Diet Quality and Disease Activity in Rheumatoid Arthritis

Abstract

Background: Rheumatoid arthritis (RA) is a common autoimmune disease that affects the health-related quality of life (HRQOL) of over 1.3 million Americans. RA significantly affects HRQOL through joint deformity, disability, and an increased risk for significant sequela, often regardless of pharmacological therapy. Diet has been considered a factor in exacerbation of RA for decades, and diet quality has been associated with RA risk, associated disability, and disease progression. Unfortunately, research is limited, and findings are unclear. Dietary recommendations continue to be excluded from clinical practice guidelines in RA treatment, and communication is often lacking between providers and patients. Up to 25% of those diagnosed with RA believe their dietary intake affects disease activity and many people change their diet in an attempt to improve their HRQOL. Purpose: The purpose of this study is to examine the association between diet quality and disease activity in adults with RA. Methods: This cross-sectional, descriptive study examined the association between diet quality and disease activity of 50 adults diagnosed with RA. Participants completed the Arizona Food Frequency Questionnaire to measure dietary intake, which was scored with the Healthy Eating Index (HEI)-2015 to determine diet quality. Disease activity was measured via the self-reported Health Assessment Questionnaire-Disability Index and Pain Scale(HAQ-DI and pain scale), hematology analyses for erythrocyte sedimentation rate (ESR) and high-sensitivity C-reactive protein (hs-CRP), and a Disease Activity Score Including 28 Joints (DAS28). The DAS28 was calculated by examining 28 joints, participant self-report, and, in this study, ESR results. Perceived stress was measured with the Perceived Stress Scale. Results: Higher diet quality was not associated with any measures of disease activity (HAQ-DI, pain, DAS28, ESR, or CRP). The mean diet quality score was 56 (SD ± 12), which is lower than the national mean of 59. Higher quality diets were more common in older individuals (p=.015) and women (p=.003). In total, 44% (n=22) participants reported they believe diet affects RA disease activity, and those who believe their diet affects RA were significantly more likely to report dietary changes (p<.0001). Participants with higher educational level (some college or more) were more likely to report the belief that diet affects disease activity (B=-1.535, p=.023). Women with lower diet quality were more likely to have higher HAQ-DI scores (B=.570, p=.001). An increased BMI was associated with decreased DAS28 scores in those with a poor-quality diet (p = .018), but with lower diet quality in those with fair-good diet quality (p =.023). A decreased BMI was significantly correlated with current tobacco use in adults with fair/good quality diet (p= .013). Perceived stress was significantly associated with HAQ-DI and pain scores (B= .445, p=.001 and B= .289, p=.042, respectively). Conclusion: Many individuals with RA should improve their diet as poor diet quality was associated with increased pain and may be related to inflammation. Keywords: Rheumatoid Arthritis, Diet Quality, Disease Activity, Biopsychosocial, Psychoneuroimmunology.