BackgroundThis study aimed to characterize the association of preoperative acute cholangitis (PAC) with surgical outcomes and healthcare costs. MethodsPatients who underwent pancreaticoduodenectomy (PD) between 2013 and 2021 were identified using 100% Medicare Standard Analytic Files. PAC was defined as the occurrence of at least 1 episode of acute cholangitis within the year preceding surgery. Multivariable regression analyses were used to compare postoperative outcomes and costs relative to PAC. ResultsAmong 23,455 Medicare beneficiaries who underwent PD, 2,217 patients (9.5%) had at least 1 episode of PAC. Most patients (n = 14,729 [62.8%]) underwent PD for a malignant indication. On multivariable analyses, PAC was associated with elevated odds of surgical site infection (odds ratio [OR], 1.14; 95% CI, 1.01–1.29), sepsis (OR, 1.17; 95% CI, 1.01–1.37), extended length of stay (OR, 1.13; 95% CI, 1.01–1.26), and readmission within 90 days (OR, 1.14; 95% CI, 1.04–1.26). Patients with a history of PAC before PD had a reduced likelihood of achieving a postoperative textbook outcome (OR, 0.83; 95% CI, 0.75–0.92) along with 87.8% and 18.4% higher associated preoperative and postoperative healthcare costs, respectively (all P < .001). Overall costs increased substantially among patients with more than 1 PAC episode ($59,893 [95% CI, $57,827-$61,959] for no episode vs $77,922 [95% CI, $73,854-$81,990] for 1 episode vs $101,205 [95% CI, $94,871-$107,539] for multiple episodes). ConclusionApproximately 1 in 10 patients undergoing PD experienced an antecedent PAC episode, which was associated with adverse surgical outcomes and greater healthcare expenditures.