Abstract
Purpose: :
To evaluate factors that predicted the need for ALT and to characterize post-ALT measures of intraocular pressure (IOP) control in subjects treated initially with medication or surgery for newly-diagnosed open-angle glaucoma in the CIGTS.
Methods: :
ALT was the protocol-required intervention after initial medication or initial surgery failed to adequately control IOP or limit progression of visual field loss. Time from initial treatment to ALT and time from ALT to treatment crossover were analyzed by Kaplan-Meier estimates and Cox regression. SAS 9.1 statistical software (SAS Institute, Cary, NC) was used.
Results: :
Of 307 treated with initial medicine and 292 treated with initial surgery, ALT was conducted after initial treatment in 155 participants (94 medicine, 61 surgery). Time to ALT was significantly shorter in the medicine group (p=0.005); e.g., at five years, the probability of ALT was 29% vs. 19% (medicine vs. surgery, respectively). Time to ALT was also significantly shorter for three other factors: worse baseline mean deviation [hazard ratio (HR) = 0.9, p<0.0001]; lower education (<grade 12 vs. grade 12 or more, HR = 2.0; p<0.0001), and diabetes (HR = 1.5, p=0.029). By five years after ALT, the probability of further treatment (crossover) was 36% for trabeculectomy in the medicine group vs. 51% for medication use in the surgery group (p=0.061, log-rank test).
Conclusions: :
These results identify baseline, pre-treatment factors that were associated with an increased need for ALT after initial treatment with medication or surgery. Some factors, such as worse mean deviation and diabetes, may be signals for more frequent follow-up to monitor IOP control. Lower education may be indicative of underlying health behaviors or economic influences that are amenable to intervention. The need for ALT was more pronounced within those treated with initial medications, whereas among those who failed initial treatment and underwent ALT, failure of ALT and need for further intervention was somewhat greater among those in the surgery group.
Clinical Trial: :
www.clinicaltrials.gov NCT00000149
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • clinical (human) or epidemiologic studies: risk factor assessment • intraocular pressure