Diet and Exercise in Psoriatic Arthritis

The role of dietary and lifestyle interventions in the management of rheumatic disease is poorly understood but of increasing interest to patients. The 2021 European Alliance of Associations for Rheumatology recommendations for lifestyle behaviors to prevent the progression of rheumatic musculoskeletal diseases highlighted the role of diet and lifestyle in health-related outcomes.¹ While the sparse literature has predominantly evaluated the impact of lifestyle interventions in rheumatoid arthritis (RA), there is very little evidence on whether diet and exercise impact disease outcomes in psoriatic arthritis (PsA).

In this cross-sectional, observational study, Katsimbri et al sought to investigate the impact of dietary and exercise habits on severity of PsA, as well as the effect on response to treatment,² specifically evaluating the Mediterranean diet. The Mediterranean diet encompasses high intake of fruits and vegetables, legumes, and fish and is notably high in micronutrients, trace elements, and antioxidants with anti-inflammatory properties. The study comprised adult patients over 18 years of age with PsA (by CASPAR classification criteria) who were treated in a hospital-affiliated rheumatology clinic in Greece from 2017 to 2021. Patients with psoriasis (PsO) seen in a dermatology clinic at the same hospital were used as controls.

To assess dietary habits, the validated questionnaire of Mediterranean diet adherence was used, with patients grouped according to adherence to the Mediterranean diet (low, moderate, or high adherence). Level of exercise was obtained using the Short Last 7 Days Self-Administered Format of the International Physical Activity Questionnaire, with patients stratified into high exercise, moderate exercise, or low exercise. For example, moderate exercise was defined as meeting any of the following criteria: (a) ≥3 days of vigorous-intensity activity ≥20 minutes per day, (b) ≥5 days of moderate-intensity activity and/or walking ≥30 minutes per day, or (c) ≥5 days of any combination of walking, moderate-intensity, or vigorous-intensity activities, achieving a minimum total physical activity of ≥600 MET-minutes per week. Demographic and disease characteristics and disease activity indices were collected at the time of enrollment.

The study included 355 patients (279 with PsA; 76 with PsO) who completed the diet and exercise questionnaires. Median duration of PsA was 2.1 years; almost half of the cohort had at least 2 comorbidities. There were no significant differences in the frequency of diabetes, hypertension, coronary artery disease, dyslipidemia, and depression between groups. There was more frequent use of methotrexate, leflunomide, and TNF inhibitors in the PsA group compared with the PsO cohort.

Both subpopulations had similar dietary and exercise habits, with most (71%) patients showing a low exercise pattern and approximately half (44%) not following a Mediterranean diet. With increasing levels of exercise, there was a reduction in disease activity (as measured by DAPSA and HAQ; skin disease activity was measured by PASI). Subjects with increased exercise uptake also demonstrated reduced tender and swollen joints and had lower erythrocyte sedimentation rates (ESRs). There was no correlation between diet and disease activity observed, but some reduction in ESR and skin activity was seen when moving from a low to medium Mediterranean diet. As expected, a more active exercise program and a higher Mediterranean diet were associated with a lower body mass index (BMI). After adjusting for BMI, there was a maintained correlation of exercise with reduced PsA disease activity, while diet showed correlation only with enthesitis. The use of TNF inhibitors and other medications was similar across the diet and exercise groups.

The study had several limitations, including the cross-sectional, observational design; further testing with randomized, controlled studies and longer follow-up is needed to corroborate the results. The study evaluated 1 academic hospital center in Greece, where one could hypothesize knowledge and adherence to a Mediterranean diet is much better compared with other Western countries like the United States.

This study demonstrated that patients with PsA with increased exercise or higher adherence to a Mediterranean-style diet have improved disease outcomes and reduced disease activity. Our patients often request information on lifestyle changes to assist in effective management of their underlying rheumatic disease and prevent potential comorbidities, but we often do not have robust evidence-based literature to guide recommendations, particularly outside of RA. Given the increased incidence of comorbidities in PsA, particularly obesity, metabolic syndrome, and cardiovascular disease, this study provides novel evidence of the dual benefits of incorporating dietary and lifestyle changes for disease control and to reduce the burden of comorbidities in PsA.

References

1. Gwinnutt JM, Wieczorek M, Balanescu A, et al. 2021 EULAR recommendations regarding lifestyle behaviours and work participation to prevent progression of rheumatic and musculoskeletal diseases. Ann Rheum Dis. 2023;82(1):48-56. doi:10.1136/annrheumdis-2021-222020
2. Katsimbri P, Grivas A, Papadavid E, et al. Mediterranean diet and exercise are associated with better disease control in psoriatic arthritis. Clin Rheumatol. 2024. doi:10.1007/s10067-024-07080-6