Cross-sectional evaluation of patient-reported outcomes (PROs) in patients with RLBP1 retinitis pigmentosa enrolled in a Natural History Study

Abstract

Purpose : Evaluation of patient reported outcomes (PROs) enables an understanding of the relationship between patient quality of life (QoL) and disease severity as assessed by various functional and structural measures. The National Eye Institute Visual Functioning Questionnaire-25 (VFQ-25) has been associated with visual function outcomes in retinitis pigmentosa (RP) due to mutations in the RLBP1 gene (RLBP1 RP) (Burstedt et al., 2005 and 2010). However, there is a limited understanding of the Low Luminance Questionnaire (LLQ) in RLBP1 RP patients. The VFQ-25 and the LLQ, together with functional and anatomic endpoints, were assessed as part of a prospective Natural History Study in RLBP1 RP patients. Here, we report preliminary cross-sectional results of the PRO evaluations and their relationship to functional endpoints (results of other endpoints from this study are presented in additional abstracts).

Methods : In a non-interventional, two-center, prospective study of 45 RLBP1 RP patients, annual PRO evaluations (VFQ-25 and the LLQ) were added beginning with the Month 24 follow-up visit. Weighted averages of visual function [logMAR visual acuity (VA), contrast sensitivity (CS) and Humphrey visual field mean deviation (MD)] were calculated (wVA, wCS and wMD) for the visits at which the PRO questionnaires were administered. To account for binocular vision, single weighted averages (wVA, wCS and wMD) of individual eye scores were calculated as 0.75 of the value for the eye with better VA and 0.25 of the value for the fellow eye.

Results : Forty-one patients of the 45 patients enrolled in two sites (26 patients in Umeå, Sweden and 15 in St John’s, Canada) completed both questionnaires. The mean (min, max) total scores of VFQ-25 and LLQ were 56.1 (25.1, 100) and 38.5 (8.7, 80.6), respectively. The mean and standard deviation (SD) age, wVA, wCS and wMD were 48.6 (14.8) years, 0.95 (0.82) logMAR, 0.88 (0.59) logCS and -22.2 (10.3) dB, respectively. The table below provides pairwise Spearman’s correlation coefficients.

Conclusions : The VFQ-25 total score in this study was in agreement with prior studies in 49 RLBP1 RP patients (Burstedt et al., 2005). The VFQ-25 was strongly correlated with wVA, wCS and wMD while the LLQ was strongly correlated with wVA and wMD. VFQ-25 and LLQ scores were strongly correlated.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.