Risk factors for developing metastatic infection from pyogenic liver abscesses

Objectives: The aim of this study was to identify the risk factors for developing extra-hepatic metastases from pyogenic liver abscesses. Methods: We conducted a retrospective study and reviewed 225 patients (age, 19-93 years) with a discharge diagnosis of pyogenic liver abscess from a large medical centre in Taiwan, between January 1995 and June 2000. Clinical data were collected from medical records. Of the 225 patients with a pyogenic liver abscess, 24 had extra-hepatic metastases and were classified into the metastatic infection group; the remaining 201 were classified into the non-metastatic infection group and served as the control group. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by exact logistic regression. Results: After adjustment for age, sex, and the duration of symptoms before admission, diabetes mellitus (adjusted OR, 12; 95% CI, 3.3-67), alcoholism (adjusted OR, 5.2; 95% CI, 1.4-20), the time interval >7 days from the onset of symptoms to the time appropriate antibiotics were administered (adjusted OR, 3.9; 95% CI, 1.2-13), bacteraemia (adjusted OR, 5.4; 95% CI, 1.4-30), and Klebsiella pneumoniae infection (adjusted OR, 5.0; 95% CI, 1.1-47) were associated with the development of extra-hepatic metastases from pyogenic liver abscesses. On the other hand, fever (adjusted OR, 0.28; 95% CI, 0.089-0.92) and right upper quadrant pain/tenderness (adjusted OR, 0.091; 95% CI, 0.0020-0.50) were associated with the non-metastatic abscesses. We performed a multivariate analysis and found that diabetes mellitus (multivariate OR, 7.7; 95% CI, 2.1-29) and alcoholism (multivariate OR, 8.9; 95% CI, 2.6-30) were the independent risk factors for developing metastatic infections; yet right upper quadrant pain/tenderness (multivariate OR, 0.11; 95% CI, 0.014-0.87) was the predictor of no metastatic abscesses. Conclusions: Our data suggest that diabetes mellitus and alcoholism are significant risk factors for developing metastatic infections from pyogenic liver abscesses. These findings seem to imply that underlying conditions of the host influence the development of extra-hepatic metastases from pyogenic liver abscesses.