Diabetes Care, Vol 21, Issue 11 2007-2015, Copyright © 1998 by American Diabetes Association
Improved visual function in IDDM patients with unchanged cumulative incidence of sight-threatening diabetic retinopathy
K Rossing, P Jacobsen, P Rossing, E Lauritzen, H Lund-Andersen and HH Parving
Steno Diabetes Center, Gentofte, Denmark.
OBJECTIVE: To evaluate trends in visual acuity and the cumulative incidence
of diabetic retinopathy in a clinic-based observational follow-up study.
RESEARCH DESIGN AND METHODS: All patients visiting Hvidore Hospital in 1984
whose diagnosis of IDDM had been made before 41 years of age and between
1965 and 1979 (n = 356) were followed until 1994 or until their deaths. All
patients were Caucasians and resided in Copenhagen. Patients were divided
into three prevalence cohorts based on time of diabetes onset: group A,
1965-1969 (n = 113); group B, 1970-1974 (n = 130); and group C, 1975-1979
(n = 113). RESULTS: Fifteen years after diabetes onset, the visual acuity
was significantly improved in patients with increasing calendar year of the
disease onset. The median (interquartile range) visual acuity was 1.0
(0.8-1.0), 1.0(0.9-1.0), and 1.0 (1.0-1.0) in groups A, B, and C,
respectively (P < 0.01 overall; P = 0.28 for group A vs. group B; and P
< 0.01 for group A vs. group C) with 60, 66, and 93 having a visual
acuity of 1.0 in groups A, B, and C, respectively. The cumulative incidence
(+/-SEM), expressed as a percentage and calculated according to the
life-table method, of proliferative retinopathy, maculopathy, and
laser-treated retinopathy 15 years after onset of diabetes were,
respectively, 13+/-3, 11+/-3, and 12+/-3 in group A; 16+/-3, 12+/-3, and
21+/-4 in group B; 11+/-3, 5+/-2, and 12+/-3 in group C, respectively (NS).
The development of proliferative retinopathy was associated with the degree
of retinopathy and albuminuria at baseline and the mean HbA1c during
follow-up. CONCLUSIONS: The study revealed an improvement in visual acuity
with increasing calendar year of diabetes onset but an unchanged cumulative
incidence of diabetic retinopathy.