Incidence of acute diverticulitis compared to appendicitis in emergency wards: a 10-year nationwide register and cohort study from Finland.

BACKGROUND: The two most common abdominal infections in emergency departments (ED) are acute appendicitis (AA) and sigmoid diverticulitis (AD). The frequency of ED visits for diverticulitis has increased strongly in many countries during recent decades. The aim of this study was to analyze the nationwide changes in AD rate requiring hospital admission compared to AA during a 10-year study period. METHODS: Register data of AD and AA in the whole of Finland were obtained between the years 2009 and 2018. Changes in the incidence and surgical treatment of AD in the whole country were compared to those of AA. Patient demographics and treatment of AD were analyzed in greater detail from a smaller cohort (n = 614). RESULTS: The incidence of AD increased from 262 to 413 cases (58%) per 100,000 inhabitants during 10 years and emergency surgery for AD decreased from 27 to 24 cases per 100,000 (11%). The incidence of AA remained stable and varied from 118 to 124 annual cases per 100,000 inhabitants. In a patient cohort of AD (n = 614), most of the patients (68%) had only one episode of diverticulitis during 10 years; 16% were operated urgently, with a mortality of 8%. Disease-specific mortality increased from 0% to 5.7% along with patient age when comparing the age groups <50 years and > 70 years, respectively. CONCLUSIONS: Our study indicates that the incidence of acute diverticulitis is still increasing and is now 2-3 times higher than that of appendicitis in emergency departments.