A systematic review of comorbidities and outcomes of adult patients with pleural infection

BACKGROUND: Pleural infection remains an important cause of mortality. This study aimed to investigate worldwide patterns of pre-existing comorbidities and clinical outcomes of patients with pleural infection. METHODS: Studies reporting on adults with pleural infection between 2000 and 2017 were identified from a search of Embase and Medline. Papers reporting exclusively on tuberculous, fungal or post pneumonectomy infection were excluded. Two reviewers assessed 20 980 records for eligibility. RESULTS: 211 studies met the inclusion criteria. 134 papers (227 898 patients, mean age 52.8 years) reported comorbidity and/or outcome data. The majority of studies were retrospective observational cohorts (n=104, 78%) and the most common region of reporting was East Asia (n=33, 24%) followed by North America (n=27, 20%).85 papers (50 756 patients) reported comorbidity. The median percentage prevalence of any comorbidity was 72% (IQR 58-83%), with respiratory illness (20%, 16-32%) and cardiac illness (19%, 15-27%) most commonly reported. 125 papers (192 298 patients) reported outcome data. The median length of stay was 19 days (IQR 13-27) and median in-hospital or 30-day mortality was 4% (IQR 1-11%).In regions with high-income economies (n=100, 74%) patients were older (mean 56.5 versus 42.5 years, p<0.0001), but there were no significant differences in prevalence of pre-existing comorbidity nor in length of hospital stay or mortality. CONCLUSION: Patients with pleural infection have high levels of comorbidity and long hospital stays. Most reported data are from high-income economy settings. Data from lower-income regions is needed to better understand regional trends and enable optimal resource provision going forward.