maria Fernandez Juarez, Gema

Titel

MO377: Correlation Between 24-H Proteinuria and Spot Urine Albumin-Creatinine Ratio in Biopsy-Proven Glomerular Diseases

Ist Teil von

• Nephrology, dialysis, transplantation, 2022-05, Vol.37 (Supplement_3)

Erscheinungsjahr

2022

Quelle

Oxford Journals 2020 Medicine

Beschreibungen/Notizen

• Abstract BACKGROUND AND AIMS The gold standard for measurement of protein excretion is a 24-h urine collection. However, due to the cumbersome nature as well as the frequent errors in sample collection, it has been suggested that the measurement of albumin-creatinine ratio (ACR) in a spot urine sample could replace 24-h proteinuria as a valid method for the diagnosis and follow-up of renal disease, which is supported by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. The aim of our study was to assess the correlation between 24-h proteinuria and spot urine ACR in patients with biopsy-proven glomerulonephritis, METHOD We identified patients with biopsy-proven glomerular diseases who were evaluated during their disease course at our center between 1 January 2005 and 31 December 2021, and included patients with paired 24 h and spot urine samples simultaneously collected at the same day. We excluded patients with interstitial or vascular causes for kidney disease. We contrasted correlation of ACR and 24 h proteinuria according to demographic data, glomerular filtration rate measured at the day of urine collection, and type of glomerular disease. RESULTS A total of 977 paired 24-hr proteinuria and spot urine ACR samples were collected at the same day from 370 patients and included in this study. The mean age of the selected population was 52.1 ± 17.7 years, with a median serum creatinine of 1.26 mg/dL (IQR: 0.94–1.74) and mean eGFR measured by CKD-EPI of 62.4 ± 30.1 mL/min. Median 24-h proteinuria was 1.48 g/day (IQR: 0.59–3.39), and the median ACR was 539 mg/g (IQR: 131–1569). We found an excellent correlation between ACR and 24-h proteinuria (Spearman's r = 0.86, P < 0.001). This correlation was reproducible across all CKD stages, and remained strong even in patients with eGFR <30 mL/min/1.73 m2 (Spearman's r = 0.85, P < 0.001). On the other hand, after stratifying the cohort according to grade of proteinuria, we found that correlation was significantly weaker when proteinuria >3 g/day (Spearman's r = 0.50, P < 0.001) compared with lower grade proteinuria <3 g/day (r = 0.79, P < 0.001). We found no differences in correlation between ACR and 24-h proteinuria according to the type of glomerular disease, with excellent correlation across all glomerulonephritides.   ROC analysis showed that a ACR cutoff of >250 mg/g was the best predictor for 24-h proteinuria >1 g/day, with an area under the curve (AUC) of 0.933, sensitivity 91% and specificity 81%, while an ACR cutoff of >800 mg/g best predicted a 24-hour proteinuria of >3.5 g/day,  with an AUC of 0.922, sensitivity of 92% and specificity of 76%. CONCLUSION There is an excellent correlation between ACR and 24-h proteinuria in patients with proteinuria <3 g/day independent from eGFR and without significant variation according to the type of glomerular disease. In patients with proteinuria >3 g/day,  ACR correlates poorly with proteinuria. We suggest that patients with higher grade proteinuria should always be assessed with a 24-h urine sample protein excretion for therapeutic decisions and follow-up in glomerular diseases.