Prognostic value of plasma cortisol concentration in dogs with congestive heart failure

<b>Background</b> – Effects of endogenous cortisol on prognosis for canine congestive heart failure (CHF) are unknown.<br/><br/><b>Objectives</b> – To determine whether higher plasma cortisol concentration was independently associated with increased risk of cardiac mortality in dogs with CHF. Additional study aims were to evaluate the associations between other clinical, neurohormonal, and echocardiographic indices and cardiac mortality.<br/><br/><b>Animals</b> – Thirty client-owned dogs with CHF secondary to myxomatous mitral valve disease (MMVD).<br/><br/><b>Methods</b> – Prospective observational study. Plasma cortisol, urine cortisol-to-creatinine ratio, renal function test results, electrolytes, biomarkers of the renin-angiotensin-aldosterone system, N-terminal pro-B-type natriuretic peptide, and echocardiography were performed in dogs with MMVD at first onset of CHF. Plasma cortisol was repeated 7-14 days later. Association between plasma cortisol and other covariates with survival was determined using proportional hazards regression model.<br/><br/><b>Results</b> – Plasma cortisol was not associated with cardiac or all-cause mortality. Treatment with angiotensin converting enzyme inhibitors (P = 0.021) was associated with longer survival to cardiac mortality. Treatment with spironolactone (P = 0.038), percent fractional shortening (P = 0.034) and lower serum potassium at diagnosis (P = 0.048) were associated with longer survival to all-cause mortality.<br/><br/><b>Conclusions and clinical importance</b> – Plasma cortisol concentrations did not predict cardiac mortality in this sample of dogs with CHF secondary to MMVD.