Outpatient antibiotic use and the incidence of acute appendicitis in Finland: a nationwide study from 1990-2008.

BACKGROUND

The incidence of acute appendicitis (AA) has decreased in Finland. We hypothesized that changing trends in outpatient antibiotic use might explain at least part of this declining incidence of AA.

METHODS

The number of all patients with AA in Finland was extracted from the national data base from 1990 to 2008. For comparison, the incidence of acute diverticulitis of the colon (AD) was also recorded. All outpatient prescriptions of antibiotics belonging to the major groups of these drugs were also recorded. We used unit root and co-integration analyses for statistical analysis of the data in the study.

RESULTS

The incidence of AA in Finland declined from 14.5 to 9.8 per 10,000 inhabitants (32%) and the incidence of AD increased by 47% between 1993 and 2007. The total outpatient use of antibiotics did not increase during this same period, but the use of antibiotics effective widely against colonic pathogens (macrolides, fluoroquinolones, and cephalosporins) increased significantly. No correlation was found between the incidence of AA, that of AD, and the use of different groups of antibiotics.

CONCLUSIONS

Our nationwide registry study indicated that changes in outpatient antibiotic use do not explain the decreasing trend in AA in Finland. Other factors, such as improved diagnosis of AA, may have some role in the decreasing incidence of AA.