Planning Clinical Research and Clinical Care

Proudfoot et al describe an approach to planning an efficient clinical trial designed to determine whether 2 groups have different rates of glaucomatous progression, for example, 2 groups with different treatments. They were able to calculate that in principle it may be possible to detect a difference between 2 groups in the rate of change in visual field (mean deviation) if the 2 rates differ by at least 0.32 dB/y and a difference in the change of retinal nerve fiber layer thickness if they differ by at least 0.54 μm/y. From longitudinal data on a group of patients, they calculate that such differences can be detected about 80% of the time (“power”) within 2 years with 150 participants in each group.
Source: JAMA Ophthalmology - Category: Opthalmology Source Type: research