December 4, 2013
Despite Previous Reports, Study Finds No Fluoroquinolone/Eye Disorder Link

Copenhagen, Denmark—A new Danish study is calling into question whether the use of fluoroquinolones is linked to a higher risk of retinal detachment, as suggested by earlier research.

A nested case control study published last spring in the Journal of the American Medical Association (JAMA) found that use of fluoroquinolones was strongly associated with retinal detachment, reporting a 4.5-fold increased risk for ongoing exposure. That article suggested that the antibiotics’ effect on connective tissue could be a factor in development of the acute eye disorder.

The new study, also appearing in JAMA in November, found no such link, however.

Bjorn Pasternak, MD, PhD, of the Statens Serum Institut, Copenhagen, Denmark, and colleagues used data from a nationwide register to investigate whether oral fluoroquinolone use was associated with increased risk of retinal detachment. Included in the review was information about 748,792 episodes of fluoroquinolone use and 5,520,446 control episodes of nonuse, including data on participant characteristics, specific antibiotics used, and cases of retinal detachment with surgical treatment.

Most of the study subjects used ciprofloxacin, 88.2%. Ofloxacin (9.2%), fleroxacine (1.2%), moxifloxacin (0.8%), and others in the antibiotic class (0.7%) were used in a minority of cases.

Of 566 patients with retinal detachment, 72 had been exposed to fluoroquinolones—five had current use (Days 1-10), seven had recent use (Days 11-30), 14 had past use (Days 31-60), and 46 had distant use (2-6 months). Another 494 cases occurred among patients not exposed to fluoroquinolones.

Analysis of the data indicated that fluoroquinolone use compared with nonuse was not associated with increased risk of retinal detachment, the authors report.

The crude incidence rate was 25.3 cases per 100,000 person-years in current users, 18.9 in recent users, 26.8 in past users, and 24.8 in distant users compared with 19.0 in nonusers. Compared with nonuse, fluoroquinolone use was not associated with a significantly increased risk of retinal detachment, with adjusted RRs of 1.29 (95%CI, 0.53-3.13) for current use; 0.97 (95%CI, 0.46-2.05) for recent use; 1.37 (95%CI, 0.80-2.35) for past use; and 1.27 (95%CI, 0.93-1.75) for distant use, according to the results.

In the study, the absolute risk difference, estimated as the adjusted number of retinal detachment cases per 1,000,000 treatment episodes, was 1.5 (95%CI, –2.4-11.1) for current use.

While, because of limited power, the study can only rule out more than a three-fold relative increase in the risk of retinal detachment associated with current fluoroquinolone use, the authors note, they add that any differences in absolute risk are unlikely to have any clinical significance.

In fact, in terms of absolute risk, current use of fluoroquinolones would, in the worst-case scenario, account for no more than 11 additional cases of retinal detachment per 1,000,000 treatment episodes, they point out.

In an accompanying editorial, Allan S. Brett, MD, of the University of South Carolina School of Medicine in Columbia, says “there is no way to know with certainty which of the two studies is more accurate,” although he notes that the cohort in the most recent research was the entire Danish population, compared to the Canadian study, which only looked at British Columbia residents who had visited ophthalmologists.

Brett also suggests that neither study was likely to change prescribing patterns at this point.

“For the physician caring for an inpatient with an indication for fluoroquinolone therapy, retinal detachment should not cross the physician's mind. But the next time an outpatient with no good indication for a quinolone asks for one 'because I got better last time I took it,' the physician might mention a remote possibility of retinal detachment among the many reasons for declining the request,” he advises.

U.S. Pharmacist Social Connect