Association between serum fibroblast growth factor-23 concentrations and blood calcium levels in chronic kidney disease cats with upper urolithiasis

Abstract

Objectives This study investigated whether serum fibroblast growth factor (FGF)-23 concentrations are associated with serum total calcium (tCa) and blood ionised calcium (iCa) concentrations in cats with chronic kidney disease (CKD) and upper urolithiasis. Methods Serum samples and the medical records of cats with CKD with nephroliths, ureteroliths or both were investigated retrospectively. Cats with a serum creatinine concentration >250 μmol/l and/or a serum phosphorus concentration ⩾1.50 mmol/l were excluded. Based on cut-offs for serum tCa (2.70 mmol/l) or blood iCa (1.40 mmol/l), cats were divided into the following groups: total hypercalcaemia (H-tCa) (>2.70 mmol/l) and total normocalcaemia (N-tCa) (⩽2.70 mmol/l) groups, or ionised hypercalcaemia (H-iCa) (>1.40 mmol/l) and ionised normocalcaemia (N-iCa) (⩽1.40 mmol/l) groups, respectively. Serum FGF-23 concentrations were compared between groups and correlation analysis was performed. Results Thirty-two cats with CKD and upper urolithiasis were included. Serum FGF-23 concentrations in the H-tCa group (median 573 pg/ml [range 125–3888]; n = 12) were significantly higher compared with the N-tCa group (median 245 pg/ml [range 94–627]; n = 20) ( P = 0.001). Serum FGF-23 concentrations in the H-iCa group (median 1479 pg/ml [range 509–3888]; n = 6) increased significantly compared with the N-iCa group (median 245 pg/ml [range 94–637]; n = 26) ( P <0.001). Serum FGF-23 concentrations significantly correlated with serum tCa ( r = 0.511, P = 0.003) and blood iCa concentrations ( r = 0.425, P = 0.015) but not serum creatinine ( r = 0.279, P = 0.122) or phosphorus concentrations ( r = 0.208, P = 0.253). Conclusions and relevance Increased serum FGF-23 concentrations were associated with hypercalcaemia independently of creatinine and phosphate status in cats with CKD and upper urolithiasis.

Blood fibroblast growth factor 23 concentration in cats with and without chronic kidney disease: a scoping review

“…It was not possible to determine from the information available in the publications if results from individual cats were used in multiple studies or how often or how many overlapping data points may be in the data sets. The two studies performed in Japan 32 , 33 likely also have overlapping data points, but this is similarly unclear. These studies that may have overlapping patient populations included cats with IRIS stage 1 and 2 CKD.…”

“…Five studies subdivided cats by CKD stage, of which four studies provided descriptive information about FGF-23 concentrations by IRIS stage ( Table 3 ; see Figure 1 in the supplementary material). 19 , 25 , 28 , 32 , 33 All these studies used the creatinine concentration to stage. Four studies 19 , 28 , 32 , 33 used the 2019 IRIS staging guidelines (stage 2: 1.6–2.8 mg/dl; stage 3: 2.9–5.0 mg/dl; stage 4: >5 mg/dl); however, one study 19 used a creatinine concentration in the range of 2.1–2.8 mg/dl to subclassify cats as stage 2 CKD.…”

“…Studies reported that total calcium (Geddes et al 19 ) and ionized calcium (Miyakawa et al 32 ) concentrations were independent predictors of FGF-23 concentrations in cats with CKD. Miyakawa et al 33 found that in cats with CKD and upper urolithiasis, FGF-23 concentrations were higher in those cats with ionized hypercalcemia and a normal phosphorus concentration (<4.6 mg/dl). In that study, FGF-23 the Deyinhengda assay for healthy cats and cats with chronic kidney disease (CKD) stages 1-4.…”

“…FGF-23 concentrations were found to positively correlate with serum phosphorus concentrations in cats with CKD in some studies 20,25,28,32 but some studies showed no correlation. 18,26,33,34 Geddes et al 19 found that phosphorus concentration was an independent predictor of FGF-23 in cats with stage 2-4 CKD. The same study subdivided cats with CKD by stage 2 and 3 and by phosphorus concentration (stage 2: ⩽4.5 mg/dl; stage 3: ⩽5.0 mg/dl) and found that FGF-23 concentrations were significantly higher in cats with phosphorus concentrations above the cutoff (Table 4).…”

Effect of phosphate binder therapy on FGF-23 levels in dialysis patients

“…Хроническая болезнь почек (ХБП) является независимым фактором риска сердечно-сосудистых заболеваний и смертности [1,2]. Нарушения минерального обмена, такие как гиперфосфатемия и дефицит витамина D, часто встречаются у пациентов с ХБП и тесно связаны с повышенным риском летальности [3]. FGF-23 регулирует метаболизм фосфатов и витамина D благодаря своему сильному фосфатурическому действию и ингибированию активности 1α-гидроксилазы витамина D в проксимальных канальцах почек [4].…”