Short and long term mortality associated with foodborne bacterial gastrointestinal infections: registry based study * Commentary: matched cohorts can be useful

Abstract

Objectives: To determine the excess mortality associated with infections with Salmonella, Campylobacter, Yersinia enterocolitica, and Shigella and to examine the effect of pre-existing illness. Design: Registry based, matched cohort study. Setting: Denmark. Participants: 48 857 people with gastrointestinal infections plus 487 138 controls from the general population. Main outcome measure: One year mortality among patients with gastrointestinal infections compared with controls after adjustment for comorbidity. Results: 1071 (2.2%) people with gastrointestinal infections died within one year after infection compared with 3636 (0.7%) controls. The relative mortality within one year was 3.1 times higher in patients than in controls. The relative mortality within 30 days of infection was high in all four bacterial groups. Furthermore, there was excess mortality one to six months after infection with Yersinia enterocolitica (relative risk 2.53, 95% confidence interval 1.38 to 4.62) and from six months to one year after infection with Campylobacter (1.35, 1.02 to 1.80) and Salmonella (1.53, 1.31 to 1.79). Conclusions: Infections with all these bacteria were associated with an increased short term risk of death, even after pre-existing illnesses were taken into account. Salmonella, Campylobacter, and Yersinia enterocolitica infections were also associated with increased long term mortality.