Nonadherence to Cardiovascular Drugs Predicts Risk for Non-Arthritic Anterior Ischemic Optic Neuropathy: A Large-Scale National Study

<b>Purpose</b>: While patients with cardiovascular comorbidities are at a higher risk for the occurrence of non-arteritic anterior ischemic optic neuropathy (NAION), it is unclear whether adherence to medication results in risk reduction. The purpose of this study was to investigate whether nonadherence to medical therapy for cardiovascular morbidity correlates with a higher risk for NAION when compared to patients with strict adherence. <b>Methods</b>: A retrospective case-control study was conducted among members of Clalit Health Services in Israel from 2001 to 2022. For each of the 757 NAION cases, three controls (totaling 2271 patients) were matched based on birth year and sex, with a propensity score analysis employed to adjust for a range of comorbidities. A patient was deemed nonadherent with medical treatment if their purchased quantity of medication was less than 60% of the prescribed annual dosage. Mixed models were used to evaluate exposure differences, and conditional logistic regression was applied, incorporating adjustments for socioeconomic status and ethnicity, to examine the impact of medication nonadherence on NAION risk. <b>Results</b>: A total of 3028 patients were included in the study; 757 patients with the diagnosis of NAION and 2271 in the matched control group. The average age of NAION patients was 69 ± 9 years and 55% were male. After adjustments for socioeconomic status and ethnicity, nonadherence to calcium channel blockers (CCBs) (odds ratio [OR]: 1.33, 95% confidence interval [CI]: 1.03-1.71) and anti-arrhythmic (OR: 5.67, 95% CI: 1.89-21.2) medications emerged as significant risk factors. Similarly, nonadherence to cardioprotective medications (OR: 1.46, 95% CI: 1.23-1.74) was also identified as a significant risk factor. <b>Conclusions</b>: Nonadherence to treatments for cardiovascular disease, specifically to medications known to improve prognosis, is associated with a higher risk for NAION.