Effect of aluminum hydroxide on serum phosphate and fibroblast growth factor 23 concentrations in young adult cats with surgically induced chronic kidney disease

OBJECTIVE To describe serum fibroblast growth factor 23 (FGF-23) concentrations in young adult cats with remnant kidney model-induced chronic kidney disease (CKD) and to evaluate the effects of orally administered aluminum hydroxide (ALOH) on serum phosphate and FGF-23 concentrations in these cats. ANIMALS 17 adult, purpose-bred cats with induced CKD and 13 healthy, age-matched cats. METHODS A prospective, randomized study. Cats with induced CKD fed a wet renal diet received treatment with ALOH (90 mg/kg/d, PO) on days 0 to 42 and no treatment on days 43 to 84 (treatment group, n = 9) or no treatment on days 0 to 84 (control group, n = 8). Standard serum and urine biochemical analyses and several parameters reflective of calcium-phosphate balance, including serum parathyroid hormone and FGF-23 concentrations, were evaluated at baseline and various time points, including days 42 and 84. Age-matched, healthy, community-owned cats under-- went similar evaluations at a single time point. Baseline data from CKD cats were compared to those of healthy cats. Longitudinal data from CKD cats were compared over time. RESULTS Serum phosphate, total and ionized calcium, and FGF-23 concentrations were significantly higher in CKD cats at baseline relative to healthy cats (all P <= .009). Serum phosphate concentration did not change significantly over time in either CKD group; however, FGF-23 concentrations significantly increased over time in the control group (P P < .02) but not the treatment group (P = .059).