[Clinical trials on glaucoma: differences according to the medical or surgical nature of the treatment being evaluated]

Abstract

Purpose: To compare the quality of clinical trials on glaucoma between those evaluating the effectiveness of medical treatments and those evaluating surgical treatments.

Method: Clinical trials on glaucoma published in seven international journals between January 1980 and December 1999 were selected. The papers were revised by researchers with a background in epidemiology using a standard qualitative questionnaire. Proportions were compared using Fisher's exact test.

Results: Sample size was pre-estimated in 19% of medical treatment trials and 2% of surgical trials (p=0.005); masking (72% vs. 9%; p<0.001) and intention-to-treat analysis (17 vs. 0 papers; p<0.001) were also more frequent in medical trials. Only 50% of the trials correctly described the patient flow.

Conclusions: Quality in clinical trials on glaucoma medical treatment was higher than in surgical trials regarding sample size pre-estimation, masking and intention-to-treat analysis. However, both medical and surgical trials should improve in these aspects and in the patient flow description