Prevalence and Prognosis of Hypochloremia in Dogs and Cats

Objective To determine the prevalence, case‐fatality rate, and primary disease processes associated with corrected hypochloremia (hypo[Cl − ]) in dogs and cats. Design Single‐center retrospective study. Setting Electronic medical records were reviewed to identify dogs and cats with at least one chloride and sodium concentration measured simultaneously during a 60‐month period. Animals A total of 17,120 dogs and 4197 cats presented to a veterinary teaching hospital. Interventions None. Measurements and Main Results Measured hypo[Cl − ] was diagnosed in 23.3% (3981/17,120) dogs and 59.0% (2475/4197) cats. Corrected hypo[Cl − ] was diagnosed in 13.9% (2388/17,120) dogs and 34.9% (1463/4197) cats. The case‐fatality rates were higher in animals with measured and corrected hypo[Cl − ] than those with normal corrected [Cl − ] ( p < 0.0001). The case‐fatality rate was also higher in cats with corrected hypo[Cl − ] than those with measured hypo[Cl − ] ( p = 0.0002), but they were not different in dogs ( p = 0.74). Of the dogs and cats with corrected hypo[Cl − ], a total of 74.5% (1779/2388) dogs and 74.6% (1091/1463) cats were categorized as prehospital corrected hypo[Cl − ], and a total of 20.9% (498/2388) dogs and 17.3% (253/1463) cats were categorized as hospital‐acquired corrected hypo[Cl − ]. The case‐fatality rates of dogs and cats with hospital‐acquired corrected hypo[Cl − ] were higher than those with prehospital corrected hypo[Cl − ] ( p < 0.0001). Various primary disease processes were identified in animals with corrected hypo[Cl − ]. Of these, urologic, cardiovascular, and gastrointestinal diseases were the three most common disease processes identified in dogs and cats with corrected hypo[Cl − ]. Conclusions Corrected hypo[Cl − ] was a common electrolyte abnormality and was associated with higher case‐fatality rates than normal corrected [Cl − ]. Various disease processes were associated with corrected hypo[Cl − ], and closer attention to corrected hypo[Cl − ] is warranted.