477. Trends in the Incidence of Community-Associated and Healthcare-Associated Clostridium difficile Infections in Quebec Over a 7-Year Period (2008–2015)

Abstract

Background Clostridium difficile infections (CDI) affect hospitalized patients but also individuals in the community. The epidemiology of healthcare-associated (HA) CDI has received much scrutiny, but little is known regarding trends in the incidence rate of community-associated (CA) cases. We describe and compare long-term trends in the provincial incidence rate of CA-CDI and HA-CDI.MethodsHospitalized patients with CA-CDI and HA-CDI were identified prospectively between April 2008 and April 2015 through the Quebec CDI surveillance program (QCISP), a network of 95 acute-care institutions using standardized case definitions. Hospitalized CDI cases are classified as CA if they occur within 3 days of admission or >4 weeks after any inpatient or outpatient care. CDI cases are defined as HA-CDI if they occurred >3 days after admission and up to 4 weeks following discharge. Trends in the incidence of HA-CDI and CA-CDI were compared using time series with segmented regression and Poisson law.ResultsBetween 2008 and 2015, 28,850 CDI were detected in hospitalized patients. Of these, 4,481 (15.5%) were CA and 24,369 (84.5%) HA-CDI. The annual CA-CDI incidence rate increased by 35.2% from 0.51 to 0.68 per 100,000 population (incidence rate ratio [IRR] per 4-week period, 1.005; 95% confidence interval [CI], 1.004 to 1.006; P < 0.0001) whereas the incidence of HA-CDI remained stable from 6.6 to 7.0 per 10,000 patient-days (IRR per 4-week period, 1.000; 95% CI, 0.999 to 1.000; P = 0.23). There was a significant difference between the trends in incidence of CA-CDI and HA-CDI (IRR, 1.005; 95% CI, 1.004 to 1.006; P < 0.0001). Further analysis showed an inflection point in the incidence of HA-CDI in April 2011 with a reduction in slope (change in trend, IRR, 0.997; 95% CI, 0.995 to 0.999; P = 0.007). No concomitant change was seen in the trend of CA-CDI (change in trend, IRR, 0.997; 95% CI, 0.992 to 1.002; P = 0.2) despite a slight immediate change in level at inflection point (IRR, 1.131; 95% CI, 1.000 to 1.278; P = 0.05).ConclusionBetween 2008 and 2015, the provincial incidence of hospitalized CA-CDI has significantly increased while the incidence rate of HA-CDI has remained relatively stable. Further studies are required to investigate the factors underlying this increase.Disclosures Y. Longtin, Merck: Grant Investigator, Research grant. Becton Dickinson: Grant Investigator, Grant recipient.