Simvastatin and Disease Stabilization in Normal Tension Glaucoma: A Cohort Study

Abstract

To investigate whether simvastatin use is associated with visual field (VF) stabilization in patients with normal tension glaucoma (NTG). Prospective cohort study (ClinicalTrials.gov Identifier: NCT00321386). A total of 256 eyes from 256 Chinese subjects with NTG. Patients were followed up at 4-month intervals for 36 months for VF progression per Anderson's criteria. Clinical parameters were checked for association with progression in multivariate analysis. The primary outcome was the association between simvastatin use and VF progression. Thirty-one patients (12.1%) were taking simvastatin (statin+), and 225 patients (87.9%) were not taking simvastatin (statin-). Baseline age, gender, untreated intraocular pressure, VF indices, vertical cup-to-disc ratio, and central corneal thickness (CCT) were comparable between the 2 groups. There were significantly more patients with a history of hypercholesterolemia, systemic hypertension, and ischemic heart disease in the statin+ group. A total of 121 patients (47.3%) showed evidence of VF progression (mean rate of mean deviation loss was -0.30 decibel per year) during the 36 months of follow-up. Simvastatin use was among 8 of 121 patients (6.6%) who progressed compared with 23 of 135 patients (17.0%) who did not progress (P = 0.011). Logistic regression revealed that history of disc hemorrhage (relative risk [RR] 3.26; 95% confidence interval [CI], 1.21-8.76; P = 0.019), history of cerebrovascular accidents (RR 2.28; 95% CI, 1.03-5.06; P = 0.043), and baseline age (per 10 years older; RR 1.38; 95% CI, 1.08-1.76; P = 0.009) were significant risk factors for VF progression, whereas simvastatin use conferred a protective effect (RR 0.36; 95% CI, 0.14-0.91; P = 0.030). Simvastatin use may be associated with VF stabilization in patients with NTG. A larger scale randomized controlled trial and cost-effectiveness analyses seem warranted.