Evaluation of plasma-ionized magnesium concentration in 122 dogs with diabetes mellitus: a retrospective study

The goal of this study was to evaluate plasma-ionized magnesium (iMg2+) concentration in a large group of dogs with naturally occurring diabetes mellitus and to determine whether dogs with diabetes mellitus have hypomagnesemia, as reported in diabetic humans and cats. Plasma iMg2+ concentrations were retrospectively evaluated at the time of initial examination of 122 diabetic dogs at the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania. Diabetic dogs were defined as having uncomplicated diabetes mellitus (DM, 78 dogs) diabetic ketoacidosis (DKA, 32 dogs), or ketotic nonacidotic diabetes mellitus (DK, 12 dogs) on the basis of presence or absence of metabolic acidosis or ketonuria. Twenty-two control dogs were used to determine reference values for plasma iMg2+ concentration in healthy dogs. Plasma iMg2+ concentration also was evaluated in 19 nondiabetic dogs with acute pancreatitis because many of the dogs with DKA had concurrent acute pancreatitis. Plasma iMg2+ concentration was significantly higher in dogs with DKA (median 0.41 mmol/L, reference range 0.14-0.72 mmol/L) than in dogs with DM (0.33 mmol/L, 0.17-0.65 mmol/L; P = .0002) or the control group (0.32 mmol/L, 0.26-0.41 mmol/L; P = .006). There were no significant differences between plasma iMg2+ concentrations in dogs with DM or DK compared with control dogs. We conclude that dogs with naturally occurring diabetes mellitus do not have marked hypomagnesemia on initial examination at a tertiary care center.