AUTHOR=Muchtar Eli , Drake Matthew T. , Leung Nelson , Dispenzieri Angela , Lacy Martha Q. , Buadi Francis K. , Dingli David , Hayman Suzanne R. , Kapoor Prashant , Hwa Yi Lisa , Fonder Amie , Hobbs Miriam , Gonsalves Wilson , Kourelis Taxiarchis V. , Warsame Rahma , Russell Stephen , Go Ronald S. , Binder Moritz , Kyle Robert A. , Rajkumar S. Vincent , Kumar Shaji K. , Gertz Morie A. 

TITLE=Hypovitaminosis D Is Prevalent in Patients With Renal AL Amyloidosis and Associated With Renal Outcome

JOURNAL=Frontiers in Endocrinology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2022.891712

DOI=10.3389/fendo.2022.891712

ISSN=1664-2392

ABSTRACT=<sec><title>Introduction</title><p>Vitamin D deficiency is common, but no data have been reported on vitamin D levels in light chain (AL) amyloidosis.</p></sec><sec><title>Patients and Methods</title><p>In this exploratory study, stored serum samples from 173 patients with newly diagnosed AL amyloidosis were analyzed for vitamin studies which included 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)<sub>2</sub>D] and vitamin D binding protein (DBP). Measurements were made by liquid chromatography-tandem mass spectrometry. Kidney survival and overall survival (OS) were assessed in association to vitamin D status.</p></sec><sec><title>Results</title><p>Cardiac and kidney involvement occurred in 69% and 63% of patients, respectively. 25(OH)D deficiency (&lt;20 ng/mL) was seen in 56.6% of the patients and was notably found among patients with heavy proteinuria (96%), hypoalbuminemia (84.3%) and morbidly obese patients (68.3%). Heavy proteinuria (&gt;5 gr/24-h) and vitamin D supplementation were independent predictors of 25(OH)D level on nominal multivariate regression analysis. 1,25(0H)<sub>2</sub>D deficiency was noted in 37.6% of patients and was independently associated with low eGFR and hypoalbuminemia. Progression to ESRD occurred in 23.7% of evaluable patients. Patients who progressed to ESRD had lower serum 25(OH)D and 1,25(OH)<sub>2</sub>D levels compared to those who did not progress to ESRD. On a multivariate analysis, severe 25(OH)D deficiency was an independent predictor of progression to ESRD as was renal stage, while 1,25(OH)<sub>2</sub>D deficiency was not.</p></sec><sec><title>Conclusions</title><p>Hypovitaminosis D is common in AL amyloidosis, particularly among patients with heavy proteinuria. Severe 25(OH)D deficiency at time of diagnosis predicts progression to ESRD.</p></sec>