The Relationship Between Visual Acuity and Health-Related Quality of Life. Report From the UK VPDT Cohort Study

Abstract

 

Purpose:

 

The relationship between visual acuity and health-related quality of life (HRQoL)/utility has previously been described only in small, cross-sectional samples. The shape of this relationship, and how it changes longitudinally, are essential for modelling cost-effectiveness of interventions for visually disabling conditions such as age-related macular degeneration (MD).

 

Methods:

 

Patients with neovascular MD commencing a first course of photodynamic therapy (PDT) were recruited into a national prospective cohort study. Refraction protocol best corrected visual acuity (BCVA) was measured on ETDRS charts at baseline and 3 monthly. Short-form SF36 questionnaire was used in a sub-sample at baseline and 6 monthly to calculate mental and physical component scores (MCS, PCS) and SF6D utility score.

 

Results:

 

BCVA and SF36 data were available for 1726 patients; 969 had all data for 1 visit, 606 for 2 visits and 152 for 3 or more. Mapping found a positive linear relationship of BCVA against MCS, PCS and SF6D. For each unit increase in BCVA score, mapping predicted an increase in MCS score of 0.1286, PCS of 0.1299 and SF6D of 0.0018234 (p = 0.000 for all). No evidence of a time effect on the relationship between BCVA and SF36 scores was detected.

 

Conclusions:

 

This paper demonstrates for the first time the relationship between distance VA and QOL measures, using longitudinal data from a large cohort of patients with MD. These important results will provide a strong basis for further work modelling the cost-effectiveness of interventions for MD.  

 

Keywords: quality of life • visual acuity • age-related macular degeneration