A post-trial survey to assess the impact of dissemination of results and unmasking on participants in a 13-year randomised controlled trial on age-related cataract

<p>Abstract</p> <p>Background</p> <p>The Italian-American Clinical Trial of Nutritional Supplements and Age-Related Cataract was designed to assess the impact of a multivitamin-mineral supplement on age-related cataract. Trial results showed evidence of a beneficial effect of the supplement on all types of cataract combined, opposite effects on two of the three types of cataract (beneficial for nuclear opacities and harmful for posterior sub-capsular opacities) and no statistically significant effect on cortical opacities. No treatment recommendations were made. A post-trial survey was conducted on 817 surviving elderly participants to assess their satisfaction, their understanding of treatment assignment to supplement or placebo and the success of masking.</p> <p>Methods</p> <p>Trial results were communicated by letter and the level of satisfaction and of understanding of the results was assessed by a questionnaire. Participants were offered the option of being unmasked: a second questionnaire was administered to this subset to assess their understanding of the randomisation process and the success of masking.</p> <p>Results</p> <p>610 participants (74.7%) responded to the survey:</p> <p>94.6% thought the description of the results was "very clear" or "quite clear", 5.4% "not clear" or "do not know"; 89.8% considered the results "very interesting" or "quite interesting", 10.2% "not interesting" or "do not know"; 60.3% expressed "satisfaction", 17.2% "both satisfaction and concern", 2.6% "concern", 19.9% "indifference" or "do not know".</p> <p>480 participants (78.7%) accepted the offer to be unmasked to their treatment assignment: 395 (82.3%) recalled/understood the possibility of assignment to vitamins or placebo, 85 (17.7%) did not. 68 participants (17.2%) thought they had taken vitamins (79.4% were correct; p = 0.0006), 47 (11.9%) thought they had taken placebo (59.6% were correct; p = 0.46) and 280 (70.9%) declared they did not know.</p> <p>Conclusions</p> <p>The results were made difficult to explain to study participants by the qualitatively different effect of treatment on the two most visually significant types of cataract. Although the study did not lead to a recommendation to use the dietary supplement, the vast majority of participants reported satisfaction after they received the results but almost 20% of the participants expressed some concern. Masking to treatment assignment was successful in the majority of participants.</p

Changes in Lens Opacities on the Age-Related Eye Disease Study Grading Scale Predict Progression to Cataract Surgery and Vision Loss Age-Related Eye Disease Study Report No. 34

PURPOSE:To investigate whether the 2-year change in lens opacity severity on the Age-Related Eye Disease Study (AREDS) lens grading scale predicts progression to cataract surgery or loss of visual acuity by 5 years. DESIGN:Prospective cohort study within a randomized clinical trial of oral supplements. PARTICIPANTS:The AREDS participants whose eyes were phakic at baseline and free of late age-related macular degeneration throughout the study. METHODS:Baseline and annual lens photographs of AREDS participants (n = 3466/4757; 73%) were graded for severity of cataracts using the AREDS system for classifying cataracts from photographs. Clinical examinations conducted semiannually collected data on cataract surgery and visual acuity. Association of the change in lens opacities at 2 years with these outcomes at 5 years was analyzed with adjusted Cox proportional hazard models. MAIN OUTCOME MEASUREMENTS:Progression of lens opacities on stereoscopic lens photographs at 2 years, cataract surgery, and visual acuity loss of 2 lines or more at 5 years. RESULTS:The adjusted hazard ratios (HRs) for association of progression to cataract surgery at 5 years were: nuclear cataract increase of 1.0 unit or more compared with less than 1.0-unit change at 2 years, 2.77 (95% confidence interval [CI], 2.07-3.70; P &lt; 0.001); cortical cataract increase of 5% or more in lens opacity in the central 5 mm of the lens compared with less than 5% increase at 2 years, 1.91 (95% CI, 1.27-2.87; P = 0.002); and posterior subcapsular cataract increase of 5% or more versus less than 5% in the central 5 mm of the lens, 8.25 (95% CI, 5.55-12.29; P &lt; 0.001). Similarly, HRs of vision loss of 2 lines or more at 5 years for this degree of lens changes at 2 years were the following: nuclear, 1.83 (95% CI, 1.49-2.25; P &lt; 0.001); cortical, 1.13 (95% CI, 0.78-1.65; P = 0.519); and posterior subcapsular cataract, 3.05 (95% CI, 1.79-5.19; P &lt; 0.001). CONCLUSIONS:Two-year changes in severity of lens opacities on the AREDS lens grading scale are predictive of long-term clinically relevant outcomes, making them potential surrogate end points in follow-up studies