Results
CDIs
The results show a significant reduction in the number of health care facility–associated C. difficile cases during the study period. Initially, we examined the occurrence of C. difficile cases from the period prior to our initiatives (July 2008) through the end of 2013. Looking at the number of cases per quarter and breaking up the analysis into 2 time periods, the earlier period being the data up
to the 4th quarter of 2010, and the later time period being the data from 2011 on, we have the interrupted time series displayed in Figure 2 and Figure 3. Linear regression was performed on each of the segments (Figure 3). The regression for the first segment (earlier time period) was significant (intercept 15.87, 95% confidence interval [CI] 9.31 to 22.42, t = 5.58, P = 0.001; slope –1.19, 95% CI –2.25 to –0.14. t = –2.61, P = 0.031) for the reduction in the number of C. difficile cases, while the regression for the second segment (later time period) was not (intercept 4.35, 95% CI 0.29 to 8.41, t = 2.39, P = 0.038; slope –0.16, 95% CI –0.40 to 0.08, t = –1.46, P = 0.176). Examination of the number of cases per quarter between the 2 time periods (July 2008–December 2010 and January 2011–December 2013) revealed that they differed significantly (Wilcoxon rank sum test, z = 3.91, P < 0.001) (Figure 3).
Within the population of patients having a CDI or recurrence, we found that those patients in the later time period (2011–2013) were significantly less likely to have a recurrence than those in the earlier time period (pre- Jan 2011) (chi square = 5.975, df = 1, P = 0.015). The odds ratio (OR) was 0.35 (95% CI 0.15 to 0.83).
Patients in the earlier (2009–2010) vs. the later post-intervention group (2011–2013) had more likely received multiple antibiotic courses (chi square = 5.32, df = 1, P = 0.021, OR 2.56), a PPI (chi square = 8.86, df = 1, P = 0.003, OR 3.38), and had a health care facility–associated infection originating from our institution as opposed to outside facility transfers or community-acquired cases (chi square = 7.09, df = 1, P = 0.008, OR 2.94).
