Statistics
anxiety, fatigue, pain, elevated pain, depression
REGRESSION, CHRONIC PAIN
We were first interested in assessing whether there was a difference in the distribution of responses to individual questions with differing anchor text based on randomization group. The distribution of answers to each of the pain questions, by group, were visualized using raincloud plots. We further presented a table reporting the mean (standard deviation) response to the pain questions based on randomization group, the difference in means between the two groups, and the 95% confidence interval around the difference, as well as the Our key analysis concerned the correlation by randomization group between the 5 pain questions related to the anchoring text, the other two pain questions unrelated to the anchoring text (“compared to a typical day” and “compared to other people”) and the correlates of pain: fatigue, depression and anxiety. We tested whether there was an overall difference in correlations between the two groups using a permutation test, and if there was evidence of a difference, we then tested the difference in individual question pairs based on group by using Fisher’s r-to-Z transformation.Finally, we were interested in assessing whether the association between pain score and anchor text differed based on creativity. For each of the five pain questions, we created separate linear regression models with the individual pain score as the outcome, the randomization group and creativity score as the primary predictors and an interaction term between the two predictors.We chose a sample size of 1,000 for practical reasons of feasibility and cost. We prespecified feasibility as being able to obtain an 80% response rate within a reasonable timeframe (target < 3 months). We prespecified that our cohort would constitute a group of chronic pain patients with elevated pain scores if the mean score for “worst pain” was greater than 6 (with similar standard deviation between the two groups). All analyses were conducted using R version 4.1.0 with the raincloudplots (v0.2.0), tidyverse (v1.3.1) and gtsummary (v1.5.0) packages.