Long-term progression of retinopathy after initiation of insulin therapy in Type 2 diabetes: an observational study.
OBJECTIVE
Universal worsening of retinopathy after starting insulin therapy in Type 2 diabetes has been suggested in previous work.


METHODS
We studied 294 such patients for up to 5 years to evaluate retinal changes and define the factors affecting progression of retinopathy. Yearly retinal photographs were graded using the EURODIAB system.


RESULTS
Prior to insulin therapy, 26.2% (77/294) of the patients had minimal non-proliferative diabetic retinopathy (NPDR), 3.7% (n=11) had moderate NPDR and 1% (n=3) had severe NPDR. Over the first 3 years of insulin therapy, significant progression occurred in 36 subjects (12.6%). This comprised 5/193 (2.6%) without any retinopathy at baseline, 22/77 (28.5%) with minimal NPDR and 6/11 with moderate NPDR (54.5%) (chi2=56.1, p<0.001). In a control group of 70 patients who remained on oral hypoglycaemic agents, nine patients had significant worsening of retinopathy over 3 years. Over 5 years, 22/127 (17.3%) of patients (9/95 without and 13/32 with retinopathy at baseline [chi2=16.2, p<0.001]) had significant progression of retinopathy. Higher baseline HbA1c (p=0.002) and lower initial decrease in HbA1c (p=0.007) were each independent predictors of greater retinopathy progression over this period. There was no significant worsening of visual acuity in patients whose retinopathy progressed.


CONCLUSIONS
After initiation of insulin treatment in Type 2 diabetes, clinically significant worsening of retinopathy over a 3-year period was uncommon in those with no retinopathy (2.6%) but occurred in 31.8% of patients with any retinopathy at baseline. The risk of serious worsening of retinopathy after insulin therapy is started in all patients with Type 2 diabetes may have been previously overestimated.
Department of Medicine, The Medical School, University of Newcastle, Newcastle Upon Tyne, UK. csarun2003@yahoo.co.uk
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Arun
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Pandit
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Taylor
D000284:Administration, Oral; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy*; D003930:Diabetic Retinopathy / Q000139:chemically induced / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D015994:Incidence; D007328:Insulin / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D014792:Visual Acuity
D007004:Hypoglycemic Agents; D007328:Insulin