Pyogenic liver abscess in the North Denmark Region - a population-based cohort study (2010-2022)

To examine the incidence, clinical characteristics, and outcomes of pyogenic liver abscess (PLA) in a population-based cohort.

We conducted a population-based cohort study of patients diagnosed with PLA in the North Denmark Region from 2010 to 2022. Cases were identified using ICD-10 discharge code (K75.0) and/or microbiology samples, followed by medical record review. We estimated incidence rates, 30-day mortality, and used Cox regression to estimate hazard ratios (HRs) for all-cause mortality within 365 days, stratified by clinical and microbiological factors.

We identified 249 patients (56% male) with a median age of 68 years (IQR, 59-77). The mean annual incidence was 3.1 per 100,000 person-years, increasing from 2.9 in 2010 to 4.8 in 2022. The most common symptoms were fever (57%) and abdominal pain (48%). Biliary tract disease was the most frequent source, accounting for 35%, while 31% were cryptogenic. A microbiological diagnosis was established in 171 patients (69%), most often isolating Escherichia coli and Streptococcus anginosus group. Drainage was performed in 73% of cases, and piperacillin/tazobactam was the most used intravenous antibiotic. The 30-day mortality was 5%, rising to 22% at one year. In multivariable analysis, malignancy (HR 3.19, 95% CI: 1.30-7.82) and polymicrobial abscess cultures (HR 4.15, 95% CI: 1.23-14.07) were associated with increased 365-day all-cause mortality. In contrast, drainage, infected cysts, multifocal abscesses, and blood culture positivity were not.

PLA incidence increased over the study period. While short-term mortality was low, one-year mortality was high among patients with malignancy or polymicrobial infection.