Big Regional Differences in Glaucoma Diagnosis Found

April 23, 2012

By Aparna Narayanan

NEW YORK (Reuters Health) Apr 20 - A new analysis of Medicare records finds dramatic differences across the United States in rates of new glaucoma diagnoses, suggesting the eye disease is likely being overdiagnosed in some regions and underdiagnosed in others, researchers said.

Looking at all Medicare claims for a seven-year period, the team found glaucoma rates had risen slightly overall, but that people in New England or the Mid-Atlantic states had about 30% higher odds than people in the Southeast of being diagnosed with glaucoma -- and some 70% higher chances of being diagnosed with suspected glaucoma.

"We're seeing that potentially both physicians and patients in (predominantly rural) areas are not getting the healthcare that would be obtained in a large urban setting," such as the New York-Baltimore-Philadelphia area, said Dr. Harry Quigley, from the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, who worked on the study.

The findings were published online April 4 in Ophthalmology.

Dr. Quigley said lower diagnosis rates in less-urbanized settings may stem from different physician styles in examining patients and detecting glaucoma or fewer eye-care visits by patients, or both.

More than 2.2 million Americans are estimated to have glaucoma, which can lead to blindness. For the new study, researchers examined a random sample of Medicare claims submitted by ophthalmologists, optometrists and outpatient surgery centers. They looked at claims data from 2002 through 2008, across nine large geographic regions and 179 subregions.

The researchers report that the overall prevalence of diagnosed glaucoma increased from 10.4% in 2002 to 11.9% by 2008, largely owing to an increase in suspected open-angle glaucoma diagnoses (from 3.2% to 4.5%; p<0.001). The relative prevalence of diagnosed open-angle glaucoma compared with diagnosed angle-closure glaucoma was 32 to 1, the authors say.

From that data, they concluded that acute glaucoma was seriously underdiagnosed.

The New York City area had the highest rates of the condition of all the 179 subregions, which indicated that physicians there were either overdiagnosing it or doing a better job of detecting it. The low rates of diagnosis in all the other areas suggest it's the latter, researchers said, and New York is doing a better job at detection.

"Healthcare providers need to be performing gonioscopy on a regular basis," said Dr. Sandra Cassard, the study's lead author.

Women were more likely than men to have the condition, the study found. And rates of most forms of the condition rose until age 80, and then fell thereafter.

"This may indicate lack of continuity in care among the very old," Dr. Cassard, who is also with the Wilmer Eye Institute, told Reuters Health. "Seniors need to be encouraged to visit eye-care professionals," especially those over age 80 who may not be making the recommended yearly office visit, she said.

Only about half of the beneficiaries made an office visit to an optometrist or ophthalmologist in 2008.

Blacks, Hispanics and Asians were less likely than non-Hispanic whites to have an eye exam, but they also showed the highest rates of glaucoma and greater risk of developing it.

While failure to detect glaucoma early can lead to blindness, overdiagnosis presents its own challenges to physicians, the researchers noted.

According to Dr. Shakeel Shareef, an associate professor of ophthalmology at the University of Rochester Medical Center, about 30% of his glaucoma referrals turn out not to have the condition. "But at least the referring doctor did not subject someone to treatment for life on medications" that were unnecessary, he told Reuters Health.

In many cases, patients "don't necessarily need to be treated but they need to be monitored" for risk of developing the condition, said Dr. Shareef, who was not involved in the study.


Ophthalmology 2012.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.