Lower Diastolic Blood Pressure Linked to Faster GCC Thinning in Glaucoma

Kouros Nouri-Mahdavi, MD

A new study investigating the association of baseline blood pressure measures with rates of change of the macular ganglion cell complex supports the consideration of diastolic blood pressure (DBP) as a therapeutic measure in patients with glaucoma.¹

In 105 eyes with moderate to advanced glaucoma included in the study's final multivariable model, lower baseline DBP was associated with faster rates of ganglion cell complex (GCC) thinning and the association was greater at higher intraocular pressure (IOP) levels.

“Cardiovascular risk assessment and treatment of patients with glaucoma in conjunction with their internist may be indicated to optimize blood pressure in these patients,” investigators wrote.¹

There are few data on the association of baseline blood pressure measurements with longitudinal changes in structure or function in patients with glaucoma. Investigators from the Stein Eye Institute at the University of California, Los Angeles aimed to determine the association of baseline blood pressure measures with longitudinal changes of macular GCC, using their recently developed Bayesian framework. Led by Kouros Nouri-Mahdavi, MD, investigators enrolled patients from the ongoing Advanced Glaucoma Progression Study at UCLA in the current cohort study.

Data collection for the cohort began in June 2012 and analyses are based on the data aggregated in June 2018. Inclusion criteria for the study were diagnosis of open-angle or angle-closure glaucoma and evidence of either central damage on 24-2 visual fields or visual field mean deviation worse than –6 dB. Study eyes underwent clinical examinations and macular optical coherence tomography (OCT) measurements approximately every 6 months.

Baseline characteristics of the 105 participants indicate the mean age was 66.9 years and 67 patients were female, while the 10-2 visual field mean deviation was –8.3 dB with a mean follow-up time was 3.6 years. The demographic makeup of the cohort was 15 African American (14.3%), 23 Asian (21.9%), 12 Hispanic (11.4%), and 55 White (52.4%) individuals based on patient self-report. At baseline, the mean DBP and systolic blood pressure (SBP) were 81.9 mm Hg and 136.2 mm Hg, respectively.

In the multivariable model, the interaction IOP x DBP had a significant association with the rate of GCC thinning; eyes with higher DBP, lower IOP, or both had similar negative slopes. Based on the model, data show female sex, history of taking blood pressure medications, higher IOP, thicker central corneal thickness, shorter axial length, higher contrast sensitivity at 12 cycles per degree, and higher baseline 10-2 visual field mean deviation were associated with faster ganglion cell complex thinning.

The analysis suggests that lower DBP was associated with faster rates of ganglion cell complex thinning at higher IOP.  The eyes of participants with low DBP and high IOP had faster GCC slopes ranging from -0.8 μm/y (IOP, 20 mm Hg; DBP, 60 mm Hg) to −0.4 μm/y (IOP, 15 mm Hg; DBP, 80 mm Hg). At an IOP of 8 mmHg to 16 mmHg, every 10 mmHg decrease in DBP was associated with a slower rate of GCC thinning (0.111 μm/y; faster, –0.130 μm/y).

Based on these findings, investigators suggest the importance of avoiding low DBP for slowing the course of glaucoma progression.

“As a lower DBP, but not SBP, was found to be a factor associated with progressive HCC thinning in our study, avoiding low DBP may be considered as a safe therapeutic approach for slowing the course of glaucoma progression," they wrote.¹

References

1. Mohammadzadeh V, Su E, Mohammadi M, et al. Association of Blood Pressure With Rates of Macular Ganglion Cell Complex Thinning in Patients With Glaucoma. JAMA Ophthalmol. Published online February 09, 2023. doi:10.1001/jamaophthalmol.2022.6092