Influence of Surgical History on Efficacy of Glaucoma Medications in Monocular Trials

Abstract

Abstract: : Purpose: To assess the influence of surgical history on the efficacy of topical glaucoma medications as assessed by monocular trials in clinical practice. Methods: Retrospective chart review of all patient visits, 1996-1998, selecting all monocular trials of anti-glaucoma medications. Data abstracted included age, sex, race, diagnosis, prior and current glaucoma medications, prior glaucoma surgery and prior maximum IOP. The IOP reductions were compared for each drug and for similar drug groupings for the following monocular trial sub-groups: no prior surgery, prior ALT, and prior trabeculectomy or tube shunt. IOP reduction was compared across sub-groups by paired t-test and univariate ANOVA. Results: 700 patients were identified, of which 40 were excluded from analysis because of incomplete data, and 38 because the sample size of patients using these medications was inadequate for analysis. The patients were 54% women, 80% white, 16.7% black; average age was 68.9 years. Diagnoses included 74.0% OAG, 8.8% exfoliative glaucoma, 7.9% CACG, 3.5% pigmentary glaucoma. Similar among treatment groups were: average initial IOP 22.7+6.7mmHg and number of prior laser or incisional surgeries 1.4+1.4. Average number of current and previous medications, 1.4+1.0 and 3.1+1.8, was reduced in the beta-blocker treatment group but similar among the others. Average IOP reduction for all patients was 3.34+6.2 mmHg with 49.4% achieving a 15% or greater reduction in IOP. There were no statistically significant differences in efficacy among the medications, although Latanoprost was most efficacious by absolute or percentage IOP reduction. ANOVA showed significant differences among the IOP lowering effect of the drugs based on prior surgical history. In eyes with prior trabeculectomy or tube shunt, Latanoprost was less efficacious than in those without prior surgery,whereas this was not the case for eyes using Brimonidine and Dorzolamide(p=0.001). The nonselective beta-blockers (smaller sample size) did not show a statistically significant difference between these sub-groups. Prior ALT was not shown to affect drug efficacy. Conclusions: In this group of 622 monocular trials, prior trabeculectomy or tube shunt was associated with increased efficacy of Brimonidine or Dorzolamide.This association was not seen with ALT.

Keywords: clinical (human) or epidemiologic studies: nat • intraocular pressure • pharmacology