Epidemiologic Factors, Clinical Presentation, Causes, and Outcomes of Liver Abscess: A 35-Year Olmsted County Study

OBJECTIVE: To report the changing incidence, clinical presentation, microbiologic spectrum, and outcomes of pyogenic liver abscess (PLA) in Olmsted County, Minnesota, over the past 35 years. PATIENTS AND METHODS: The Rochester Epidemiology Project was used to identify residents with PLA from January 1, 1980, through December 31, 2014. The study included all patients older than 18 years, with the diagnosis of PLA confirmed through radiographic review and microbiologic cultures. RESULTS: In total, 72 patients received a diagnosis of PLA from 1980 through 2014. The age-adjusted incidence for men was 3.92 cases per 100,000 person-years (95% CI, 2.76-5.09 cases per 100,000 person-years) compared with 1.87 cases per 100,000 person-years (95% CI, 1.15-2.59 cases per 100,000 person-years) for women. Incidence was higher in the period from January 1, 2001, through December 31, 2014, than in the period from January 1, 1980, through December 31, 2000, for women (incidence rate ratio [IRR], 3.8; 95% CI, 1.43-10.09; P=.007) but not for men (IRR, 0.99; 95% CI, 0.55-1.76; P=.96). Fifteen additional patients had postintervention PLA (1980-2000: n=3 of 29 [10.3%] vs 2001-2015: n=12 of 58 [20.6%]). A significant association was seen between age- and sex-adjusted incidence rates of PLA and year of diagnosis (per year since 1980: IRR, 1.04; 95% CI, 1.02-1.07; P<.001) after including postintervention PLA. Streptococcus milleri was the most common organism identified (52.5%). Organisms with multidrug resistance were more common in the period from 2001 through 2014 than in the period from 1980 through 2000 (51% vs 14%; P=.005). The overall mortality rate of PLA was 16.8% (95% CI, 7.6%-25.0%) at 6 months. CONCLUSION: The incidence of PLA is increasing, probably because of increase in frequency of hepatobiliary interventions and organisms with multidrug resistance.