A nationwide study of the incidence and 30-day mortality rate of pyogenic liver abscess in Denmark, 1977-2002

Background: Pyogenic liver abscess is a life-threatening disease. Accurate data on incidence and prognosis are important, but scarce. Aim: To examine changes in the incidence and 30-day mortality rate of patients with pyogenic liver abscess in Denmark. Methods: Using nationwide administrative registers, we identified all patients diagnosed with pyogenic liver abscess in Denmark, 1977-2002, and their dates of death. We computed annual standardized incidence and 30-day mortality rates, and used Poisson regression to adjust gender-specific mortality rates for year-by-year differences in age at diagnosis. Results: We identified 1448 patients with pyogenic liver abscess, of whom 54% were men. The crude incidence rate for the entire study period was 11.8 per 1 000 000 for men and 9.7 per 1 000 000 for women. Between 1977 and 2002, the incidence rate increased from 6 to 18 per 1 000 000 for men and from 8 to 12 per 1 000 000 for women. The cumulative 30-day mortality rate was 15% for men and 23% for women. The adjusted 30-day mortality rate decreased from 40% for men and 50% for women to around 10% for both genders. Conclusions: In this large nationwide study spanning a 26-year period, we found an increasing incidence rate and a decreasing mortality rate of pyogenic liver abscess. We believe that these changes are primarily explained by more sensitive diagnostic tools.