Burden and Impact of Infections in Acute Pancreatitis: Insights from the National Inpatient Sample

Acute pancreatitis (AP) is an inflammatory disease with a wide range of severity. Disruption of the intestinal barrier and translocation of gut flora increase the risk of infectious complications. Our study evaluates the impact of infections on in-hospital outcomes among admitted AP patients.

Hospitalized adult AP patients were identified from the National Inpatient Sample (NIS) database (2016-2022) using ICD-10 codes. Patients with missing demographic or mortality data were excluded, and those remaining were stratified by infection type. Demographics, AP etiology, comorbidities, and clinical outcomes were analyzed. The primary outcome was in-hospital mortality by infection type. Secondary outcomes included sepsis, shock, acute kidney injury (AKI), intensive care unit (ICU) admission, deep vein thrombosis (DVT), pulmonary embolism (PE), and portal vein thrombosis (PVT).

Among 2,467,233 patients with AP, 392,255 (15.9%) developed infectious complications. Urinary tract infections (UTIs) were most common (51%), followed by pneumonia (29.7%), cholangitis (14.5%), Clostridioides difficile infection (CDI) (7.9%), cellulitis (5.6%), and spontaneous bacterial peritonitis (SBP) (1.9%). SBP had the highest mortality (21.1%), followed by pneumonia (12.8%), whereas mortality was lower with UTI (4.5%), cholangitis (5.2%), CDI (6.9%), and cellulitis (5.9%). AP patients with infections had higher in-hospital mortality after adjusting for confounding factors (6.7% vs 1.6%, p < 0.001).

Infectious complications, particularly SBP and pneumonia, were associated with significantly worse in-hospital outcomes in patients with AP, highlighting the importance of early recognition and management.