Clinical characteristics, prescribing patterns and outcomes in individuals with heart failure and type 1 diabetes versus type 2 diabetes

Background Diabetes mellitus is a common comorbidity in people with heart failure and is associated with worse clinical outcomes. Type 1 and type 2 diabetes are likely to have different disease patterns and pathophysiology in developing heart failure, however research in this area is lacking. The majority of research has focused on type 2 diabetes (T2D). In contrast, there are little data on heart failure in type 1 diabetes (T1D). Aim This study aimed to compare baseline characteristics, use of heart failure guideline-directed medical therapy (GDMT) and all-cause mortality in individuals with incident heart failure and type 1 diabetes and those with heart failure and type 2 diabetes. Methods We conducted an observational study using TriNetX, a global federated health researchnetwork (n=138 million) providing access to real time electronic health records from 142 health care organisations worldwide. We included individuals aged ≥18 years with incident heart failure and type 1 diabetes (n= 7,744) and heart failure and type 2 diabetes (n= 1,049,321) between Feb 2005 and Feb 2025. Propensity score matching for age, gender, and other relevant baseline clinical characteristics was performed. In the matched cohort we assessed prescribing of GDMT and mortality up to 1 year after heart failure diagnosis. Results 45% of the overall cohort was female. Individuals with type 1 diabetes were younger than those with type 2 diabetes at the time of heart failure diagnosis (63.7 ± 15.4 years vs. 69.7 ± 12.4 years, p <0.001) and had fewer comorbidities. Glycaemic control was similar in both groups (HbA1C 7.2 ± 2.1% vs 7.1 ± 1.9%, p=0.41). In the propensity-matched cohort (n=7,367 in both groups), the likelihood of being prescribed GDMT at 1 year following heart failure diagnosis was significantly less in T1D patients compared to T2D. ACE inhibitors/ ARB 71.4% vs. 78.23% p< 0.001, MRA 19.3% vs. 22.1% p<0.001, beta blocker 79.1% vs. 86% p<0.001, SGLT2i 3.3% vs. 7.5% p<0.001. At 1 year heart failure patients with T1D had significantly higher all-cause mortality than those with T2D (unmatched cohort: 17.4% vs. 14.6%, HR 1.19, 95% CI 1.12-1.26, p<0.001; matched cohort: 18.1% vs 12.6%, HR 1.469, 95% CI 1.340, 1.611, p<0.001). Conclusion Despite being younger with fewer comorbidities, individuals with type 1 diabetes and heart failure appeared to have more severe heart failure at baseline than those with type 2 diabetes, with higher NTproBNP at baseline. Individuals with T1D were less likely to be prescribed GDMT and had higher all-cause mortality at 1 year. These results highlight a need for improvements in our understanding of the pathophysiology and treatment options in individuals with T1D and HF.