Correlation between urine ACR and 24-h proteinuria in a real-world cohort of systemic AL amyloidosis patients

Alissa Visram, Abdullah S. Al Saleh, Harsh Parmar, Jennifer S. McDonald, John C. Lieske, Iuliana Vaxman, Eli Muchtar, Miriam Hobbs, Amie Fonder, Yi L. Hwa, Francis K. Buadi, David Dingli, Martha Q. Lacy, Angela Dispenzieri, Prashant Kapoor, Suzanne R. Hayman, Rahma Warsame, Taxiarchis V. Kourelis, Mustaqeem Siddiqui, Wilson I. GonsalvesJohn A. Lust, Robert A. Kyle, S. Vincent Rajkumar, Morie A. Gertz, Shaji K. Kumar, Nelson Leung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

A 24-h urine protein collection (24hUP), the gold standard for measuring albuminuria in systemic AL amyloidosis, is cumbersome and inaccurate. We retrospectively reviewed 575 patients with systemic AL amyloidosis to assess the correlation between a urine albumin to creatinine ratio (uACR) and the 24hUP. The uACR correlated strongly with 24hUP at diagnosis (Pearson’s r = 0.87, 95% CI 0.83–0.90) and during the disease course (Pearson’s r = 0.88, 95% CI 0.86–0.90). A uACR ≥300 mg/g estimated a 24hUP ≥ 500 mg with a sensitivity of 92% and specificity of 97% (area under the receiver operating curve = 0.938, 95% CI 0.919–0.957). A uACR cutoff of 3600 mg/g best predicted a 24hUP > 5000 g (sensitivity 93%, specificity 94%), and renal stage at diagnosis was strongly concordant using either 24hUP or uACR as the proteinuria measure (k = 0.823, 95% CI 0.728–0.919). In patients with serial urine collections, a > 30% decrease in uACR predicted a > 30% decrease in 24hUP with a sensitivity of 94%. In conclusion, the uACR is a reliable and convenient method for ruling out proteinuria >500 mg per day, prognosticating renal outcomes, and assessing renal response to therapy. Further studies are needed to validate the uACR cutoffs proposed in this study.

Original languageEnglish
Article number124
JournalBlood Cancer Journal
Volume10
Issue number12
DOIs
StatePublished - Dec 2020

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