Prognostic factors of lung abscess: a single-center retrospective cohort study

A lung abscess, a localized suppurative necrosis of the lung parenchyma, remains a serious condition despite modern antibiotic therapy, with many patients requiring invasive procedures due to treatment failure. Identifying these high-risk patients is crucial, but robust prognostic factors are not well-established due to methodological limitations in prior studies, such as reliance on univariate analyses or heterogeneous endpoints. We, therefore, conducted a 20-year retrospective study to identify predictors for a composite outcome of treatment failure, defined as in-hospital death, drainage, or surgery. This single-center, retrospective cohort study included patients with lung abscesses who were hospitalized and initially managed with conservative antibiotic therapy at the Department of Pulmonology, Kameda Medical Center, between April 2004 and June 2024. The primary endpoint was treatment failure, defined as a composite of computed tomography-guided percutaneous catheter drainage of the lung abscess, surgery, and in-hospital death. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for treatment failure were calculated using multivariate logistic regression analysis, adjusting for potential predictive variables, such as age, sex, comorbidity, and abscess characteristics, based on previous studies. This study included 109 patients (mean age: 74 years), of whom 21 (19.3%) were female. Treatment failure was observed in 17 (15.6%) patients, including 9 (8.3%) in-hospital deaths, 1 (0.9%) surgical intervention, and 11 (10.1%) cases requiring CT-guided drainage of the lung abscess. Some patients experienced multiple outcomes. The aORs for treatment failure were as follows: age (aOR = 1.01, p = 0.737), female sex (aOR = 0.31, p = 0.297), maximum abscess diameter (aOR = 1.45, p = 0.006), presence of diabetes (aOR = 0.16, p = 0.070), and presence of multilocular abscesses (aOR = 3.88, p = 0.030). Notably, the abscess cavity size and multilocular formation were significantly associated with an increased risk of treatment failure. Abscess size and multiloculation are significant prognostic factors of lung abscess treatment failure. Early detection through imaging and laboratory evaluations may aid in risk stratification and prompt clinical decision-making. The participants were registered retrospectively.