Antibiotic usage and increasingly aging populations have led to increased incidence of Clostridium difficile infection (CDI) in worldwide. Recent studies in Korea have also reported increasing CDI incidence; however, there have been no reports on the long-term outcomes of CDI. We therefore investigated the long-term clinical outcomes of patients with CDI, including delayed recurrence, associated risk factors and mortality.

Hospitalized patients diagnosed with CDI at Seoul Paik Hospital between January 2007 and December 2008 were included. Their medical records were retrospectively investigated. 'Delayed recurrence' was defined as a relapse 8 weeks after a successful initial treatment. Multivariate logistic regression analysis was performed to identify risk factors for the delayed recurrence. Kaplan-Meier curves were used to analyze mortality rates.

A total of 120 patients were enrolled; among them, 87 were followed-up for at least 1 year, with a mean follow-up period of 34.1±25.1 months. Delayed recurrence was observed in 17 patients (19.5%), and significant risk factors were age (over 70 years, P =0.049), nasogastric tube insertion ( P =0.008), and proton pump inhibitor or H₂-blocker treatments ( P =0.028). The 12- and 24-month mortality rates were 24.6% and 32.5%, respectively. No deaths were directly attributed to CDI.

Delayed recurrence of CDI was not rare, occurring in 19.5% of the study population. Although CDI-related mortality was not reported, 2-year (32.5%) mortality rate of CDI patients implies that a CDI diagnosis may predict severe morbidity and poor prognosis of the underlying disease.