• Can Patient-Reported Outcomes Serve as Endpoints in Trials?

    By Lynda Seminara
    Selected By: Stephen D. McLeod, MD

    Journal Highlights

    Ophthalmology, May 2019

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    On behalf of the United Kingdom Glaucoma Treatment Study (UKGTS) investigators, Jones et al. gathered and compared self-reported outcomes for UKGTS participants. In the flagship trial, patients with open-angle glauco­ma (OAG) had been assigned to receive latanoprost or placebo drops, and vi­sual field progression was the outcome of interest. Eligible for the subsequent study were patients from UKGTS with newly diagnosed OAG and self-report­ed outcome measures at both baseline and study completion. Because the average changes in patient-reported outcome measures (PROMs) for health- and vision-related quality of life were found to be similar for the placebo and active-treatment groups, the research­ers surmised that PROMs may not be sensitive enough to function as primary endpoints in clinical trials of early-stage glaucoma.

    The PROM study included 182 patients who received latanoprost and 168 placebo recipients. At baseline and trial exit, participants completed gen­eral health PROMs (European Quality of Life in 5 Dimensions [EQ-5D] and 36-item Short Form [SF-36]) as well as glaucoma-specific PROMs (15-item Glaucoma Quality of Life [GQL-15] and 9-item Glaucoma Activity Limita­tion [GAL-9]). The percentage change between PROM values was calculated for each patient and compared between treatment arms. Also compared were differences between patients whose glaucoma remained stable and those who experienced progression (deter­mined by visual field changes).

    The average percentage change in PROMs was similar for the placebo and latanoprost groups, with no signifi­cant between-group difference for any measure (EQ-5D overall, p = .98; EQ-5D visual analog scale, p = .88; SF-36, p = .94; GQL-15, p = .66; GAL-9, p = .87). As expected, there were signif­icant differences in glaucoma-related PROMs between patients with and without progressing glaucoma (GQL-15, p = .02; GAL-9, p = .02), and the differences in general health PROMs were similar for these subgroups (EQ-5D, p = .62; EQ-5D visual analog scale, p = 0.23; SF-36, p = .65).

    The low sensitivity of PROMs may render these tools inadequate as primary endpoints in trials of early-stage glau­coma. Although sensitivity to clinical meaningfulness is a common criterion for outcomes selection, quality of life is important as well. Even if PROMs cannot capture the disease-modifying effects of treatment, these tools may help to assess other consequences of therapy, such as side effects and dosing convenience. (Also see related commen­tary by Scott Wallace, MD, and Jane Edmond, MD, in the same issue.)

    The original article can be found here.