Blindness in Patients with Giant Cell Arteritis and its Association with Vascular Disease

Background: Visual loss is a recognized complication of giant cell arteritis (GCA); however, its rate of occurrence has not been estimated accurately and risk factors have not been firmly established. Some studies have implicated cardiovascular disease as a risk factor for blindness, but its contribution has been reported inconsistently. The aim of this study was to assess the frequency of blindness in GCA using a large international prospective cohort of patients newly diagnosed with GCA and, in particular, to evaluate the possible role of vascular risk factors. Methods: The analysis was conducted among recruits to the Diagnosis and Classification Criteria in Vasculitis Study (DCVAS). Physicians from 23 countries recorded clinical data from patients referred to their service with vasculitis over a 2 year period. Visual loss was recorded by completion of the Vasculitis Damage Index (VDI) 6 months after diagnosis, which records visual impairment and uniocular and binocular blindness. Logistic regression analysis was used to assess the association of vascular risk factors and blindness. Results: A total of 433 participants with vasculitis from 23 countries were considered to have GCA with >75% diagnostic certainty, of which 404 fulfilled the 1990 ACR criteria for GCA and 235 had positive temporal artery biopsy. Blindness in at least one eye was noted in 7.85% of participants at 6 months. The logistic regression model identified prevalent diagnoses of stroke [cerebrovascular accident (CVA)] and peripheral vascular disease (PVD) as being positively associated with blindness at 6 months [CVA odds ratio (OR) = 4.47 (95% CI 1.30, 15.41); PVD OR = 10.44 (2.94, 37.03)]. Prevalent diabetes was also associated with blindness at 6 months, but with borderline statistical significance [OR 2.48 (95% CI 0.98, 6.25)]. There was no association between baseline laboratory findings (anaemia, ESR, CRP, platelets) and blindness at 6 months. Conclusion: This is the largest study to date of subjects with GCA and provides a robust estimate of the rate of occurrence of blindness. It suggests that blindness remains a major clinical problem and highlights the need for urgent referral and treatment. The association with prior vascular disease indicates a need for greater vigilance in this group.