Abstract
Abstract: :
Purpose:A meta–analysis of randomized clinical trials (RCTs) on medical treatment of primary open–angle glaucoma (POAG) was performed in order to 1. properly summarize the evidence of published RCTs; 2. quantitatively obtain a precise estimate of the effect of medical therapy on visual field and optic disc changes. Methods:The search for reports of all RCTs published in English was updated to July 2003. Studies were identified by searching through MEDLINE for specific Medical Subject Headings’ key words (i.e., GLAUCOMA, OCULAR HYPERTENSION, CLINICAL TRIALS) and by inspecting the bibliographies of original and review articles on medical treatment of POAG. Eligible for inclusion were articles published in English that referred to RCTs on medical treatment of POAG or ocular hypertension (OH), comparing an active treatment (or more than one) to placebo or no treatment. As we were interested in the effect of medical treatment on progression of POAG, only RCTs assessing outcomes such as visual field or optic disc changes with a follow–up longer than one year were considered. The quality of the trials was assessed by 2 independent evaluators (LR, SM). The statistical combination of the results of the trials, contrasting an active treatment with an untreated control group, was made with reference to three different end points: a. reduction in IOP; b. occurrence of visual field changes; c. occurrence of optic disc changes. Results: The present systematic review summarizes the results of 8 RCTs published between 1989 and 2003, and evaluating more than 2,700 patients. The pooled estimate of results in occurrence of any end–point indicated a highly significant protective treatment effect with a summary OR of 0.49 (95% CI 0.38–0.61). A statistically significant treatment effect was shown in reducing both visual field progression (OR = 0.59; 95% CI 0.45–0.77) and optic disc changes (OR = 0.35; 95% CI 0.23–0.53). Heterogeneity among studies’ results was not statistically significant. Conclusions: A decrease in IOP of – 4.3 mmHg (17.4%) allowed to obtain a highly significant protective effect of treatment for glaucoma progression. Around 13% of treated got worse despite treatment.
Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • drug toxicity/drug effects