Patients' perceptions of the value of current vision: assessment of preference values among patients with subfoveal choroidal neovascularization--The Submacular Surgery Trials Vision Preference Value Scale: SST Report No. 6.

OBJECTIVE: To improve understanding and awareness of the impact of subfoveal choroidal neovascularization (CNV) on health-related quality of life, we sought to measure the preference value that patients with subfoveal CNV assigned to their health and vision status. PATIENTS AND METHODS: Patients with subfoveal CNV completed telephone interviews about their quality of life prior to enrollment and random treatment assignment in the Submacular Surgery Trials, a set of multicenter randomized controlled trials evaluating outcomes of submacular surgery compared with observation. The interviewers asked patients to rate their current vision on a scale from 0 (completely blind) to 100 (perfect vision). The interviewers also asked them to rate complete blindness and then perfect vision, assuming their health otherwise was the same as it was at the time of the interview, on a scale from 0 (dead) to 100 (perfect health with perfect vision). Scores were converted to a 0 to 1 preference value scale for health and vision status, where 0 represents death and 1 represents perfect health and vision. RESULTS: Of 1015 participants enrolled in the Submacular Surgery Trials, 996 completed interviews that included the rating questions, and 792 (80%) answered all 3 rating questions in a manner permitting calculation of a single overall preference value for their current health and vision status on a scale from 0 (dead) to 1 (perfect). The mean preference value was 0.64 (median, 0.68; interquartile range, 0.51-0.80). The preference values correlated with age (Pearson correlation coefficient, -0.11; P = .002), patients' self-rated perception of overall health (Spearman correlation coefficient, 0.36; P<.001), and self-reported perception of vision (Spearman correlation coefficient, 0.47; P<.001). The preference values were significantly lower with poorer visual acuity in the better eye and greater evidence of dysfunction on either the Hospital Anxiety and Depression Scale or the Physical or Mental Component Summary scales of the Short Form-36 Health Survey but did not differ significantly by gender or other baseline characteristics such as race, treatment assignment, or size of the CNV lesion. CONCLUSIONS: Vision loss from subfoveal CNV is associated with patient preference values that are as low as or lower than values previously reported for other serious medical conditions such as dialysis-dependent renal failure and AIDS, indicating that both unilateral and bilateral CNV have a profound impact on how patients feel about their overall health-related quality of life.

Is adjustment of National Eye Institute Visual Function Questionnaire scores for general health necessary in randomized trials?

PURPOSE: To assess whether treatment comparison of National Eye Institute Visual Function Questionnaire (NEI-VFQ) scores in a clinical trial is influenced by general health to warrant adjusting for it. DESIGN: Two randomized pilot trials. METHODS: Patients enrolled in two randomized pilot trials of submacular surgery versus observation for choroidal neovascularization had quality of life interviews (NEI-VFQ and the Short Form-36 Health Survey) 24 months after enrollment. Information on comorbidities was collected through chart reviews. Data from 120 patients were analyzed using linear regression methods. RESULTS: Adjustment for comorbidities did not change the magnitude of the treatment effect on NEI-VFQ scores. However, adjustment for Short Form-36 physical and mental component summaries produced changes in the estimated treatment effect when NEI-VFQ scores were compared. CONCLUSIONS: Adjustment of NEI-VFQ scores for general health may be advisable. The Short Form-36 summary scores may be appropriate for this purpose.