New research reports a 76% success rate at five years for primary penetrating kerotoplasty (PKP), which is significantly lower than the 90% success rate that’s typically reported in current US studies.

“Anecdotally and in the clinic, we were seeing a lot of patients who had corneal transplants that weren’t doing as well as what was reported in the literature,” says researcher Sumayya Ahmad, MD, of the Icahn School of Medicine of Mount Sinai, New York.

While Dr. Ahmad and her research team noticed US studies were citing 90% success rates after five to 10 years, they were personally observing many failed and multiple transplants.

“We felt like it wasn’t an accurate presentation of what was actually happening on the ground, so we decided to do a claims analysis where we looked at medical data to see if the patients getting these transplants were getting repeat transplants, as we suspected, or were failing over time.”

The investigation, published in the Canadian Journal of Ophthalmology, analyzed records spanning 2011 to 2017 from a large commercial insurance database of 10 million patients. The team used the data to track the real-world, long-term survival rate and risk factors of PKP in the United States. The study also conducted further analysis to determine failure rate and risk factors impacting graft outcomes.

From the data, researchers pinpointed 596 primary PKPs performed over the seven-year period. The investigators reported the three-year survival rate was 78%. At five years, the survival rate was slightly lower at 76%, and lower still at seven years at 73%.

Dr. Ahmad attributes part of the discrepancy between her study’s findings and the more favorable results from previous literature to the fact other investigations may only publish successful outcomes, have more compliant patients, or authors may work at established, specialty centers, unlike clinics.

Another factor she cites is that unlike countries such as Australia, the UK and parts of Europe, the United States doesn’t have a graft registry, which monitors and tracks patients over time.

“If you compare our results with those in Australia’s graft registry, they’re very similar,” Dr. Ahmad says.

Her advice is to think more carefully about recommending corneal transplants to patients. “Their success rates aren’t as good as we think. For certain patients, it’s an awesome procedure, but for other patients, it might not be.”

As such, keeping patients in specialty contact lenses might be preferable in some cases, Dr. Ahmad says.