Prevalence of DRP and DME Among Type 1 Diabetics Treated With Long-term Intensified Insulin Therapy

Purpose: This study is designed to evaluate the prevalence of different stages of diabetic retinopathy and diabetic macular edema among patients suffering from type 1 diabetes for 5 to 25 years and have been treated with intensified insulin therapy aiming near-normal blood glucose levels for the whole duration of disease.

Objectives: The primary objective is to examine the prevalence (percentages) of the stages of diabetic retinopathy (DR) and diabetic macular edema (DME) within one cross-sectional examination. Key secondary/exploratory objectives are the prevalence (percentages) of the stages of diabetic macular edema (DME), the means of individual average 5year-/10year-/15year-/20year-/25year-HbA1c value (%) as a measure for long-term glycemic control, the means of individual average 5year-/10year-/15year-/20year-/25year-blood pressure (mmHg) as a measure for long-term blood pressure control, mean BCVA score, mean contrast sensitivity score, mean NEI-VFQ 25 score (for further details see section Objectives).

Study design: Non-interventional cross-sectional investigator initiated study. The study will be conducted at Vista Klinik Binningen/Switzerland (ophthalmological evaluations) and the Department of Endocrinology of the University Hospital Basel/Switzerland (patient recruitment).

Study population: All patients with DM Type 1 with a least 5 years and maximum 25 years disease duration and intensified insulin therapy for the whole duration of disease, who are currently in follow-up for their DM1 at Department of Endocrinology of the University Hospital Basel/Switzerland. In order to prevent selection bias, patients will be screened for enrollment consecutively. For In-/exclusion criteria see section Eligibility.

Investigational and reference therapy: None.

Assessments:

• Visual acuity measurements using the ETDRS-like testing charts at a test distance of 4 meters
• Contrast sensitivity
• Ophthalmic examinations (slit lamp exam with fundus biomicroscopy, intraocular pressure)
• High resolution optical coherence tomography (Spectralis-OCT)
• Stereoscopic fundus photography
• Fluorescein angiography
• NEI-VFQ 25 (25-item National Eye Institute Vision Function Questionnaire)

Inclusion criteria

• Male or female patients >18 years of age who have signed an informed consent
• Patients with type 1 diabetes mellitus diagnosed between 5 and 25 years prior to screening who were on intensified insulin therapy (multiple daily insulin injections or insulin pump) from the beginning of the disease.

Exclusion criteria

• Patients with hypertension and a change in antihypertensive treatment within 2 months pre-enrollment should not be enrolled unless blood pressure is maintained for at least 1 month below 160/100 mm Hg by antihypertensive treatment.
• Patients with a history of chronic renal failure requiring dialysis or kidney transplantation if there is a risk for the patient to perform fluorescein angiography (discretion of the endocrinological investigator).
• Pregnant or nursing (lactating) women, where pregnancy is defined as the state of a female after conception and until the termination of gestation, confirmed by a positive hCG laboratory test (>5 mIU/ml).
• History of allergy to fluorescein.
• Inability to obtain fundus photographs, fluorescein angiograms or OCT images of sufficient quality to be analyzed and graded.
• Inability to comply with study procedures.