Association of Systemic Calcium Channel Blocker Use with Visual Field Progression in a Large Real-World Cohort from Glaucoma Clinics.

PURPOSE

To test the association between use of calcium channel blocker (CCB) medications and the rate of visual field (VF) progression in a large cohort of patients from 5 glaucoma clinics.

DESIGN

Retrospective longitudinal case-control study.

SUBJECTS

Patients attending 5 glaucoma clinics in the United Kingdom using the same electronic medical record (EMR) system.

METHODS

For the main analysis, we selected 1 eye from patients with at least 5 reliable (false positive errors < 15%) VFs over a period of at least 4 years. The use of systemic medications was derived from the EMR system. Calcium channel blocker users were identified as cases. Propensity score matching (PSM) and multivariable analyses (MVAs) were used to adjust for confounders. A directed acyclic graph of the relevant variables guided the selection of covariates. Linear mixed-effect models (LMMs) were used to test the effect on the rate of VF mean deviation (MD) associated with CCB use and other covariates (for the MV analysis). Sensitivity analyses were conducted with different inclusion criteria and cutoffs on the estimated duration of CCB use.

MAIN OUTCOME MEASURES

The mean difference in the rate of VF MD progression between CCB users and controls.

RESULTS

The main analysis included 14 475 eyes (1942 from CCB users) that met the selection criteria (1 eye per patient). The median (interquartile range) VF series length was 8 (6, 11) tests, with a follow-up of 8.6 (6, 11.5) and 8.2 (5.9, 11.2) years in CCB users and controls, respectively. One-to-one PSM pairing with controls was achieved for all CCB users. The estimated rate of MD progression was -0.31 (-0.33 to -0.28) dB/year (mean [95% confidence intervals]) in the CCB users and -0.35 (-0.37 to -0.33) dB/year in the matched controls (P = 0.016). This significant difference was confirmed with the MV analysis including all controls (P = 0.020). All sensitivity analyses confirmed the main results.

CONCLUSIONS

Calcium channel blocker use was statistically significantly associated with a slower rate of VF deterioration after multivariable adjustment. The estimated difference was small and likely not clinically significant but may be influenced by the limited information on the duration of CCB exposure in this cohort. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.