Research: Similar endophthalmitis rates for generic, branded topical antibiotics

This article was reviewed by Tracy W. Krick, MD

When the postoperative rates of endophthalmitis between brands and types of topical antibiotics are compared, no single antibiotic has clear superiority over another.

This finding may lead to an opportunity for patients to cut costs by using less expensive antibiotics after cataract surgery.

Most cataract surgeons prescribe perioperative topical antibiotics to prevent infections after procedures. Numerous options are available, and their costs also vary widely.

Related: Battling endophthalmitis: New bugs, new technologies, new drugs​ ​

Interestingly, there is little information regarding the rates of endophthalmitis infections associated with the various topical antibiotics.

In light of that, Tracy W. Krick, MD, and associates compared the postoperative rates of endophthalmitis among patients who had been treated with different types of antibiotics after cataract surgery.

The investigators also sought to determine prescribing patterns and the costs associated with the topical antibiotics.

Study design
This study was a cross-sectional analysis of Medicare patients who had Part D coverage and underwent cataract surgery in 2016. The investigators analyzed the rates of endophthalmitis within 90 days after surgery.

The results showed that endophthalmitis rates were strikingly similar in almost 600,000 patients using different types of topical antibiotics: 0.10% with fluoroquinolones, including ofloxacin, moxifloxacin, and besifloxacin, which accounted for about 35%, 15%, and 10.7%, respectively, of patients; 0.09% with polymyxins; and 0.12% with aminoglycosides, Krick reported.

Related: Endophthalmitis detection by whole genome sequencing and qPCR​ ​

“The rates of endophthalmitis were low regardless of the type of topical antibiotics prescribed. Overall, there was no clinically significant difference in the rates of endophthalmitis among patients prescribed different classes of antibiotics,” she said.

The investigators found that 66.6% of drugs were generics and the remainder were brand-name drugs.

Again, the rates of endophthalmitis were nearly the same, at 0.07% and 0.08%, respectively. “Overall, this represents no clinically significant difference between the generic and branded drugs,” Krick said.

Substantial savings with generics
One major difference between the 2 types of medications was cost, with branded drugs
accounting for 80% of the cost of the antibiotics, according to Krick:

“The total cost of topical antibiotics prescribed for cataract surgery in 2016 was about $42.8 million. Of this number, branded moxifloxacin and besifloxacin commanded the lion’s share, at over $21 million and $12 million, respectively.”

Related: Topical moxifloxacin: Best choice before cataract surgery?​

The investigators calculated that if generic drugs were substituted for the directly equivalent branded prescriptions, the savings would exceed a whopping $14 million.

“If one is willing to make substitutions among the different types of fluoroquinolones, the potential annual savings are ever greater,” Krick said. With about $35 million spent on ciprofloxacin, gatifloxacin, levofloxacin, moxifloxacin, and besifloxacin currently, substituting generic for the other types of fluoroquinolones would save more than $29 million in 1 year.

“Our initial analyses did not show a clear superiority of 1 topical antibiotic over another. However, we could not account for the use of intracameral antibiotics, and the study had limitations of claims data, which lack granularity,” Krick said.

In recent years, intraoperative intracameral antibiotics emerged as an alternative to perioperative topical antibiotics.

The 2013 European Society of Cataract and Refractive Surgeons guidelines for prevention of endophthalmitis and the American Academy of Ophthalmology’s 2016 Cataract Preferred Practice Patterns concluded that intracameral antibiotics are an effective method of endophthalmitis prophylaxis.

​​ Related: ASCRS 2020: Assessing effectiveness of intracameral phenylephrine/ketorolac post-cataract surgery

A growing body of evidence, including a prospective treatment study by the ESCRS Endophthalmitis Study Group, found that intracameral antibiotics more effectively reduce the risk of endophthalmitis compared with topical antibiotics.

“Our study was unable to evaluate the use and costs of intracameral antibiotics due to different payment mechanism for drugs used during surgery versus outpatient use in the Medicare system,” Krick commented. “[Although] there is a potential to save a great deal of money by prescribing generic brands over brand-name topical antibiotics, further research is needed to elucidate the best practice that would improve the value of care delivered to patients.”

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Read more by Lynda Charters

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Tracy W. Krick, MD
e:ywang148@jhmi.edu
Krick has no financial interests in this subject matter. She is a resident at the Wilmer Eye Institute at Johns Hopkins Medicine in Baltimore, Maryland.