Abstract
Objectives The Dietary Interventions in Psoriatic Arthritis (DIPSA) study is a multicenter randomized controlled trial (RCT) designed to evaluate the efficacy of 2 personalized dietary interventions in improving clinical outcomes in patients with active psoriatic arthritis (PsA), compared to standard of care.
Methods Adults with moderately active PsA (Disease Activity index for PsA (DAPSA) >10), BMI 25-40, and stable therapy were recruited from 3 centers. Participants were randomized to 1 of 3 arms: (1) Mediterranean (Med) diet focused on healthy food composition; (2) Low-calorie Dietary Approaches to Stop Hypertension (DASH-LC) diet targeting weight reduction; or (3) Standard-of-care control arm receiving general, non-personalized dietary advice. Interventions were delivered by registered dietitians through 2 in-person consultations and 7 structured telephone sessions. Clinical evaluations were performed at baseline, 12, and 24 weeks. Patient-reported outcomes were collected from weeks 0 to 24. The primary outcome was change in DAPSA. Secondary outcomes included changes in pain, PROMIS fatigue, Psoriatic Arthritis Impact of Disease (PsAID), tender/swollen joint counts, anthropometric measures, and inflammatory markers. Hierarchical mixed effect regression models were used for the change in responses from baseline and to assess differences between arms.
Results Of 92 randomized patients (Med: n=31, DASH-LC: n=30, Control: n=31), 80 provided complete data on responses. Mean age was 55±13 (70% women) and mean BMI was 33±4.3. All groups experienced modest and statistically significant weight loss by week 12 (Med: −1.36 kg; DASH-LC: −2.47 kg; Control: −1.88 kg) (Figure 1A), with small additional reductions by week 24. No significant differences in weight loss were observed between arms. At week 12, significant reductions in DAPSA were observed in the DASH-LC (−4.93) and control (−4.25) groups; by week 24 all groups showed improvement (Med: −4.87; DASH-LC: −5.42; Control: −6.53) (Figure 1B) with no significant differences between-groups. Minimal Disease Activity (MDA) was achieved at week 12 by 38% in DASH-LC and 29% in Med vs 16% in control (p=0.23 and p=0.06, respectively) (Figure 1C), though week 24 rates were similar across groups. Improvements in pain, fatigue, PsAID, and tender joint counts were observed across all arms. The magnitude of weight loss was significantly associated with improvement in clinical outcomes, including DAPSA, pain, and tender joint count, independent of treatment group (Figure 1D-1E).
Conclusion Both personalized dietary interventions and standard dietary advice led to modest weight loss and improvements in PsA disease activity. The amount of weight lost was positively associated with the reduction in symptoms.
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