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Published on: June 2, 2022
Ionized hypercalcemia in cats with azotemic chronic kidney disease (2012-2018)
Dirk Hendrik Nicolaas van den Broek1, Rebecca F Geddes1, Nicola S Lötter2
1Department of Clinical Science and Services, Royal Veterinary College, University of London, London, United Kingdom.
Insights
Ionized hypercalcemia is common in cats with chronic kidney disease (CKD), affecting 20% at diagnosis. Monitoring ionized calcium is crucial for early detection and management in feline CKD patients.
Area of Science:
- Veterinary Medicine
- Nephrology
- Endocrinology
Background:
- Hypercalcemia is a known complication in feline chronic kidney disease (CKD).
- Previous studies have not focused on the physiologically relevant ionized calcium fraction in cats with CKD.
Purpose of the Study:
- To determine the prevalence and incidence of ionized hypercalcemia in cats with azotemic CKD.
- To identify predictors of ionized hypercalcemia in this feline population.
Main Methods:
- A cohort of 164 client-owned cats with azotemic CKD was studied.
- Binary logistic regression and Cox proportional hazards models were used to analyze predictor variables for ionized hypercalcemia at diagnosis and over time.
Main Results:
- Twenty percent of cats (33/164) had ionized hypercalcemia at diagnosis, associated with male sex, higher total calcium and potassium, and lower parathyroid hormone.
- Of initially normocalcemic cats, 26% developed ionized hypercalcemia within 140 days; only body condition score predicted incident ionized hypercalcemia.
Conclusions:
- Ionized hypercalcemia occurs frequently in cats with azotemic CKD.
- Regular monitoring of blood ionized calcium concentrations is recommended for cats with CKD.
Background:
Hypercalcemia is associated with chronic kidney disease (CKD) in cats, but studies assessing the physiologically relevant ionized calcium fraction are lacking.
Objectives:
To describe the prevalence and incidence rate of ionized hypercalcemia, and to explore predictor variables to identify cats at risk of ionized hypercalcemia in a cohort of cats diagnosed with azotemic CKD.
Animals:
One hundred sixty-four client-owned cats with azotemic CKD.
Methods:
Variables independently associated with ionized hypercalcemia at diagnosis of azotemic CKD were explored by binary logistic regression. Cats that were normocalcemic at diagnosis of azotemic CKD were followed over a 12-month period or until ionized hypercalcemia occurred and baseline predictor variables for ionized hypercalcemia explored using Cox proportional hazards and receiver operating characteristic curve analysis.
Results:
Ionized hypercalcemia (median, 1.41 mmol/L; range, 1.38-1.68) was observed in 33/164 (20%) cats at diagnosis of azotemic CKD and was associated with male sex, higher plasma total calcium and potassium concentrations, and lower plasma parathyroid hormone concentrations. Twenty-five of 96 initially normocalcemic (26%) cats followed for minimum 90 days developed ionized hypercalcemia (median, 1.46 mmol/L; range, 1.38-1.80) at a median of 140 days after diagnosis of azotemic CKD (incidence rate, 0.48 per feline patient-year). Only body condition score was independently associated with incident ionized hypercalcemia.
Conclusions And Clinical Importance:
The occurrence of ionized hypercalcemia is high in cats with CKD. Continued monitoring of blood ionized calcium concentrations is advised.
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