Prediction of nonspecific side effects in rheumatoid arthritis patients by beliefs about medicines

Abstract

Objective: This study examines the determinants of patients' side effects from arthritis medication. Proposed predictors were patients' beliefs about medications, objective disease activity, treatment regimen, and psychiatric and rheumatoid arthritis symptoms.

Methods: In a longitudinal design, 100 rheumatoid arthritis outpatients were investigated at baseline and again at 6 months after receiving both pharmacologic and psychosocial treatment.

Results: Multivariate analyses showed no influence of disease status, type of treatment, or psychiatric or arthritis symptoms on side effects. Heightened concerns about arthritis medication at baseline predicted side effects at baseline (partial correlation r = 0.37, P < 0.001) and at 6 months (partial correlation r = 0.25, P < 0.001) after controlling for relevant disease- and treatment-related variables. In a cross-lagged panel analysis, prior experience with side effects from arthritis medication was ruled out as a cause of heightened concerns, indicating that negative beliefs genuinely contribute to side effects. A comparison of patients who did and did not start new medications showed no difference in side effects in patients with positive beliefs about medications, but led to significantly more side effects in patients with negative beliefs.

Conclusion: Patients' beliefs about arthritis medications were stable and consistently associated with side effects. Patients with greater concerns about their arthritis medications are at higher risk for developing side effects, especially when starting new drugs. Identifying those patients is important to avoid premature drug discontinuation. Research into cause and preventability of negative attitudes to prescribed medicines is needed.

Figure 1

Cross-lagged panel analyses of patient-reported non-specific side effects (Side Effect Scale) and Concerns about medicines (BMQ Specific Concerns) over the course of the study. Note. The Side Effect Scale was standardized within baseline, and 6-month follow-up measurements, in order to exclude variance due to mean changes in side effect reporting over time; age, intake of steroids and anxiety were partialed out of all included data; BMQ = Beliefs about Medicines Questionnaire; *p<0.05, ** p<0.01.

Figure 2

Side effects at 6 month follow-up as a function of BMQ Specific Concerns and changes in medication regimen. Note. BMQ = Beliefs about Medicines Questionnaire. Scores for the BMQ Specific Concerns Scale are dichotomized with a median split (scores ≥ 17 considered high). Included are n = 87 subjects with follow-up data for the Side Effect Scale.