In the December 2005 issue of Diabetes Care, a group of investigators described the impact of case management on 149 people with diabetes.

Participants were randomly assigned to receive intensive diabetes case management or their usual medical care. All participants had retinal photographs and blood drawn to measure glycated hemoglobin (A1C) at regular intervals. They were followed for 2 years.
Although there was no difference in the progression of retinopathy once the disease was present, those who received case management and had no signs of retinopathy at the beginning of the study were less likely to develop retinal changes during the study period. Overall, participants who were in the "usual care" group were more than five times as likely to show changes indicative of retinopathy as those who received case management.

The study shows that "a relatively short duration of case management instituted before the onset of clinically identifiable retinopathy significantly diminished the risk of developing retinopathy in patients with type 2 diabetes," the group concludes.

Source: Diabetes In Control: Pettitt DJ, Okada Wollitzer A, Jovanovic L, et al.: Decreasing the risk of diabetic retinopathy in a study of case management: The California Medi-Cal Type 2 Diabetes Study. Diabetes Care 28:2819–2822, 2005.