Pain Experience and Impact on Patients with Rheumatoid Arthritis: Understanding what is Unacceptable vs Acceptable vs Idealized and how this Affects and is Affected by Other Aspects of their Disease

Many patients with rheumatoid arthritis (RA) are living with a level of pain (“current pain”) that exceeds “acceptable” pain levels, so that quality of life and physical function are significantly impacted. We seek to understand: 1) patient, disease, and pain characteristics that influence the levels of current pain, acceptable pain, and discordance between them at an individual and group level; and 2) implications (e.g., effect on quality of life, physical function, productivity) associated with living with more than acceptable levels of pain. This will be an observational, longitudinal, and descriptive study using existing data from the January and July 2017 National Databank for Rheumatic Disease (NDB)/FORWARD questionnaires. In addition, a set of 8 additional questions will be added to characterize individual-level acceptable/unacceptable pain levels in the January 2018 questionnaire. To be included in the study, individuals must be enrolled in the NDB/FORWARD, have a diagnosis of RA, and be at least 18 years old. The primary variables of interest are: 1) pain, assessed by a numeric rating scale of current pain from 0 (no pain) to 100 (extreme pain), 2) health satisfaction, measured by the question, “ How satisfied are you with your health now?”, and 3) pain acceptance, eight questions that characterize individual-level acceptable pain levels with reference to specific activities (e.g., work around the home, ability to participate in social activities, household chores, etc). In the last two questionnaire phases with completed data management (July 2016 and January 2017), 5,969 and 5,578 individuals with RA responded. Retention from phase to phase is historically over 90%, so for the July 2017 and January 2018 questionnaires, we expect responses from a minimum of 5,020 and 4,518 individuals, respectively. For the primary analyses, multiple logistic regression analyses will test differences in pain and pain interference between respondents who are and are not satisfied with their health, controlling for covariates, including age, sex, disease duration, comorbid conditions, and disability. When possible, analyses will be stratified by specific comorbidities and body mass index-defined obesity. For the secondary analyses to estimate minimal clinically important differences in pain, we will use a “within-patient” score change method by calculating the average change for each rating group (e.g., much better now, somewhat better now) by disease.