March 2010

 

OPHTHALMOLOGY NEWS

 

Stemming the visual tide for type 1 diabetes


by Maxine Lipner Senior EyeWorld Contributing Editor

   

New results show reduction in visual problems

There was a time when visual impairment was an all too common result of type 1 diabetes. However, those diagnosed with the disease more recently are much less likely to suffer visual consequences, according to Ronald Klein, M.D., professor of ophthalmology and visual sciences, University of Wisconsin, Madison. Results published in the October 2009 issue of Ophthalmology indicate that for those most recently diagnosed with the disorder there is a lower prevalence of visual impairment than for those who were contending with the disease years earlier.

Prior to launching the study investigators had an inkling that things might be improving for diabetic patients. “We knew that glycemic control and blood pressure control were improving,” Dr. Klein said. “Also, there were programs that had been set up in the early 90s, screening and education programs attempting to translate the results of clinical trials into practice, so we had a hunch that things would be getting better.” Dr. Klein’s own experience seemed to indicate this as well. “In clinical practice I seemed to see less severe retinopathy for a given number of years of diabetes than I did 25 years earlier,” he said.

Epidemiologic study

Included in the population-based, longitudinal study were 955 patients who had been diagnosed with type 1 diabetes by the age of 30. These patients lived in 11 county areas in southern, southwestern, and south-central Wisconsin. Over the course of the study, patients underwent five eye examinations, the earliest in a period from 1980-1982 and the latest in a period from 2005-2007. The patients themselves were grouped as being diagnosed with diabetes in one of four time periods, prior to 1960, 1960-1969, 1970-1974, and 1975-1979.

Over the 25-year study period there were two key findings. “One finding was that the estimated annual incidence appeared to be dropping in the second half of the study, the last 13 years, compared to the first half of the study,” Dr. Klein said. “The second finding was that the estimated prevalence of visual impairment for those who were diagnosed in later periods was lower than for people of the same [disease] duration diagnosed in earlier periods.” For example, people who had been diagnosed just before the study began during the period from 1975-1980 had significantly lower prevalence of visual impairment after having the disease for 20-24 years than those who had been diagnosed in earlier periods.

The technology factor

Dr. Klein theorizes that improved medical technology may be playing a pivotal role in this. “When we started the study most people checked their glycemic levels by doing spot urine tests,” he said. “However, at the 25-year period most people were using home blood glucose monitoring three times a day or more, so the technology that enabled them to do that was a big factor.”

In addition to keeping a tighter rein on glucose levels, technology has improved on the treatment front as well. “Insulin pumps have helped with more continuous delivery of insulin for better control, and the new drugs that have come on the market for treating blood pressure like the ACE [angiotensin-converting enzyme] inhibitors and the receptor blockers have also helped,” Dr. Klein said. “I think that there’s more awareness on the part of physicians as well as patients that control matters.”

Dr. Klein sees the study as imparting good evidence that public policy and public health care delivery with regard to diabetes has benefited individuals. “It’s a demonstration from the bench all the way to the delivery of health care showing the success of intervention,” he said. “It’s a good public health message.”

Going forward, Dr. Klein acknowledges that there is still a long way to go. “There is still a lot of need,” he said. “There are a lot of people who have complications and severe hypoglycemic reactions that occur as a result of intensive insulin treatment.” Controlling such reactions is one area in which Dr. Klein envisions improvement in the future. “I think that there is a need to get better glycemic control and to ultimately prevent Type 1 and Type 2 diabetes from occurring,” Dr. Klein said. “That’s probably the best thing that could happen.”

Editors’ note: Dr. Klein has financial interests with AstraZeneca (London).

Contact information

Klein: kleinr@epi.ophth.wisc.edu

Stemming the visual tide for type 1 diabetes Stemming the visual tide for type 1 diabetes
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