Timing of Biliary Drainage and Clinical Outcomes in Acute Cholangitis: A Single-Center Retrospective Cohort Study

Background and aims: Although guidelines recommend early biliary drainage for acute cholangitis, evidence for optimal timing across severity grades remains limited. We examined associations between drainage timing and both functional and survival outcomes stratified by disease severity using the Tokyo Guidelines 2018 criteria. Methods: This retrospective observational cohort study included 214 consecutive patients with acute cholangitis who underwent endoscopic retrograde cholangiopancreatography between April 2022 and March 2024 at a tertiary center in Okinawa, Japan. Patients were classified according to the 2018 Tokyo Guidelines severity criteria. The primary outcome was discharge disposition (favorable: discharge to pre-admission residence; unfavorable: alternative facility or death). Time from presentation to drainage was analyzed at 12-, 24-, 36-, and 48-hour cutoffs using Fisher's exact test. Results: The cohort comprised 92 Grade I (43%), 83 Grade II (39%), and 39 Grade III (18%) patients. Discharge-to-pre-admission-residence rates were 95% (87/92), 80% (66/83), and 69% (27/39), respectively. For Grade I, drainage within 24 hours was associated with 100% (59/59) discharge to pre-admission residence versus 88% (28/32) beyond 24 hours (P = 0.013). Grade II showed no functional benefit but was associated with improved survival when drainage occurred within 48 hours (99% vs 82%, P = 0.045). Grade III survivors showed better functional recovery with drainage within 24 hours (92% vs 50%, P = 0.014), though this comparison included only 10 patients in the delayed group and should be interpreted with considerable caution. Conclusions: Associations between drainage timing and outcomes varied by severity grade and outcome type. Given the observational design and limited adjustment for confounders, these findings suggest severity-stratified drainage protocols may be beneficial but require validation through prospective studies with multivariable adjustment to establish causality.