The Importance of Considering Different Healthcare Settings When Estimating the Incidence of Clostridium difficile
Methods: We identified CDIs among Kaiser Permanente Northwest (KPNW) patients between June 1, 2005 and December 30, 2012. CDIs were categorized by whether they were diagnosed during an inpatient or outpatient encounter and also by whether they were diagnosed during a face-to-face (e.g., hospitalization, outpatient visit) or non-face-to-face encounter (e.g., phone, email). Our baseline surveillance estimate included only CDIs identified during hospitalization, to represent CDI burden captured through traditional surveillance approaches. We then constructed two additional estimates: one that includes CDIs identified during outpatient face-to-face encounters and one that further includes CDIs identified during non-face-to-face encounters.
Results: During the study time period, we identified 8,024 CDIs. Twenty-four percent of all CDIs (1,944 of 8,024) occurred during a hospitalization, while 6,080 CDIs (76%) were recognized in the outpatient setting. Seventy-nine percent (6,322 of 8,024 CDIs) were identified during face-to-face healthcare encounters; an additional 1,702 CDIs (21% of the total) were identified during a non-face-to-face encounter. Surveillance focused on hospitalized patients would capture less than 25% of the CDI burden among KPNW patients. The addition of cases from outpatient care settings, when added to hospitalizations, would account for 80% of all CDIs. An additional 1,702 CDIs would not be accounted for without the inclusion of non-face-to-face encounters; thus, surveillance approaches that do not include telephone or email encounters would miss 21% of CDIs.
Conclusion: Surveillance approaches that do not include outpatient or non-traditional encounters miss a substantial proportion of CDIs. Failure to capture these cases not only leads to underestimation of disease burden, but also makes it difficult to measure the impact of interventions to control CDI.
See more of: Poster Abstract Session