Population-Based Study of the Epidemiology of and the Risk Factors for Pyogenic Liver Abscess

Background & Aims: Pyogenic liver abscess (PLA) is relatively uncommon in North America but is associated with significant morbidity and mortality. Our objective was to characterize the incidence of, risk factors for, and outcomes of PLA in a nonselected population. Methods: Population-based surveillance was conducted in the Calgary Health Region (CHR) between April 1, 1999 and March 31, 2003. All adult CHR residents with PLA were identified, and charts were reviewed. Results: Seventy-one CHR residents developed a PLA for an annual incidence of 2.3 per 100,000 population. There was an increasing incidence of PLA with advancing age. Men were at much higher risk of acquiring a PLA as compared to women (3.3 vs 1.3 per 100,000; relative risk [RR], 2.6; 95% confidence interval [CI], 1.5-4.6; P < .001), and this was observed across all age groups. A number of comorbid conditions were associated with significantly higher risk for developing a PLA including liver transplantation patients (RR, 444.8; 95% CI, 89.5-1356.0; P < .0001), diabetics (RR, 11.1; 95% CI, 6.3-19; P < .0001), and patients with a history of malignancy (RR, 13.3; 95% CI, 6.9-24.4; P < .0001). No other solid organ transplantation patient was at increased risk. All patients required admission to hospital (median length of stay, 16 days), and 7 (10%) patients died in hospital, corresponding to a mortality rate of 0.22 per 100,000 population. Conclusions: This study provides important data on the burden of PLA and identifies risk groups that might potentially benefit from preventive efforts.