While fluoroquinolones may slightly increase the risk of aortic aneurysm or aortic dissection (AA/AD), the overall benefits of these medications, when used appropriately, may outweigh this potential risk, according to the findings of a recently published cohort study.

The observational study aimed to determine the association between fluoroquinolone use and the risk of AA/AD while taking into account potential confounding by indication and bias due to differences in surveillance. Data on patients within a US commercial claims database between January 1, 2003, and September 30, 2015 were analyzed to identify 2 pairwise 1:1 propensity score-matched cohorts.

These cohorts were: patients ≥50 years old diagnosed with pneumonia for ≤3 days prior to initiating therapy with a fluoroquinolone or azithromycin and patients ≥50 years old diagnosed with a urinary tract infection (UTI) for ≤3 days prior to initiating therapy with a fluoroquinolone or trimethoprim/sulfamethoxazole.

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Hazard ratios (HRs) were estimated while 85 baseline confounders were controlled for. The main outcome of the study was hospitalization for AA/AD that occurred within 60 days of initiating treatment. “In a secondary analysis, patients receiving fluoroquinolones were compared with those receiving amoxicillin, both with and without considering baseline aortic imaging, to address differences in detection of AA/AD before antibiotic use,” the study authors added.

The authors reported that the patient characteristics of the pneumonia cohort (n=279,554) were well matched to those of the patients in the UTI cohort (n=948,364) after propensity score matching. Findings of the study revealed an increased rate of AA/AD among patients who initiated fluoroquinolones compared with those who initiated azithromycin (HR, 2.57; 95% CI, 1.36-4.86; incidence, 0.03% for fluoroquinolones vs 0.01% for azithromycin) in the pneumonia cohort (n=139,772 pairs). Conversely, no rate increase of AA/AD was observed for initiators of fluoroquinolones compared to trimethoprim/sulfamethoxazole (HR, 0.99; 95% CI, 0.62-1.57; incidence, <0.01% for both groups) in the UTI cohort (n=474,182 pairs).

In the secondary analysis, which used amoxicillin as a comparator (n=3,976,162 pairs), results were found to be consistent with those from earlier studies (HR, 1.54; 95% CI, 1.33-1.79; incidence, <0.01% in both groups). The authors stated, “Requiring baseline imaging in this cohort (n=542,649 pairs) to address surveillance bias attenuated the increased rate (HR, 1.13; 95% CI, 0.96-1.33; incidence, 0.06% for fluoroquinolones vs 0.05% for amoxicillin).”

According to the results of this cohort study, fluoroquinolones were found to be associated with an increased relative rate of AA/AD in the pneumonia cohort but not within the UTI cohort. “This increased rate raises the possibility that fluoroquinolones may increase the risk of AA/AD, but residual confounding and surveillance bias cannot be ruled out,” the authors stated. They concluded, “The rates of AA/AD were low across cohorts (ie, <0.1%), and the benefits of choosing fluoroquinolones for treatment, when appropriate, may outweigh a small potential increased risk of AA/AD.”

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.


Gopalakrishnan C, Bykov K, Fischer MA, Connolly JG, Gagne J, Fralick M. Association of fluoroquinolones with the risk of aortic aneurysm or aortic dissection. Published online September 8, 2020. JAMA Intern Med. 2020. doi:10.1001/jamainternmed.2020.4199.

This article originally appeared on MPR