Abstract
Purpose :
Development of new therapeutics to prevent disease progression in early and intermediate dry AMD requires novel endpoints that can be employed in clinical studies. The purpose of this prospective longitudinal observational study was to investigate if the change in Low Luminance Questionnaire (LLQ) scores over time can detect progression of early and intermediate stages of AMD (eAMD and iAMD, respectively).
Methods :
As part of the single-center, prospective, longitudinal, observational Duke FEATURE study (Duke study of Functional Endpoints for Age-related Macular Degeneration), 101 subjects (33 eAMD, 47 iAMD, and 21 controls) were administered the LLQ during the baseline visit. 70 (22 eAMD, 31 iAMD, and 17 controls) completed the longitudinal study and received the LLQ instrument at 24 months.
Results :
The composite mean LLQ score at baseline was significantly lower in iAMD (75.5, SD 16.7) compared to eAMD (86.8, SD 12.4) or normal control (90.1, SD 8.0). Similar between group differences were found at the 24 months visit (iAMD 72.8, SD 16.7; eAMD 85.3, SD 13.7; control 89.5, SD 7.0). However, the change in mean composite LLQ score from baseline to 24 months for each comparison was not significant.
By defining early or intermediate AMD subjects with an LLQ composite score less than the control baseline mean -2SD=74.2 as “affected outliers," we identified among subjects with eAMD 5 of 22 (22.7%) as outliers at baseline and at 24 months, while among subjects with iAMD at baseline and at 24 months, 14 of 31 (45.2%) were identified as “affected outliers.”
When pooling the non-outlier participants in eAMD and iAMD groups (n=34), the composite and all subscale scores apart from the emotional distress subscore were significantly lower at 24 months than baseline (P<0.05). In contrast, in the "affected outlier" subset (n=19), there was no significant difference in LLQ composite or subscale scores at 24 months and baseline except for the extreme lighting subscore (p=0.008).
Conclusions :
Our results suggest that the sensitivity of the LLQ to monitor change in function in eAMD and iAMD over time may be limited by a floor effect. LLQ is a useful PRO to detect disease progression in eAMD and iAMD subjects that are not significantly impaired at baseline (composite LLQ score ≥75).
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.