Long‐term incidence and risk of noncardiovascular and all‐cause mortality in apparently healthy cats and cats with preclinical hypertrophic cardiomyopathy

Background Epidemiologic knowledge regarding noncardiovascular and all‐cause mortality in apparently healthy cats (AH) and cats with preclinical hypertrophic cardiomyopathy (pHCM) is limited, hindering development of evidence‐based healthcare guidelines. Objectives To characterize/compare incidence rates, risk, and survival associated with noncardiovascular and all‐cause mortality in AH and pHCM cats. Animals A total of 1730 client‐owned cats (722 AH, 1008 pHCM) from 21 countries. Methods Retrospective, multicenter, longitudinal, cohort study. Long‐term health data were extracted by medical record review and owner/referring veterinarian interviews. Results Noncardiovascular death occurred in 534 (30.9%) of 1730 cats observed up to 15.2 years. Proportion of noncardiovascular death did not differ significantly between cats that at study enrollment were AH or had pHCM (P = .48). Cancer, chronic kidney disease, and conditions characterized by chronic weight‐loss‐vomiting‐diarrhea‐anorexia were the most frequently recorded noncardiovascular causes of death. Incidence rates/risk of noncardiac death increased with age in AH and pHCM. All‐cause death proportions were greater in pHCM than AH (65% versus 40%, respectively; P < .001) because of higher cardiovascular mortality in pHCM cats. Comparing AH with pHCM, median survival (study entry to noncardiovascular death) did not differ (AH, 9.8 years; pHCM, 8.6 years; P = .10), but all‐cause survival was significantly shorter in pHCM (P = .0001). Conclusions and Clinical Importance All‐cause mortality was significantly greater in pHCM cats due to disease burden contributed by increased cardiovascular death superimposed upon noncardiovascular death.