Bidirectional association between pneumonia and intestinal infection: an analysis of the MIMIC-IV database

The purpose is to analyze the prevalence of intestinal infection in patients with pneumonia in intensive care units (ICU) and the impact of intestinal infection on the prognosis of patients with pneumonia, so as to explore the bidirectional association between pneumonia and intestinal infection. The study aims to investigate the correlation between the occurrence of pneumonia and intestinal infection among patients in the ICU, utilizing the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, as well as the impact of intestinal infection on the prognosis of pneumonia patients. The enrolled patients were first divided into pneumonia group and non-pneumonia group, and the primary outcome was that patients developed intestinal infection. Multivariate logistic regression was used to elucidate the association between pneumonia and the prevalence of intestinal infection, and propensity score matching (PSM) and inverse probability of treatment weighing (IPTW) were used to validate our findings. We then divided patients with pneumonia into two groups according to whether they were complicated by intestinal infection, and analyzed the effect of intestinal infection on 28-day mortality, length of ICU stay, and length of hospital stay in patients with pneumonia. This study included 50,920 patients, of which 7493 were diagnosed with pneumonia. Compared with non-pneumonia patients, the incidence of intestinal infection in pneumonia patients was significantly increased [OR 1.58 (95% CI 1.34-1.85; P < 0.001)]. Cox proportional hazards regression model showed no significant effect of co-infection on 28-day mortality in patients with pneumonia (P = 0.223). Patients in the intestinal infection group exhibited a longer length stay in ICU and hospital than those without intestinal infection (P < 0.001). In the ICU, patients with pneumonia were more likely linked to intestinal infection. In addition, the presence of concurrent intestinal infections can prolong both ICU and hospital stays for pneumonia patients.