Aspirin use is associated with reduced risk for recurrence of pyogenic liver abscess: a propensity score analysis

Aspirin possesses anti-bacterial activity that may prevent recurrence of Klebsiella pneumoniae pyogenic liver abscess (KP-PLA). In ex-vivo study, aspirin was administered before bactericidal assay against serotype K1 K. pneumoniae. We identified 5,912 patients with PLA who had no known pre-existing hepatobiliary diseases or malignancy in Taiwan from 1999 to 2013 from nationwide cohort study. Multivariate Cox proportional hazards regression models was used to estimate the hazard ratios [HR] for the association between aspirin use and recurrent PLA. The PLA recurrence rate in patients taking aspirin daily for 30 or more days, from 90 days before to 90 days after the first PLA episode (aspirin users), and aspirin non-users was 42.5 and 74.6 per 1,000 person-years of follow-up, respectively. The population-based study showed a HR for PLA recurrence in aspirin users of 0.50 (95% confidence interval, 0.35-0.69), relative to that in non-users, after adjustments for confounders. An ex-vivo study indicated that aspirin was able to significantly enhance bacterial killing by leukocytes, whether collected from diabetic patients with KP-PLA recurrence or from healthy volunteers. Our results suggest that aspirin is associated with reduced risk for PLA recurrence among Taiwanese with PLA who had no preexisting hepatobiliary diseases or malignancy.