High risk of Clostridium difficile infection among spinal cord injured patients after the use of antibiotics commonly used to treat urinary tract infections

Aim — To characterize the use of common urinary tract infections (UTI)‐relevant antibiotics after an SCI and determine the risk of Clostridium difficile infection (CDI) from these antibiotics.

Methods — We used routinely collected data from Ontario (Canada) to conduct a retrospective, cohort study. We identified people >18 years of age with a traumatic SCI between April 2003 and March 2017. The primary exposure was an outpatient UTI‐relevant antibiotic prescription during our observation period, and the primary outcome was evidence of a CDI. An adjusted cox proportional hazards model was used, and antibiotic exposure was modeled as a categorical, time‐varying variable based on whether the patient likely had a UTI or not.

Results — We identified 2528 people with SCI; 1642 (65%) were exposed at least once to an antibiotic of interest. The most commonly prescribed UTI‐relevant antibiotic was fluoroquinolone (34%). Most patients did not have investigations for a UTI before the use of any of the different antibiotic classes. A small number of patients (5%) used chronic (>3 months) UTI‐relevant antibiotics. The overall proportion of patients diagnosed with CDI was 7.4% (9.3/10 000 patient‐days). The adjusted hazard ratio for CDI within 30 days was 3.5 (95% confidence interval, 1.9–6.7, p < .01) if they were exposed to a UTI‐relevant antibiotic likely associated with a UTI, which was similar to the risk from UTI‐relevant antibiotics which may not have been for a UTI.

Conclusions — The rate of CDI is high in this population and outpatient antibiotics that are commonly used for UTIs are a significant risk factor for CDI.