Risk communication in clinical trials: a cognitive experiment and a survey.

BACKGROUND: A Royal Statistical Society Working Party recently recommended that "Greater use should be made of numerical, as opposed to verbal, descriptions of risk" in first-in-man clinical trials. This echoed the view of many clinicians and psychologists about risk communication. As the clinical trial industry expands rapidly across the globe, it is important to understand risk communication in Asian countries. METHODS: We conducted a cognitive experiment about participation in a hypothetical clinical trial of a pain relief medication and a survey in cancer and arthritis patients in Singapore. In part 1 of the experiment, the patients received information about the risk of side effects in one of three formats (frequency, percentage and verbal descriptor) and in one of two sequences (from least to most severe and from most to least severe), and were asked about their willingness to participate. In part 2, the patients received information about the risk in all three formats, in the same sequence, and were again asked about their willingness to participate. A survey of preference for risk presentation methods and usage of verbal descriptors immediately followed. RESULTS: Willingness to participate and the likelihood of changing one's decision were not affected by the risk presentation methods. Most patients indicated a preference for the frequency format, but patients with primary school or no formal education were indifferent. While the patients used the verbal descriptors "very common", "common" and "very rare" in ways similar to the European Commission's Guidelines, their usage of the descriptors "uncommon" and "rare" was substantially different from the EU's. CONCLUSION: In this sample of Asian cancer and arthritis patients, risk presentation format had no impact on willingness to participate in a clinical trial. However, there is a clear preference for the frequency format. The lay use of verbal descriptors was substantially different from the EU's.

Causes of Childhood Blindness in North Ghana: Results From a School for the Blind in Wa, Upper West Region

Background: Because most developing countries lack sufficient resources and infrastructure to conduct population-based studies on childhood blindness, it can be difficult to obtain epidemiologically reliable data available for planning public health strategies to effectively address the major determinants of childhood blindness. The major etiologies of blindness can differ regionally and intra-regionally. The objective of this retrospective study was to determine (1) the major causes of childhood blindness (BL) and severe visual impairment (SVI) in students who attend Wa Methodist School for the Blind in Upper West Region, North Ghana, and (2) any potential temporal trends in the causes of blindness for this region.

Methods: In this retrospective study, demographic data and clinical information from an eye screening at Wa Methodist School for the Blind were coded according to the World Health Organization/Prevention of Blindness standardized reporting methodology. Causes of BL and SVI were categorized anatomically and etiologically. We determined the major causes of BL/SVI over time using information provided about the age at onset of visual loss for each student.

Results: The major anatomical causes of BL/SVI among the 190 students screened were corneal opacity and phthisis bulbi (n=28, 15%), optic atrophy (n=23, 13%), glaucoma (n=18, 9%), microphthalmos (n=18, 9%), and cataract (n=18, 9%). Within the first year of life, students became blind mainly due to whole globe causes (n=23, 26%), cataract (n=15, 17%), and optic atrophy (n=11, 13%). Those who became blind after age one year had whole globe causes (n=26, 26%), corneal opacity (n=24, 24%), and optic atrophy (n=13, 13%).

Conclusion: At the Wa Methodist School for the Blind, the major anatomical causes of BL/SVI were corneal opacity and phthisis bulbi. About half of all students became blind within the first year of life, and were disproportionately affected by cataract and retinal causes in comparison to the other students who became blind after age one year. While research in blind schools has a number of implicit disadvantages and limitations, considering the temporal trends and other epidemiological factors of blindness may increase the usefulness and/or implications of the data that come from blind school studies in order to improve screening methods for newborns in hospitals and primary care centers, and to help tailor preventative and treatment programs to reduce avoidable childhood blindness in neonates and schoolchildren.