Lymphopenia as a novel marker of Clostridium difficile infection recurrence

Background: Treatment of Clostridium difficile infection (CDI) is often limited by recurrence in 25% of cases. The objective of this study was to determine risk factors of CDI recurrence during a provincial endemic. Methods: Data was prospectively collected for 1 year in a Montreal hospital. Inclusion criteria were: age >= 18 years; admission for >= 72 h; CDI diagnosis during current admission; no CDI diagnosis in the previous 3 months. Results: A total of 121 patients were included, of which 42% were female. Mean age was 77 years, with a median Charlson comorbidity index of 5. Forty patients (33%) had recurrent disease within 2 months of initial CDI treatment. There were 20 deaths (17%) within the 2-month follow-up period. Higher risk of CDI recurrence was independently associated with older age (HR = 2.26 for each decade), female gender (HR = 1.56), and lymphopenia at completion of CDI treatment (HR = 2.18), while a positive C. difficile antitoxin serology was protective (HR = 0.17). CDI recurrence was not associated with either lymphopenia at time of diagnosis, underlying comorbidities, severity or treatment of the initial CDI episode, or re-exposure to antibiotics during the follow-up period. Conclusion: Lymphopenia at the end of CDI treatment appears to be a strong marker for CDI recurrence. This available and inexpensive test may identify patients who are at higher risk of CDI recurrence. (C) 2012 The British Infection Association. Published by Elsevier Ltd. All rights reserved.