Prognostic Implications of Diabetes Insipidus in Heart Failure Hospitalizations: Insights from the U.S. National Readmissions Database 2016–2021

<b>Background:</b> Diabetes insipidus affects heart failure outcomes through its impact on volume status and electrolyte imbalance. However, previous data on its impact on heart failure hospitalizations are limited. This study aimed to evaluate the prognostic implications of diabetes insipidus in patients admitted with heart failure. We utilized the United States National Readmissions Database (NRD) from the years 2016 to 2021. <b>Methods:</b> Adult patients hospitalized with a primary diagnosis of heart failure were stratified based on the presence of diabetes insipidus. Propensity matching was used to balance the baseline characteristics. Multivariable logistic regression was used to estimate the association of heart failure with diabetes insipidus on clinical outcomes, complications, 30-day readmissions, and healthcare utilization. <b>Results:</b> Among 5,946,749 heart failure hospitalizations, 2846 (0.04%) had a secondary diagnosis of diabetes insipidus. Compared with matched control, patients with heart failure and diabetes insipidus had significantly higher in-hospital mortality (odds ratio [OR] 5.77 [95% CI, 4.78-6.97], <i>p</i> < 0.001). Patients with heart failure and diabetes insipidus were also associated with increased odds of acute kidney injury (OR 2.11 [95% CI, 1.86-2.39], <i>p</i> < 0.001), hypernatremia (OR 4.98 [95% CI, 1.86-2.39], <i>p</i> < 0.001), cardiogenic shock (OR 1.69 [95% CI, 1.32-2.15], <i>p</i> < 0.001), and cerebral edema (OR 22.28 [95% CI, 14.74-33.69], <i>p</i> < 0.001) compared with the matched controls. No difference was found in the all-cause readmission (OR 0.89 [95% CI, 0.76-1.04], <i>p</i> = 0.14), but patients with diabetes insipidus had a lower risk of heart failure readmissions (OR 0.47 [95% CI, 0.33-0.66], <i>p</i> < 0.001) and a higher risk of non-cardiac readmissions (OR 2.21 [95% CI, 1.48-3.9], <i>p</i> < 0.001). <b>Conclusions:</b> Diabetes insipidus was associated with worse outcomes in patients with primary heart failure hospitalizations, which was likely secondary to the risk of excessive diuresis.