Researchers aim for consensus on measuring the impact of visual impairment
New guidelines that outline best practices for measuring the economic burden of visual impairment will make it easier for the policy, science and medical communities to draw conclusions and compare results across studies.
The guidelines arose from a working group convened by the Association for Research in Vision and Ophthalmology (ARVO) and the International Agency for the Prevention of Blindness (IAPB). They were published this month in the ARVO journal Investigative Ophthalmology and Visual Science (The Cost of Visual Impairment: Purpose, Perspectives, and Guidance).
The group, representing participants from around the world and from major vision research organizations, came together to review the methods used in two US studies and one Australian study and to develop a consensus on appropriate methods to employ in future studies on the cost of vision impairment regardless of where they are conducted.
"When estimates of the cost of visual impairment vary over time or across countries," explains Johns Hopkins University researcher Kevin Frick, PhD, the lead author, "policy makers are left to ponder whether one estimate differs from another because of changes in the population, changes in the impact of the disease or changes in the methods. Researchers can help policy makers by removing one of the potential variables — changes in methods."
In September 2007 ARVO and IAPB organized the Vancouver Economic Burden of Vision Loss Group to examine the various methods used to measure visual impairment impact and recommend best practices. The panel of 12 leading vision researchers and health care professionals proposed seven guidelines, summarized as follows:
- A comprehensive list of costs includes monetary expenditures on health care (hospital, outpatient, and other), monetary expenditures on things other than health care, loss of patient productivity, loss of family member productivity, deadweight losses and loss of patient wellbeing.
- In any assessment of either prevalent or incident costs, the authors should identify the specific items included under the major categories in recommendation 1.
- Costs should be presented as separate line items to facilitate comparisons among studies.
- A default position is to use a single discount rate for all calculations in an analysis.
- The assumed value of purchasing a DALY or QALY should be clearly stated and justified.
- It is essential to indicate the perspective of costs included.
- The decision-making context and starting point of the analysis should be clear. A statement of whether and how the analysis will be used as part of other analyses is essential.
Dr. Frick says the next task is ensuring that the guidelines are disseminated within the research community. Hosting a workshop at an industry conference and sharing the recommendations in additional ophthalmology journals would enhance awareness of the guidelines and support efforts to adopt their practice.
"Following consensus-based guidelines will also make it easier for those asking questions about the impact of visual impairment to know that they are receiving high quality estimates," says Dr. Frick. "And those who are involved in the process of making sure only high quality proposals are funded and only high quality manuscripts get published will have an easier task."