MON-644 - Impact of Preexisting Type 1 Diabetes on Hospital Outcomes in Acute-on-Chronic Heart Failure: A Nationwide Analysis (2016-2022).

BACKGROUND
Type 1 diabetes mellitus (T1DM) is associated with an increased risk of heart failure, yet most epidemiologic studies combine T1DM and type 2 diabetes. Data specifically examining the impact of preexisting T1DM on inpatient outcomes among patients hospitalized with acute-on-chronic congestive heart failure (ACCHF) are limited. This study evaluated inpatient outcomes of adults admitted with first-time ACCHF and preexisting T1DM using a nationally representative database.

METHODS
We conducted a retrospective cohort study using the HCUP-NIS database from 2016 to 2022. Adult patients (≥18 years) with a principal diagnosis of acute-on-chronic CHF were identified using the ICD-10-CM codes. Patients were stratified into two groups based on the presence or absence of preexisting Type 1 DM as a secondary diagnosis.
The primary outcome was in-hospital mortality. Secondary outcomes included length of stay (LOS) and total hospitalization costs as well as various inpatient procedures including invasive hemodynamic monitoring, intubation, and noninvasive ventilation.
Multivariable logistic regression and linear regression models were used to adjust for potential confounders including age, sex, race, insurance status, hospital characteristics, and comorbidities (Charlson Comorbidity Index, atrial fibrillation, hypertension, diabetes mellitus, chronic kidney disease, and coronary artery disease).

RESULTS
Among 479,595 hospitalizations for acute on chronic congestive heart failure, 76,705 patients (16%) had preexisting T1DM. After multivariable adjustment, patients with T1DM had a statistically significant increase in length of stay compared with those without T1DM (adjusted mean difference: +0.21 days; p = 0.001). Despite longer hospitalizations, T1DM was associated with a significant reduction in mean total hospitalization charges by $21,130 (p < 0.001).
There was no statistically significant difference in in-hospital mortality between patients with and without T1DM. Additionally, utilization of invasive monitoring, intubation, and noninvasive ventilation did not differ significantly between the two groups.

CONCLUSION
In this nationwide analysis, Type 1 diabetes mellitus was associated with longer hospital stays but lower inpatient costs among adults hospitalized for acute on chronic heart failure, without an observed increase in in-hospital mortality or procedural utilization. These findings suggest that while T1DM confers a distinct inpatient resource utilization profile, it does not independently worsen short-term mortality in ACCHF admissions. Further studies are needed to elucidate the mechanisms underlying these differences and to define endocrine-informed strategies for optimizing inpatient heart failure care in patients with T1DM.

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