Risk of Tendon Injury in Patients Treated With Fluoroquinolone (FQ) Vs Non-Fluoroquinolone Antibiotics for Urinary Tract Infection (UTI).

Background: Fluoroquinolones (FQs) are associated with potential tendon injury but comparative risk versus other antibiotic (non-FQ) options for the same indication has rarely been evaluated.

Objective: Describe the incidence (relative risk) of any tendon injury in patients receiving FQs compared with other (non-FQ) antibiotics for treatment of urinary tract infections (UTIs).

Methods: A retrospective propensity score-weighted cohort study was performed to evaluate the association between FQ antibiotics and tendon injury at two time points (within one month and within six months of use) compared with non-FQ regimens for treatment of UTI. The evaluation was performed using the Merative™ MarketScan^® Research Databases from 2014 to 2020. Adult patients with International Classification of Diseases (ICD)-9/10 coding for UTI were included. Patients with a history of tendon injury or those who received both FQ and non-FQ regimens during the study period were excluded. Propensity score weighting was used to adjust for selection bias due to contributing risk factors, including demographics (age, sex), comorbidities (diabetes mellitus, chronic kidney disease), and concurrent medications (corticosteroids).

Results: Both the 1-month and 6-month cohorts were predominately female and less than 50 years of age. At one month, the incidence of tendon injury was 0.2% in the FQ group and 0.1% in the non-FQ group, and the odds of tendon injury were not estimated to be significantly different between groups (odds ratio [OR] = 1.03, 95% confidence interval [CI] 0.93, 1.32). Odds of tendon injury were also not estimated to be significantly different in the 6-month cohort (OR = 0.98, 95% CI 0.84, 1.05).

Conclusion and relevance: In this population of predominantly young female patients without high incidence of potentially contributing comorbidities, increased risk of tendon injury was not associated with FQ use. Future research is needed to determine whether demographic differences between this and other previously studied populations account for this discordant result.