Effectiveness of interventions to promote screening for diabetic retinopathy

Increasing patient and clinician awareness and improving access to health care can encourage people with diabetes to seek annual eye exams, which help prevent a serious complication called retinopathy, according to a new systematic review of studies.

However, the studies showed that these tactics are less successful when conducted among ethnic minorities or in rural areas, according to researchers led by Xuanping Zhang, Ph.D., of the Centers for Disease Control and Prevention.

Minorities have a higher prevalence of diabetes than whites do, according to the U.S. Agency for Healthcare Research and Quality. Some minority groups also have much higher rates of diabetes-related complications, in some instances by as much as 50 percent more than the total population.

Diabetic retinopathy occurs when chronically elevated blood-sugar levels damage small blood vessels in the eye. The disease might cause very few symptoms before vision loss begins, and it remains the leading cause of new-onset blindness among American adults.

Careful control of blood glucose and blood pressure can reduce the risk of these eye problems, and in more advanced cases, laser surgery can often preserve vision.

The American Diabetes Association recommends dilated eye exams at least once a year for most people with the disease. However, in 1998, only 47 percent of U.S. patients followed this advice. One of the nation's health objectives is to increase this figure to 75 percent by 2010.

The new systematic review provides evidence on effective ways to promote annual screenings for diabetic retinopathy. It appears in the October issue of American Journal of Preventive Medicine .

The review includes 48 studies with more than 160,000 participants from the United States, Australia, the United Kingdom, Israel, Saudi Arabia and other developed countries. Twelve of the studies are randomized controlled trials, which many consider the most reliable.

“In all randomized controlled trials but one, interventions achieved statistically significant increases in retinal screening rates in the intervention group compared to the control group,” Zhang said. The other 36 studies also generally demonstrated positive effects.

The studies looked at a wide range of approaches to promoting eye exams — some emphasizing patients or populations, and others focusing on health care providers. Data showed that the following interventions are effective:

• Increasing patient and provider awareness of diabetic retinopathy
• Improving access to health care
• Introducing computer-based registration or reminder systems
• Collaboration among local organizations that provide retinal screening
• Developing a community-based health care system

Evidence also suggested that these approaches are more likely to succeed when the interventions are part of a multifaceted program.

The authors said that a great deal of variety exists in the studies regarding characteristics of participants, types of activities examined and length of follow-up — making it difficult to synthesize the results of all the studies.

In particular, health care systems can differ considerably, the authors said. “Thus, specific interventions may [only] be applicable to certain settings, regions or countries.”

“We've spent a lot of time trying to educate patients and care providers on the importance of eye exams,” said Jerry Cavallerano, O.D., of the Joslin Diabetes Center in Boston. Yet too many at-risk people still do not seek regular retinal evaluations.

“We have to start thinking about other ways of reaching people,” Cavallerano said. “One way would be to bring eye care to a person, rather than wait for a person to come to care.”

The Joslin Vision Network Diabetes Eye Care Program uses telemedicine for its outreach efforts. Local clinicians can use high-tech digital cameras to photograph patients' retinas. They then transmit the images electronically to specialists for analysis and treatment recommendations.

The program is now in use at more than 50 sites across the country, including clinics operated by the Department of Veterans Affairs, the Indian Health Service and the Department of Agriculture.

“Focusing an intervention on high-risk subgroups is a valid strategy for improving overall use,” the review authors said.

Regardless of patient characteristics, the American Diabetes Association Web site makes one fact very clear. “Having your regular doctor look at your eyes is not enough, nor is having your eyeglass prescription tested by an optician. Only optometrists and ophthalmologists can detect the signs of retinopathy.”

American Journal of Preventive Medicine : Contact the editorial office at (858) 457-7292 or [email protected]

Zhang X, et al. Effectiveness of interventions to promote screening for diabetic retinopathy. Am J Prev Med 33(4), 2007.