Faculty Collaboration Database

Incidence and Importance of Calcium Deposition in Kidney Biopsy Specimens. Am J Nephrol 2022;53(7):526-533

Date

07/25/2022

Pubmed ID

35871513

Pubmed Central ID

PMC10503271

DOI

10.1159/000525647

Scopus ID

2-s2.0-85135764404 (requires institutional sign-in at Scopus site)

Abstract

INTRODUCTION: Calcification on native kidney biopsy specimens is often noted by pathologists, but the consequence is unknown.

METHODS: We searched the pathology reports in the Biopsy Biobank Cohort of Indiana for native biopsy specimens with calcification.

RESULTS: Of the 4,364 specimens, 416 (9.8%) had calcification. We compared clinical and histopathology findings in those with calcification (n = 429) compared to those without calcification (n = 3,936). Patients with calcification were older, had more comorbidities, lower estimated glomerular filtration rates (eGFR), were more likely to have hyaline arteriosclerosis, interstitial fibrosis/tubular atrophy, and a primary pathologic diagnosis of acute tubular injury or acute tubular necrosis when compared to patients without calcification. Patients with calcium oxalate deposition alone, compared to calcium phosphate or mixed calcifications, had fewer comorbidities but were more likely to have a history of gastric bypass surgery or malabsorption and take vitamin D. In patients with two or more years of follow-up, multivariate analyses showed the presence of calcification (HR 0.59, 0.38-0.92, p = 0.02) and higher eGFR (HR 0.76, 0.73-0.79, p < 0.001), was associated with decreased likelihood of progressing to end-stage renal disease. The presence of calcification was also associated with a reduced slope/decline in eGFR compared to known biopsy and clinical risk factors for decline in kidney function. We hypothesized this was due to more recoverable acute kidney injury (AKI) and found more severe acute kidney injury network stage in patients with kidney calcification but also greater improvement over time.

DISCUSSION/CONCLUSION: In summary, we demonstrated that calcification on kidney biopsy specimens was associated with a better prognosis than those without calcification due to the association with recoverable AKI.

Author List

Gaddy A, Schwantes-An TH, Moorthi RN, Phillips CL, Eadon MT, Moe SM

Author

Anna Gaddy MD Assistant Professor in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Acute Kidney Injury
Biopsy
Calcium
Glomerular Filtration Rate
Humans
Incidence
Kidney
Retrospective Studies