The appendix may protect against Clostridium difficile recurrence.Im GY, Modayil RJ, Lin CT, Geier SJ, Katz DS, Feuerman M, Grendell JH. Clin Gastroenterol Hepatol. 2011 Dec;9(12):1072-7. BACKGROUND; AIMS: Several risk factors have been identified for the development of recurrent Clostridium difficile infection (CDI) that alter host immunity and disrupt colonic flora. Although the function of the appendix has been debated, its active, gut-associated lymphoid tissue and biofilm production indicate potential roles in recovery from initial CDI and protection against recurrent CDI. We investigated whether the presence or absence of an appendix is associated with CDI recurrence.METHODS: We reviewed the medical records of adult inpatients with CDI who were admitted to a tertiary-care teaching hospital from 2005 to 2007 to identify those with and without an appendix. The primary dependent variable for statistical analysis was CDI recurrence.RESULTS: In a multivariate analysis of 11 clinical variables, the presence of an appendix was associated inversely with CDI recurrence (P < .0001; adjusted relative risk, .398). Age older than 60 years also was associated with CDI recurrence (P = .0280; adjusted relative risk, 2.44).CONCLUSIONS: The presence of an appendix has a significant and independent, inverse association with CDI recurrence, but this finding requires validation in a prospective study. Assessing the presence or absence of an appendix might be useful in predicting CDI recurrence.