The risk of appendiceal rupture based on hospital admission source.

OBJECTIVE: To determine whether admission source is a potential risk factor for appendiceal rupture. METHODS: Administrative data were obtained from the California Office of Statewide Health Planning and Development for all patients in San Diego County with the primary diagnosis of appendicitis during 1993. The appendiceal rupture ratio was defined as those coded as ruptured (ICD-9-CM codes 540.0 and 540.1) divided by both ruptured and non-ruptured cases (540.9). The odds ratio of appendiceal rupture from routine outpatient office or clinic venues vs those admitted through the ED were calculated using multivariate logistic regression analysis to adjust for age, sex, race, comorbidity, insurance status, and home address to hospital proximity. RESULTS: There were a total of 1,906 patients, of whom 663 (34.8%) had appendiceal ruptures. Of the 1,360 (71.4%) admitted from the ED, 422 (31.0%) had ruptures, compared with 211 (43.3%) of the 487 admitted from outpatient sources (p < 0.0001). Patients with appendicitis directly admitted from outpatient sources were more likely to be complicated by appendiceal rupture than were those admitted through the hospital ED (adjusted odds ratio 1.62, 95% CI = 1.28 to 2.05, p < 0.0001). CONCLUSION: Patients with appendicitis admitted from outpatient sources are more likely to have appendiceal rupture than are those admitted from the ED.