Factors predicting mortality of patients with lung abscess.

BACKGROUND: The rates of morbidity and mortality associated with lung abscess are still significant despite the introduction of antibiotic treatments. The aim of this work was to identify the factors that predict a poor outcome for patients with lung abscess.

METHODS: We retrospectively reviewed the records and the roentgenographic files of adult patients with lung abscess who were hospitalized from 1980 to 1996 at the Hadassah University Hospital, in Jerusalem, Israel.

RESULTS: The study population comprised 75 patients, and the mean age was 52 years old (range, 12 to 89 years). The mean (+/- SD) hospitalization duration was 25.7+/-21.5 days (range, 5 to 94 days). Fifteen patients (20%) succumbed to the infection. The patients who died had more predisposing factors (+/-SD), such as pneumonia, neoplasm, and altered consciousness, than those who survived, respectively: 2.73+/-1.4 vs 1.9+/-1.3 (p < 0.03). The patients with anemia on admission (hemoglobin levels of < 10 g/dL) had a higher mortality rate than those with higher hemoglobin levels, respectively: 58.3 vs 12.9% (p = 0.0008). A higher mortality rate was also associated with infection by Pseudomonas aeruginosa (83%), Staphylococcus aureus (50%), and Klebsiella pneumoniae (44%). The patients who died had larger abscess volumes (+/-SD) than those who survived (233+/-99 vs 157+/-33 mL), although it did not reach statistical significance. The diameter of the abscess correlated with the hospitalization time (r = 0.5; p < 0.001).

CONCLUSION: High rates of morbidity and mortality are associated with lung abscess despite appropriate antibiotic therapy and better supportive care. In patients with several predisposing factors, such as a large abscess size and a right-lower-lobe location, the prognosis was worse. The patients infected with S aureus, K pneumoniae, and particularly P aeruginosa had an ominous prognosis. As the prognosis for lung abscess has not improved sufficiently since the introduction of antibiotics, other modalities should be considered for patients with poor prognostic signs.