The EQ-5D index often fails to detect the effect of ophthalmic diseases and sight loss. Investigating predictors of individual EQ-5D health dimensions might reveal the underlying reasons. The aim of this study was to investigate predictors of health dimension ratings obtained with the EQ-5D-3L from participants with impaired vision representing a spectrum of eye diseases.
Observational cross-sectional study with participants recruited at four public hospitals in the north of Portugal. Out-patients with visual acuity of 0.30 logMAR (6/12) or worse in the better-seeing eye were invited to take part in the study. Higher values of acuity in logMAR correspond to worse vision. Participants completed two instruments: the EQ-5D-3L and the Massof Activity Inventory (MAI). The MAI provides a measure of visual ability ‒the ability to perform vision-related activities. Higher values of visual ability correspond to greater ease performing activities. The EQ-5D-3L is a generic instrument that frequently is used to quantify the participants’ perceived health-related quality of life. This study used logistic regression models to identify factors associated with self-reported health status estimated from patient responses to the EQ-5D-3L.
The study included 492 participants, mean age 63.4 years (range = 18–93) and 50% females. The most common diagnosis was diabetic retinopathy (37%). The mean visual acuity in the better seeing eye was 0.65 logMAR (SD = 0.48) and the mean visual ability was 0.62 logits (SD = 2.04), correlation between the two was − 0.511 (p < 0.001). Mobility and self-care were the health dimensions with the fewest problems (1% reported extreme problems), anxiety and depression the dimension with the most problems (24% reported extreme problems). Visual ability was an independent predictor of the response for all dimensions, higher ability was always associated with a reduced odds of reporting problems. The odds of reporting problems were increased for females in 3 out of 5 dimensions. Comorbidities, visual acuity and age-category were predictors of the odds of reporting problems for one dimension each.
The odds of reporting problems for the five health dimensions of the EQ-5D-3L are strongly influenced by the ability to perform vision-related activities (visual ability). These findings are informative and relevant for the clinic and for research evaluating the impact of eye diseases and disease treatments in ophthalmology.