The applicability of a Clostridium difficile infection (CDI) risk assessment established for patients upon hospital discharge to identify people at high risk of CDI in a primary care population was investigated. The data for this retrospective observational study came from the UK Clinical Practice Research Datalink, which was connected to Hospital Episodes Statistics. The risk index was calculated using the following patient characteristics: age, past hospitalizations, hospital days, and prior antibiotic usage. Individual risk scores were generated by adding points from pre-defined categories for each feature. Researchers used multivariate logistic regression to examine the relationship between risk variables and CDI. In 2008 and 2012, the estimated CDI incidence rate was 4/10,000 and 2/10,000 person-years, respectively. A cut-off for high risk of 7 on an index with a maximum risk of 19 showed sensitivity, specificity, and positive predictive values of 80 percent, 87 percent, and 12 percent, respectively. A high-risk individual had a 35% greater risk of CDI than a low-risk individual. 

A multivariate risk factor analysis revealed that the relative risk scores needed to be reconsidered. The CDI risk score can be used to select research populations for vaccine development trials in the UK primary care community. In this case, reevaluating the relative weights allocated to risk variables might enhance index performance.