Causative pathogens and clinical outcomes of pleural infection in patients without and with indwelling pleural catheters – a retrospective study from a Danish pleural clinic

Background
Indwelling pleural catheters (IPCs) are increasingly used for recurrent pleural effusions, but carries a monthly 3% risk for developing pleural infection (PI) with a mean time from insertion to infection of 2 months, and with Staphylococci as the main pathogen. Little is known of IPC related PI in Danish patients. We aimed at filling the gap by determining monthly infection rate and to compare causative pathogens and clinical outcomes between IPC-related and non-IPC-related PI in our clinic.

Methods
We conducted a single-centre retrospective review of electronic medical files to identify patients with IPC and/or PI treated in our department between 2018 and 2022. Data on basic demography, infection rate, time to IPC-related infection, RAPID score, pathogens, days of antibiotics (oral, intravenous), days in hospital, and mortality were recorded.

Results
In total, the 54 patients had a median exposure to IPC of 290.9 months, and 13 (24%) developed PI with a median time to PI of 5.1 months with a monthly PI risk of 1.045 (95% CI 1.020–1.069). A comparator group of 28 patients were treated for non-IPC related PI. The causative pathogen was identified for 85% in the IPC group (Staphylococci 91%) compared to 50% in non-IPC group (Staphylococci 0%). Duration of intravenous drug therapy (10 vs 15 days) and hospital admission (13 vs 17 days) were significantly shorter (p-value 0.047). A high RAPID score (renal, age, purulence, infection source, and dietary factors) (62% vs 25%) and 30-days mortality (23% vs 4%) were significantly more common in the IPC group. However, PI-related death did not differ (8% vs 7%).

Conclusion
We found that longer IPC exposure was related to increased pleural infection rate, but with the same pattern as earlier reports on shorter IPC exposure, thus a monthly infection rate below 5%, pathogens dominated by Staphylococci, and a low pleural infection-related mortality.