Utility values and diabetic retinopathy.

PURPOSE: To ascertain the utility values associated with diabetic retinopathy and varying degrees of visual loss.
METHODS: One hundred consecutive patients with diabetic retinopathy and best-corrected visual acuity decreased to 20/40 or worse in at least one eye occurring primarily as a result of diabetic retinopathy were evaluated in a cross-sectional study. Utility values were ascertained in five groups using both the time trade-off and standard gamble methods: group 1 (best-corrected visual acuity in the better eye of 20/20 to 20/25), group 2 (best-corrected visual acuity in the better eye of 20/30 to 20/50), group 3 (best-corrected visual acuity in the better eye of 20/60 to 20/100), group 4 (best-corrected visual acuity in the better eye of 20/200 to 20/400), and group 5 (best-corrected visual acuity in the better eye of counting fingers to hand motions).
RESULTS: The mean utility value for the diabetic retinopathy group as a whole was 0.77 (SD = 0.21; 95% confidence interval [CI], 0.73 to 0.81) with the time trade-off method and 0.88 (SD = 0.20; 95% CI, 0.84 to 0.92) with the standard gamble method. Employing the time trade-off method correlated with the best-corrected visual acuity in the better eye, the mean utility results were as follows: group 1 = 0.85 (95% CI, 0.75 to 0.95), group 2 = 0.78 (CI, 0.72 to 0.84), group 3 = 0.78 (CI, 0.67 to 0.89), group 4 = 0.64 (CI, 0.53 to 0.75), and group 5 = 0.59 (CI, 0.23 to 0.95). Thus, patients in group 1 (best-corrected visual acuity of 20/20 to 20/25 in the better eye) were willing to trade a mean of 15% of their remaining years of life in return for perfect vision in each eye, whereas those in group 5 (best-corrected visual acuity of counting fingers to hand motions in the better eye) were willing to trade a mean of 41% of their remaining years in return for perfect vision in each eye. There was no significant difference in mean utility values between patients who had decreased visual acuity from diabetic retinopathy for 1 year or less compared with those with decreased acuity for more than 1 year. There was also no significant difference in mean utility values between those with a 12th grade education or less compared with those with more than a 12th grade education.
CONCLUSION: Visual loss occurring secondary to diabetic retinopathy is associated with a substantial decrease in patient utility value (and quality of life). The utility value is directly dependent on the degree of visual loss associated with the disease. The length of time of visual loss and amount of formal education do not appear to affect the utility value.