Understanding the Geographic Distribution of Diverticulitis Hospitalizations in Washington State.

BACKGROUND: The incidence of diverticulitis in the United States is increasing, and hospitalization remains a surrogate for disease severity. State-level characterization of diverticulitis hospitalization is necessary to better understand the distribution of disease burden and target interventions. METHODS: A retrospective cohort of diverticulitis hospitalizations from 2008 through 2019 was created using Washington State's Comprehensive Hospital Abstract Reporting System. Hospitalizations were stratified by acuity, presence of complicated diverticulitis, and surgical intervention using ICD diagnosis and procedure codes. Patterns of regionalization were characterized by hospital case burden and distance travelled by patients. RESULTS: During the study period, 56,508 diverticulitis hospitalizations occurred across 100 hospitals. Most hospitalizations were emergent (77.2%). Of these, 17.5% were for complicated diverticulitis, and 6.6% required surgery. No single hospital received more than 5% (n = 235) of average annual hospitalizations. Surgeons operated in 26.5% of total hospitalizations (13.9% of emergent hospitalizations, and 69.2% of elective hospitalizations). Operations for complicated disease made up 40% of emergent surgery and 28.7% of elective surgery. Most patients traveled fewer than 20 miles for hospitalization, regardless of acuity (84% for emergent hospitalization and 77.5% for elective hospitalization). DISCUSSION: Hospitalizations for diverticulitis are primarily emergent, nonoperative, and broadly distributed across Washington State. Hospitalization and surgery occur close to patients' homes, regardless of acuity. This decentralization needs to be considered if improvement initiatives and research in diverticulitis are to have meaningful, population-level impact.