Sight-threatening retinopathy is associated with lower mortality in type 2 diabetic subjects: a 10-year observation study.

Aims: To study associations between diabetic retinopathy and development of stroke, myocardial infarction and death in type 2 diabetic patients.

Methods: During a 10-year observation period, 363 type 2 diabetic patients (diagnosis > or =30 years of age) attending an outpatient clinic were studied regarding the prevalence and incidence of retinopathy and associated risk factors, i.e., (HbA(1c), blood pressure, albuminuria, plasma creatinine, age, sex and diabetes duration) in relation to the development of myocardial infarction, stroke and death. The degree of retinopathy was classified as no retinopathy, background or sight-threatening retinopathy, i.e., clinically significant macular edema, severe non-proliferative or proliferative retinopathy.

Results: During the study period, 62 patients had had myocardial infarction, 54 stroke and 99 patients died. Patients with sight-threatening retinopathy at baseline (n=41) had a 2.2-fold increased (p<0.01) risk for death compared to patients with no or background retinopathy, even when controlled for medical risk factors. When adjusted for medical risk factors, patients with no retinopathy at baseline (n=226) who remained without retinopathy or developed background retinopathy (n=187) during the study period, had a 3.6-fold increased risk for death (95% CI, 1.1, 11.8), (p=0.03), compared to patients who developed sight-threatening retinopathy (n=39), while the incidence of myocardial infarction did not differ. More patients who developed sight-threatening retinopathy were treated with ACE inhibitors than patients who did not (41% versus 24%; p=0.03).

Conclusion: Despite more medical risk factors, patients who developed sight-threatening retinopathy had lower mortality compared to patients with no or background retinopathy at follow-up. More patients who developed sight-threatening retinopathy were treated with ACE inhibitors but this seemed not to have influenced the lower mortality rate in this group, whereas the use of ACE inhibitors in patients who did not develop sight-threatening retinopathy was connected with lower mortality rate.