Central Corneal Thickness of Black and Non-Black Patients with Open-Angle Glaucoma or Ocular Hypertension and IOP Response to Travoprost 0.004% Therapy

Abstract

Abstract: : Purpose: To assess the effect of central corneal thickness (CCT) on differences in intraocular pressure (IOP) response to travoprost 0.004% between black (B) and non-black (NB) patients with open-angle glaucoma (OAG) or ocular hypertension (OHT). Methods: Patients with OAG or OHT were enrolled in a 12-month, randomized, double-masked, multicenter, parallel study with 4 treatment groups. CCT measurements were obtained at study entry. The primary outcome measure was mean IOP. Race response to treatment was assessed after adjusting for baseline differences. Results: Overall, 782 patients were analyzed (175 B and 607 NB). Mean CCT was less for B (550±50 µm, mean±s.d.) than NB (566±44 µm) (p<.01). A smaller percentage of B than NB had CCT>600 µm (12% vs. 21%, p=.01). In total, 195 pts (48 B and 147 NB) received travoprost. Baseline CCT in patients who received travoprost was 553±45 µm for B and 567±45 µm for NB (p=.06). Comparing the results for thicker and thinner corneas, mean IOP across the 1-year study at peak travoprost activity was lower for B than NB by 1.4 to 3.1 mmHg (CCT>600 µm) and 1.2 to 1.8 mmHg (CCT≤600 µm). At 1 year, mean IOP for B and NB pts with baseline CCT>600 µm was 15.7±3.1 and 18.3±3.8 mmHg, respectively. For B and NB pts with baseline CCT≤600 µm, the mean IOP at 1 year was 17.0±3.2 and 18.8±3.6 mmHg, respectively. Analysis of variance was used to adjust the comparisons of mean IOP for baseline differences between B and NB relative to age, sex, diagnosis (OAG vs. OHT), iris color, and CCT. Mean IOP after travoprost remained statistically significantly lower for B than NB after adjustment for these factors (p<.01). This finding was confirmed with an analysis of IOP change from baseline (p<.01). Conclusion: The improved response to travoprost 0.004% of black patients relative to non-black patients is not explained by thinner central corneas or other baseline ocular or general patient characteristics.

Keywords: cornea: clinical science • clinical (human) or epidemiologic studies: tre • drug toxicity/drug effects