Association of Blood Pressure and Retinal Nerve Fiber Layer Rates of Thinning in Patients with Moderate to Advanced Glaucoma.

Purpose: Investigate the influence of baseline blood pressure (BP) on retinal nerve fiber layer (RNFL) rates of change (RoC) in glaucoma patients with central damage or moderate to severe disease.

Design: Prospective cohort study.

Participants: 110 eyes with ≥4 RNFL optical coherence tomography scans and ≥2 years of follow-up.

Methods: Global RNFL RoC were modeled with a Bayesian hierarchical model with subject- and sector-level random effects. Influence of baseline systolic and diastolic BP measures and their interactions with intraocular pressure (IOP) on global RNFL rates of change was investigated in prognostic models adjusting for relevant baseline demographic and clinical measures.

Main outcomes and measures: Magnitude and direction of coefficients for BP, IOP, and their interaction for prediction of global RNFL RoC. One-sided Bayesian p-values denote posterior probability that a regression coefficient is greater than or less than zero with p <0.025 or >0.975 defining significance.

Results: Average (SD) 24-2 visual field mean deviation (MD) at baseline, follow-up time, and number of OCT scans were -8.8 (6.0) dB, 4.3 (0.5) years, and 8.3 (1.4), respectively. In multivariable analyses, female sex, Hispanic ethnicity (vs. White ethnicity), better baseline 24-2 MD, higher contrast sensitivity at 12 cycles per degree, presence of diabetes, and thicker central corneal predicted faster RNFL thinning. Adjusted for covariates, lower diastolic BP combined with higher IOP predicted faster RNFL rates of change. Parallel multivariable models incorporating systolic BP showed similar effects. Among various BP/IOP combinations, eyes with IOP at the 90^th percentile and diastolic (systolic) BP at 10^th percentile demonstrated the fastest RNFL thinning rates (-0.554 and -0.539 μm/year).

Conclusions: Low BP and higher IOP at baseline predicted faster (worse) RNFL rates of change in glaucoma patients with central damage or moderate to advanced disease. While there may be potential benefits to BP management in glaucoma patients, the therapeutic value of BP manipulation in glaucoma patients is yet to be established given the proven benefits of tight BP control in reducing cardiovascular morbidity and mortality.