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Intensified insulin therapy education slows retinopathy development in type 1 diabetes

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February 1, 2019

Adults with long-term type 1 diabetes who received education for intensified insulin therapy self-management beginning at diagnosis had improved glucose control and low risk for diabetic retinopathy, according to findings published in Diabetes Research and Clinical Practice.

“Current treatment guidelines for people with type 1 diabetes recommend a target HbA1c of 7% (53 mmol/mol) or less for adults. Intensive patients’ (and physicians’) education has the potential to achieve this target while reducing the risk for severe hypoglycemia,” Henryk Zulewski, MD, of the division of endocrinology, diabetes and clinical nutrition and department of research at the University Hospital Basel in Switzerland, and colleagues wrote. “As the true impact of such an improved diabetes control on the development of [diabetic retinopathy] is not well-known, the aim of our study was to analyze the prevalence of [diabetic retinopathy] in those patients who received education-based intensified diabetes therapy from the start.”

Zulewski and colleagues recruited 151 adults with type 1 diabetes for at least 5 years (mean age, 39.9 years; 35.1% women; median HbA1c, 7.4%; mean diabetes duration, 14.3 years) from the Clinics of Diabetes and Endocrinology of the University Hospital Basel and the University Hospital Zurich in Switzerland between August 2010 and May 2014. Participants underwent ophthalmologic examinations with ETDRS 7-field color fundus photographs and fluorescein angiography. HbA1c was measured and retrospectively collected from the time of diabetes diagnosis to the ophthalmologic examinations. Mean HbA1c was determined for each year, and HbA1c years were calculated as the sum of HbA1c amount above 6% multiplied by number of years.

The researchers used four classifications of diabetic retinopathy. Stage 0 meant no apparent retinopathy, stage 1 meant mild nonproliferative diabetic retinopathy, stage 2 meant moderate nonproliferative diabetic retinopathy, stage 3 meant severe nonproliferative diabetic retinopathy and stage 4 meant proliferative diabetic retinopathy.

No signs of diabetic retinopathy were present in 39% of the participants based on the 7-field photography, whereas 28% presented with mild stage 1 diabetic retinopathy. Stage 4 diabetic retinopathy was reported in only one participant. Quality of diabetes control (P = .003), diabetes duration (P < .001) and HbA1c years (P < .001) all correlated to the maximum stage of diabetic retinopathy, although the researchers noted that HbA1c years had the strongest correlation. The apparent presence of diabetic macular edema was reported in 6.6% of participants, with 0.7% exhibiting a severe strain, which the researchers noted was a “sight-threatening sign of [diabetic retinopathy].”

“The implementation of an education-based intensified insulin therapy in routine diabetes care is not only associated with a better diabetes control, but also with reduced risk for the development of diabetic retinopathy,” the researchers wrote. “The glucose exposure over time expressed as HbA1c years is the best predictive parameter for the development of [diabetic retinopathy].” – by Phil Neuffer

Disclosures: The authors report no relevant financial disclosures.

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