Risk factors and implications associated with renal mineralization in chronic kidney disease in cats

Tang, PK; Jepson, RE; Chang, YM; Geddes, RF; Hopkinson, M; Elliott, J

Abstract

Background
Nephrocalcinosis is a pathological feature of chronic kidney disease (CKD). Its pathophysiological implications for cats with CKD are unexplored.

Objectives
Identify nephrocalcinosis risk factors and evaluate its influence on CKD progression and all-cause mortality.

Animals
Fifty-one euthyroid client-owned cats with International Renal Interest Society (IRIS) stages 2-3 azotemic CKD.

Methods
Retrospective cohort study. Histopathological kidney sections were assessed for nephrocalcinosis (von Kossa stain). Nephrocalcinosis severity was determined by image analysis (ImageJ). Ordinal logistic regressions were performed to identify nephrocalcinosis risk factors. The influence of nephrocalcinosis on CKD progression and mortality risk were assessed using linear mixed model and Cox regression, respectively. Cats were categorized by their owner-reported time-averaged phosphate-restricted diet (PRD) intake, where PRD comprised ≥50%, 10-50%, or none of food intake.

Results
Nephrocalcinosis was rated as mild-to-severe in 78.4% and absent-to-minimal in 21.6% of cases. Higher baseline plasma total calcium concentration (tCa; odds ratio [OR] = 3.07 per 1 mg/dL; P = .02) and eating a PRD (10%-50%: OR = 8.35; P = .01; ≥50%: OR = 5.47; P = .01) were independent nephrocalcinosis risk factors. Cats with absent-to-minimal nephrocalcinosis had increasing plasma creatinine (0.250 ± 0.074 mg/dL/month; P = .002), urea (5.06 ± 1.82 mg/dL/month; P = .01), and phosphate (0.233 ± 0.115 mg/dL/month; P = .05) concentrations over a 1-year period, and had shorter median survival times than cats with mild-to-severe nephrocalcinosis.

Conclusion and Clinical Importance
Higher plasma tCa at CKD diagnosis and PRD intake are independently associated with nephrocalcinosis. However, nephrocalcinosis is not associated with rapid CKD progression in cats.

Citation

Tang, P., Jepson, R., Chang, Y., Geddes, R., Hopkinson, M., & Elliott, J. (2022). Risk factors and implications associated with renal mineralization in chronic kidney disease in cats. Journal of Veterinary Internal Medicine, https://doi.org/10.1111/jvim.16363

• Journal Article Type: Article
• Acceptance Date: Jan 18, 2022
• Publication Date: Jan 19, 2022
• Deposit Date: Feb 10, 2022
• Publicly Available Date: Feb 10, 2022
• Print ISSN: 0891-6640
• Electronic ISSN: 1939-1676
• Publisher: Wiley Open Access
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1111/jvim.16363
• Keywords: calcification; CKD-MBD; hypercalcemia; nephrocalcinosis; GROWTH-FACTOR 23; VITAMIN-D; PHOSPHATE INTAKE; CALCIUM-OXALATE; SURVIVAL; NEPHROCALCINOSIS; PHOSPHORUS; FAILURE; HYPERPARATHYROIDISM; PATHOPHYSIOLOGY
• Public URL: https://rvc-repository.worktribe.com/output/1557235