209 Improving the Diagnostic Stewardship of Clostridioides difficile Infection in a Health System

Abstract

INTRODUCTION: Clostridioides difficile infection (CDI) has been a significant burden for the US health care system in the US with an increasing number of cases diagnosed with CDI annually. Infectious Diseases Society of America (IDSA) and American College of Gastroenterology (ACG) have made recommendations for improved testing of C. difficiletoxin (CDT). This study aims to evaluate a quality improvement initiative to limit inappropriate CDT testing based on established testing criteria. METHODS: In December 2017 a new policy was implemented for CDT testing by polymerase chain reaction (PCR) in the eight acute care hospitals in the midwestern United States. The microbiology lab was granted authority to reject specimens for testing of CDT if the stool sample was formed, the patient had less than three loose bowel movements within 24 hours, used laxatives in the last 48 hours, was tested positive for CDT in the past 14 days or negative in the past 7 days. We performed a 12-month period pre and post-implementation assessment for patients with completed orders for CDT detection by PCR and the number of patients who were diagnosed with CDI over the defined periods. We looked at total tests performed as well as patients who had initial test orders canceled by the lab and then a second order which met the criteria for testing in the same hospital admission. These subgroups were classified to a positive or negative testing result for the CDT test. Patients characteristics, indicators of CDI severity, and clinical comorbidities were correlated between both groups. RESULTS: The number of completed orders for CDT detection with PCR and the number of cases diagnosed with CDI over the 12 months after policy application decreased by 36% and 35% respectively (Figures 1 and 2). 360 patients had CDT testing rejected by the lab post-implementation. Only 80 patients had CDT testing reordered and 16 patients of these tests were positive. In a comparison of the reordered testing, the only independent predictors of a positive test were age above 63-year-old (P 0.013) and serum creatinine (SCr) above 1.5 gm/dl (P 0.025) (Table 1). CONCLUSION: Stricter criteria for CDT testing decreased the number completed CDT ordered tests by 36% and overall CDI cases by 35%. Age greater than 63 and SCr above 1.5 gm/dl may be considered as indications for CDT testing even without fulfilling the criteria for testing. Further prospective studies are needed to identify other risk factors that should be considered independently for CDT testing.