Hypophosphatemia in cats after renal transplantation.

OBJECTIVE:To report the prevalence of hypophosphatemia after renal transplantation in a historical cohort of cats. DESIGN:Case series. ANIMALS:Cats (n=86) that received a renal allograft. METHODS:Medical records (January 200-June 2006) were reviewed. Signalment, clinical signs, pre- and postoperative diet, pre- and postoperative clinicopathologic variables, renal histopathology, and outcome were retrieved. Prevalence, onset, duration, treatment and associated clinical signs of hypophosphatemia were recorded. A chi(2) test was used to compare hemolysis frequency between cats with normal serum phosphorus concentration or a single spurious low serum phosphorus concentration for <24 hours duration (group 1) and confirmed hypophosphatemia for >24 hours (group 2). A Cox proportional hazards model was used to evaluate the effects of hypophosphatemia on survival while controlling for other potentially confounding variables (age, sex, weight, body condition score, and pre- and 24 hours postoperative clinicopathologic variables). RESULTS:Eighty-six cats (mean age, 7.7 years) were identified. Hypophosphatemia occurred in 32 cats (37%), with a median onset of 2 days and median duration of 4 days. Treatment was initiated in 48 (56%) of hypophosphatemic cats. Survival and hemolysis frequency was not significantly different between groups, and no risk factors were identified. CONCLUSION:Hypophosphatemia occurs in cats after renal transplantation and does not affect survival. CLINICAL RELEVANCE:The clinical importance of hypophosphatemia in renal transplant recipients remains unknown.