Latent factors underlying the patient global assessment of disease activity in rheumatoid arthritis (RA) include pain, depression and anxiety, inability to participate, fibromyalgia, advanced age, and degenerative arthritis, a recent study found. Researchers conducted a prospective cross-sectional study of consecutive patients with RA (70 patients with mean age of 61 years, 73% female, and with mean disease duration of 8 years). Data were collected from the most recent rheumatology visit, including patient characteristics, current RA medications, and comorbidities. Participants completed several validated patient-reported outcome measures. They found:

• The means (SD) for the patient and provider global assessments were 44.6 (22.7) and 20.1 (17.7), respectively.
• Factor analysis yielded 8 factors that represented measurements of pain, fatigue, depression or anxiety symptoms, prior diagnosis of depression or anxiety, advanced age and degenerative arthritis, inability to participate, fibromyalgia (clinical diagnosis and Widespread Pain Index), and undetermined.
• Linear regression analysis showed that fibromyalgia explained the greatest proportion of the variance in the patient global assessment, followed by the other factors.