Potential implicit bias in attribution of adverse events in randomized controlled trials in cystic fibrosis.

INTRODUCTION: Although work to date in cystic fibrosis (CF) has elucidated frequencies and characteristics of adverse events, the accuracy of attribution of relatedness to study drug by investigators has not been assessed. We aimed to determine whether there was an association of attribution by group allocation in CF clinical trials. METHODS: We conducted a secondary analysis from 4 CF trials of all persons who experienced an AE. Our primary outcome was the odds of an AE related to active study drug and predictor of interest was the treatment allocation. We constructed a multivariable generalized estimating equation model allowing for repeated measures. RESULTS: A total of 785 subjects (47.5% female, mean age 12 years) had 11,974 AEs, of which 430 were serious. AE attribution was greater with receipt of active study drug as compared to placebo but did not reach statistical significance (OR 1.38, 95% CI 0.98-1.82). Significantly associated factors included female sex (OR 0.58, 95% 0.39-0.87), age (OR 1.24, 95% CI 1.06-1.46) and baseline lung function (per 10%, OR 1.16, 95% CI 1.05-1.28). CONCLUSION: In our large study, there was a non-significant but greater odds of AE attribution (a key element of clinical trial reporting) to active study drug based on assigned treatment to study drug or control which suggests that there is a trend in physicians to attribute blinded safety data to the active drug. Interestingly, females were less likely to have AE attribution to study drug and warrants further work in development and validation of monitoring guidelines and processes.

Correction: Genetic data and cognitively defined late-onset Alzheimer's disease subgroups.

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Genetic data and cognitively defined late-onset Alzheimer's disease subgroups.

Categorizing people with late-onset Alzheimer's disease into biologically coherent subgroups is important for personalized medicine. We evaluated data from five studies (total n = 4050, of whom 2431 had genome-wide single-nucleotide polymorphism (SNP) data). We assigned people to cognitively defined subgroups on the basis of relative performance in memory, executive functioning, visuospatial functioning, and language at the time of Alzheimer's disease diagnosis. We compared genotype frequencies for each subgroup to those from cognitively normal elderly controls. We focused on APOE and on SNPs with p < 10-5 and odds ratios more extreme than those previously reported for Alzheimer's disease (<0.77 or >1.30). There was substantial variation across studies in the proportions of people in each subgroup. In each study, higher proportions of people with isolated substantial relative memory impairment had ≥1 APOE ε4 allele than any other subgroup (overall p = 1.5 × 10-27). Across subgroups, there were 33 novel suggestive loci across the genome with p < 10-5 and an extreme OR compared to controls, of which none had statistical evidence of heterogeneity and 30 had ORs in the same direction across all datasets. These data support the biological coherence of cognitively defined subgroups and nominate novel genetic loci.