Sixty-five patients with mild to moderate nonproliferative diabetic retinopathy who enrolled in a prospective controlled clinical trial had stereofundus photographs assessed for change over an 8-mo period. The entire study group showed a worsening of retinopathy with time (P < 0.001). The worsening was greater in the pump-treated group (15/32) than in the conventionally treated group (9/33). The significance of this difference ranged from P = 0.67, if changes in mean retinopathy level for each patient were compared, to P = 0.177 if a grading system keyed to the worse eye was compared. The difference in rates of change between treatment groups was found to be related to the baseline mean retinopathy level (P = 0.031), but less significantly so if baseline retinopathy keyed to the worse eye was used as a covariate (P = 0.08). Worsening occurred more frequently in those patients starting with the lower retinopathy levels.
Progression was associated with the appearance of retinal infarcts (cotton-wool spots, soft exudates) and/or intraretinal microvascular abnormalities, with the pump patients showing a significant increase in these individual retinal lesions compared with the conventionally treated patients over 8 mo (P < 0.025).