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Abstract #5774 Published in IGR 2-1
Does that drug work? Pitfalls in studies on the efficacy and safety of glaucoma medications (editorial)
Camras CB; Minckler DAmerican Journal of Ophthalmology 2000; 129: 87-89
An interesting and very useful editorial was written by Camras and Minckler. The authors stress the importance of randomized controlled trials. It is unfortunate that, at the moment, it is only IOP that can be measured as a drug effect. The authors state that there is no evidence to show that any topically applied medication achieves adequate optic nerve tissue levels. Somewhat to my surprise, the authors do not mention the long-term effect on visual function of a drug which is the ultimate goal of treatment. Anyway IOP is what we evaluate. The authors give a major warning of the size of placebo effect and substantiate that. Also, the time of measurement is an important confusing factor. Caution is indicated before conclusions are made about relative durations of action of different formulations of a medication, unless utilizing an appropriate study design. It would be ideal to compare the effect in one eye with that of the untreated eye when the drug does not have an effect on the contralateral effect, which is pretty rare. Differences in study group characteristics, as known to all of us, may account for major differences in apparent drug. Therefore, it is often difficult to compare effects in patients, and particularly side-effects of medications in different studies. Occurrence of side-effects may depend on study design and the duration of the study. Even large multicenter trials cannot possibly reveal all potential side-effects of a medication because enrolled subjects never represent the full spectrum of patients treated for glaucoma. Finally, whenever a study comparing medications demonstrates equivalent efficacy without a statistically significant difference, its power to discern a difference between study groups should be reported and considered. To improve the quality of publications, some vision journals now require authors to submit manuscripts conforming to a consolidated standard of reporting trials (CONSORT).
Classification:
11.1 General management, indication (Part of: 11 Medical treatment)
