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