Migraine may increase risk of all types of retinal artery occlusion: Study

Based on theories and pathophysiology of a retinal migraine, precipitating factors for a retinal migraine are same for a migraine, with and without aura. Factors include, but are not limited to, emotional stress, high blood pressure, and hormonal contraceptive pills, as well as exercise, being at a higher altitude, dehydration, smoking, low blood sugar, and hyperthermia. Co-morbidity with lupus, atherosclerosis, and sickle cell disease increase the risk of having a retinal migraine.

Hence, Ahmad Al-Moujahed and colleagues from the Byers Eye Institute, Horngren Family Vitreoretinal Center, Stanford University School of Medicine Department of Ophthalmology, Palo Alto, California conducted this study to determine if migraine is associated with increased risk of retinal artery occlusion (RAO).

The authors carried out a retrospective cohort study on a total of 418,965 patients with migraine and matched controls without migraine. Cox proportional hazard regression models were used to investigate the association between migraine and risk of all RAO, central RAO (CRAO), branch RAO (BRAO), and "other" RAO, which includes transient and partial RAO. The main outcome measures were the occurrence of all RAO, including CRAO, BRAO, and other RAO, following first migraine diagnosis.

The results were-

a. Among the 418,965 patients with migraine, 1,060 (0.25%) were subsequently diagnosed with RAO, whereas only 335 (0.08%) of the patients without migraine were diagnosed with RAO.

b. The hazard ratio (HR) for incident all RAO in patients with migraine compared with those without migraine was 3.48 (95% Confidence Interval (CI): 3.07 - 3.94; P <0.0001].

c. This association was consistent across all types of RAO, including CRAO (HR = 1.62; 95% CI: 1.15 - 2.28; P=0.004) BRAO (HR 2.09; 95% CI 1.60 - 2.72; P <0.001), and other types of RAO (HR 4.61; 95% CI 3.94 - 5.38; P <0.001).

d. Patients with migraine with aura had a higher risk for incident RAO compared with those with migraine without aura (HR = 1.58; 95% CI: 1.40 - 1.79; P <0.001). e. This association was consistent for BRAO (HR = 1.43; 95% CI 1.04 - 1.97; P <0.03) and other types of RAO (HR = 1.67; 95% CI 1.45 - 1.91; P <0.001), but was not statistically significant for CRAO (HR = 1.18; 95% CI 0.75 - 1.87; P = 0.475). f. Significant risk factors for this association included increased age, male sex, acute coronary syndrome, valvular disease, carotid disease, hyperlipidemia, hypertension, retinal vasculitis and/or inflammation, and systemic lupus erythematosus.

Hence, it was concluded that "migraine is associated with increased risk of all types of RAO and migraine with aura is associated with increased risk of RAO compared with migraine without aura."