The effect of marine n-3 polyunsaturated fatty acids on cardiac autonomic and hemodynamic function in patients with psoriatic arthritis: a randomised, double-blind, placebo-controlled trial

Randomized, double-blind, placebo-controlled trial in adults with psoriatic arthritis recruited from rheumatology departments in Denmark. For the n-3 PUFA group, 72 participants were randomized, 68 were analyzed in the intention-to-treat set, and 58 were included in the per-protocol analysis. Participants had no known cardiac arrhythmias and were not receiving biological therapy or systemic corticosteroids.

Marine n-3 polyunsaturated fatty acids were given orally at 3 g/day as six capsules daily for 24 weeks. The active supplement contained 50% eicosapentaenoic acid (EPA) and 50% docosahexaenoic acid (DHA), compared with an olive oil placebo taken as six capsules daily.

Marine n-3 PUFA supplementation improved cardiac autonomic tone but did not significantly change blood pressure, central blood pressure, or arterial stiffness. In the n-3 group, RR interval increased from 956.55 to 969.94 ms (difference 13.38, 95% CI -5.06 to 31.83; P=0.06) and heart rate decreased from 63.83 to 63.29 min-1 (difference -0.61, 95% CI -1.92 to 0.70; P=0.12). Peripheral systolic blood pressure fell by 3.67 mmHg, but other hemodynamic measures were not meaningfully changed; pulse wave velocity changed by 0.01 m/s (P=0.82). Mild gastrointestinal adverse effects were reported by 9 participants in the n-3 group and 6 in the control group.

The trial was relatively small and short, with attrition from 72 randomized participants in the active arm to 58 per-protocol analyses. Most outcomes were surrogate cardiovascular measures, and several effects were modest or borderline in statistical significance. Generalizability is limited to selected psoriatic arthritis patients from Danish rheumatology clinics, and mild gastrointestinal intolerance occurred.