Long-term mortality in patients diagnosed with Listeria monocytogenes meningitis: a Danish nationwide cohort study.

OBJECTIVES: To determine the long-term mortality, the causes of death and the incidence of cancer in listeria meningitis patients. METHODS: Nationwide, population-based cohort study including all adult patients diagnosed with listeria meningitis from 1977 to 2006 and alive 1 year after diagnosis, and an age-and gender-matched, population control cohort. Kaplan-Meier tables, Cox regression analysis and cumulative incidence function were used as outcome analyses. RESULTS: We identified 114 listeria meningitis patients and 1026 population controls. The adjusted mortality rate ratio (MRR) for listeria meningitis patients the first 5 years of follow-up was 2.35(95% confidence interval (CI) 1.60-3.45) thereafter the MRR was 0.93(95% CI: 0.56-1.55). Listeria meningitis patients had an increased risk of death due to cancer the first 5 years of follow-up, and in the same period patients above 50 years of age had a 2-fold increased risk of being diagnosed with cancer, thereafter the risks declined to that of the background population. CONCLUSIONS: The long-term mortality in adult patients diagnosed with listeria meningitis was increased the first 5 years of follow-up, mainly due to death from cancer, thereafter the mortality did not differ from the background population. To improve survival this patient population should be meticulously screened for predisposing conditions, mainly underlying malignant diseases.