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Intensive therapy reduces incidence, cost of ocular surgery in type 1 diabetes
Intensive insulin therapy reduced the risk of any diabetes-related ocular surgery by 48%.
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Intensive insulin therapy significantly reduced the long-term risk of ocular surgery in patients with type 1 diabetes, according to a study.
Data were culled from the Diabetes Control and Complications Trial (DCCT) and the Epidemiology of Diabetes Interventions and Complications (EDIC) study.
“This study ... had the remarkable finding that, even after the blood sugar control came to be the same, there continued to be a benefit to the group that had received intensive early glycemic control,” Lloyd Paul Aiello, MD, PhD, of the DCCT/EDIC Research Group, told Ocular Surgery News. “Not only that, this benefit lasted for decades. That was a major finding, demonstrating not only how important it is for patients to achieve better glycemic control when they have diabetes, but that the earlier you achieve this, the better off you are in the long term.”
The report was published in The New England Journal of Medicine.
Study design and metrics
The DCCT, conducted between 1983 and 1989, included 1,441 patients with type 1 diabetes; 711 patients were randomized to intensive therapy, and 730 patients were randomized to conventional therapy.
Treatment and follow-up in the DCCT ended in 1993. Average duration of treatment was 6.5 years. Patients in the conventional therapy group were then offered intensive therapy.
Patients were enrolled in the EDIC study in 1994. The study included 1,375 of 1,428 surviving DCCT participants (96%).
“All of the EDIC patients were part of the DCCT study. There were only a small percentage that did not continue from the DCCT into the EDIC study. But for these studies, the follow-up percentage was very high,” Aiello said.
Patients self-reported ocular surgical procedures annually. Structured interviews were conducted to acquire details of patients’ ocular procedures.
All operations were classified as substantially diabetes-related or not substantially diabetes-related. The main categories of diabetes-related operations were cataract extraction, vitrectomy or retinal detachment surgery, and glaucoma surgery.
“Outside of those three, the numbers were too small to find statistically significant changes,” Aiello said.
Laser therapy and anti-VEGF injections for macular disease or proliferative retinopathy were not classified as surgical procedures.
The cost of ocular surgery was calculated in 2010 U.S. dollars using the medical care Consumer Price Index, factoring in an annual inflation rate of 3%.
Data were obtained for up to 27 years after the start of the DCCT; median follow-up was 23 years.
Results and conclusions
One hundred thirty ocular operations were performed on 63 of 711 patients in the intensive therapy group (8.9%), and 189 operations were performed on 98 of 730 patients in the conventional therapy group (13.4%); the between-group difference was statistically significant (P < .001).
Adjusted data showed that intensive therapy reduced the risk of any diabetes-related ocular surgery by 48% (P < .001) and the risk of any ocular surgery by 37% (P = .01).
Forty-two patients in the intensive therapy group and 61 in the conventional therapy group underwent cataract extraction (P = .002).
Twenty-nine patients in the intensive therapy group and 50 in the conventional therapy group underwent vitrectomy, retinal detachment surgery or both (P = .01).
Nine patients in the intensive therapy group and 14 in the conventional therapy group underwent glaucoma surgery.
Two patients in the intensive therapy group and three in the conventional therapy group had corneal surgery.
Inflation-adjusted costs in 2010 dollars for all cataract extraction, vitrectomy and glaucoma operations totaled $429,469 in the intensive therapy group and $634,925 in the conventional therapy group, a difference of 32%.
“Early better blood sugar control had a very clear beneficial effect on reducing the risk of ocular surgery,” Aiello said. “Benefits of good blood sugar control also include reduced progression of retinopathy, less need for laser and less progression of kidney disease, nerve disease and cardiovascular disease.”
Limitations included ocular surgery being self-reported by patients and a focus on type 1 diabetes as opposed to type 2 diabetes, the authors said. – by Matt Hasson
- Reference:
- DCCT/EDIC Research Group, et al. N Engl J Med. 2015;doi:10.1056/NEJMoa1409463.
- For more information:
- Lloyd Paul Aiello, MD, PhD, can be reached at Beetham Eye Institute, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215; email: lpaiello@joslin.harvard.edu.
Disclosure: Aiello reports no relevant financial disclosures.