High rates of macular edema in 25-year cumulative results linked to glycemia, blood pressure

Ophthalmology. 2009; 116(3): 497-503.

A 25-year population-based study found a cumulative incidence of macular edema at nearly 30%, with risk factors including higher glycosylated hemoglobin and higher systolic and diastolic blood pressure.

The Wisconsin Epidemiologic Study of Diabetic Retinopathy examined 955 individuals on insulin who lived in southern Wisconsin. All patients in the study had type 1 diabetes diagnosed before 30 years of age. Of those, 891 had baseline examination with at least one to four follow-ups, between 4 to 25 years. Sixty-four patients died before the first follow-up exam.

Patients had stereoscopic color fundus photographs, which were graded based on the modified Airlie House classification and the Early Treatment Diabetic Retinopathy Study retinopathy severity scheme, study authors said.

The study examined the incidence of macular edema and clinically significant macular edema. Clinicians found that, at 25 years cumulatively, the incidence of macular edema was 29% and clinically significant macular edema was 17%.

Clinicians studied univariate and multivariate analyses. For univariate analyses, they found that macular edema was "associated" with factors including male sex, more severe diabetic retinopathy and more pack-years of smoking. For multivariate analyses, macular edema was associated with higher baseline glycosylated hemoglobin (hazard ratio per 1% 1.17; 95% confidence interval [CI], 1.10-1.25; P < .001) and higher systolic blood pressure (hazard ratio per 10 mm Hg 1.15; 95% CI, 1.04-1.26; P = .004).

"These data show that relatively high 25-year cumulative rates of incidence of [macular edema] were related to glycemia and blood pressure," the study authors said.