Appendicitis Hospitalization Care Costs Among Patients With Delayed Diagnosis of Appendicitis.

Importance: Delayed appendicitis diagnosis is associated with worse outcomes. Appendicitis hospital care costs associated with delayed diagnosis are unknown. Objective: To determine whether delayed appendicitis diagnosis was associated with increased appendicitis hospital care costs. Design, Setting, and Participants: This cohort study used data from patients receiving an appendectomy aged 18 to 64 years in 5 states (Florida, Maryland, Massachusetts, New York, Wisconsin) that were captured in the Healthcare Cost and Utilization Project State Inpatient and Emergency Department databases for the years 2016 and 2017 with no additional follow-up. Data were analyzed January through April 2023. Exposures: Delayed diagnosis was defined as a previous emergency department or inpatient hospital encounter with an abdominal diagnosis other than appendicitis, and no intervention 7 days prior to appendectomy encounter. Main Outcomes and Measures: The main outcome was appendicitis hospital care costs. This was calculated from aggregated charges of encounters 7 days prior to appendectomy, the appendectomy encounter, and 30 days postoperatively. Cost-to-charge ratios were applied to charges to obtain costs, which were then adjusted for wage index, inflation to 2022 US dollar, and with extreme outliers winsorized. A multivariable Poisson regression estimated appendicitis hospital care costs associated with a delayed diagnosis while controlling for age, sex, race and ethnicity, insurance status, care discontinuity, income quartile, hospital size, teaching status, medical school affiliation, percentage of Black and Hispanic patient discharges, core-based statistical area, and state. Results: There were 76 183 patients (38 939 female [51.1%]; 2192 Asian or Pacific Islander [2.9%], 14 132 Hispanic [18.5%], 8195 non-Hispanic Black [10.8%], 46 949 non-Hispanic White [61.6%]) underwent appendectomy, and 2045 (2.7%) had a delayed diagnosis. Delayed diagnosis patients had median (IQR) unadjusted cost of $11 099 ($6752-$17 740) compared with $9177 ($5575-$14 481) for nondelayed (P < .001). Patients with delayed diagnosis had 1.23 times (95% CI, 1.16-1.28 times) adjusted increased appendicitis hospital care costs. The mean marginal cost of delayed diagnosis was $2712 (95% CI, $2083-$3342). Even controlling for delayed diagnosis, non-Hispanic Black patients had 1.22 times (95% CI, 1.17-1.28 times) the adjusted increased appendicitis hospital care costs compared with non-Hispanic White patients. Conclusions and Relevance: In this cohort study, delayed diagnosis of appendicitis was associated with increased hospital care costs.