Measuring Quality of Life in Macular Degeneration

Abstract:

Patient-reported outcomes are increasingly used in research and clinical practice in ophthalmology as in other medical specialties. Measures of health status, psychological well-being, functional status, and visual function are frequently referred to as quality of life (QOL) measures and have been used as such in research into macular degeneration (MD). However, such patient-reported outcomes do not measure QOL, although the constructs may be related to or influence QOL. When inappropriate or insensitive measures are used as QOL measures, the findings can be misleading and may lead to incorrect management of patients. Care is needed in the selection of patient reported outcomes (PROs) for use in research and clinical practice to ensure that they are appropriate for the intended purpose. In addition, PROs should be psychometrically validated, demonstrating qualities including face, content and construct validity, internal consistency and test-retest reliability and responsiveness.

Utility values obtained using methods such as time trade-off and standard gamble are used to calculate quality adjusted life years and are frequently referred to as QOL measures. However, they do not measure QOL and give no impression of the ways in which MD or any other medical condition impacts on QOL. For older people, such as those with MD, the questions are particularly difficult to answer.

PROs have shown that MD has a considerable negative impact on the lives of people with the condition and on their families. The use of PROs is valuable in assessing the impact of clinical and rehabilitative interventions and other services for people with MD. Ideally a complementary combination of PROs would used for evaluation purposes to ensure considerate, individually tailored and effective management of this group of patients.