EQ-5D vision bolt-on in macular degeneration: associations with visual measures and effect on utility differences and cost-effectiveness of stereotactic radiotherapy.

BACKGROUND

The UK STAR trial [Stereotactic Radiotherapy (SRT) for neovascular age-related macular degeneration (nAMD)] compared 16-Gray SRT (n = 274) with double-masked sham SRT (n = 137) in participants with chronic active nAMD. SRT reduced intravitreal anti-vascular endothelial growth factor (VEGF) re-treatments over two years of pro re nata ranibizumab, followed by two years of routine care. However, this resulted in worse best-corrected visual acuity (BCVA) in Years 3 and 4. This paper describes: associations between the EQ-5D vision bolt-on and visual acuity and patient-reported outcome measures; the impact of SRT on utilities with and without vision bolt-on; how the vision bolt-on affects the cost-effectiveness of SRT plus anti-VEGF versus anti-VEGF alone.

METHODS

Using data from the entire STAR trial cohort, we compared mean BCVA, EQ-5D-5L, and Visual Function Questionnaire-25 (VFQ-25) scores across the three levels of the EQ-5D vision bolt-on. We examined the relationship between BCVA and EQ-5D (with/without the bolt-on) and VFQ-25. An economic evaluation estimated the cost-effectiveness of SRT from a UK national health service perspective over two years and over four years. This used prospective data on EQ-5D-5L and eye-related direct healthcare use.

RESULTS

Participants reporting vision problems on the bolt-on had significantly worse BCVA, EQ-5D-5L, and VFQ-25 scores than those who did not. EQ-5D utilities (with and without the bolt-on) increased with BCVA but showed weaker correlations than VFQ-25 composite scores. Quality-adjusted life years (QALYs) did not differ significantly between treatment groups, with or without the bolt-on. The economic evaluation suggested SRT would reduce healthcare costs by £404 (95% CI: -£1282 to £2092) per patient at a four-year time horizon. The probability of SRT plus anti-VEGF being cost-effective at a £20,000 per QALY threshold was 65% at a four-year time horizon. Sensitivity analyses confirmed the robustness of incorporating the vision bolt-on did not alter the cost-effectiveness conclusion.

CONCLUSIONS

Resource use data from the trial and routine follow-up could be used for future economic models. The vision bolt-on captured quality of life differences between participants but may not be sufficiently responsive to visual acuity decline in trials where only one eye is treated.

TRIAL REGISTRATION: ISRCTN12884465, registration date 01/12/2014.