Is Type 2 Diabetes Mellitus an Independent Risk Factor for Mortality in Hypertrophic Cardiomyopathy?

Background: The mortality rate of hypertrophic cardiomyopathy (HCM) has decreased between 1999 and 2020. The risk factors for sudden cardiac death (SCD) in HCM were updated in the American Heart Association (AHA)/American College of Cardiology Foundation (ACCF) 2020 guidelines by adding new risk factors, like the late gadolinium enhancement on cardiac magnetic resonance imaging (MRI). Type 2 diabetes mellitus (T2DM) is a major risk factor for most cardiac diseases; however, it is not included in these guidelines due to a lack of strong evidence of a correlation between T2DM and mortality in HCM. Therefore, we sought to investigate if T2DM increases the 5-year risk rate for adverse outcomes, such as heart failure and all-cause mortality in patients with HCM. Methods: We collected patient data from January 1, 2018, to March 1, 2023, using the TriNetX database. The sample included 80,502 individuals with HCM, then divided into two cohorts based on the absence (58,573; cohort 1) or presence (15,296; cohort 2) of T2DM. The two matched groups then underwent survival and risk analyses for all-cause mortality or the first incidence of heart failure diagnosis within 5 years from the point in time when the selection criteria were first met. Results: We found a statistically significant increase in all-cause mortality and new-onset heart failure in HCM patients with diabetes compared to those without diabetes after adjusting for major risk factors. Conclusions: This is one of the largest retrospective cohort studies that examined the correlation between T2DM and adverse outcomes in patients with HCM. This underlines the need for future prospective studies investigating the effects of T2DM on HCM outcomes.