Lack of effect of tart cherry concentrate dose on serum urate in people with gout

Stamp LK, Chapman P, Frampton C, Duffull SB, Drake J, Zhang Y, Neogi T · Rheumatology (Oxford)

A dose-ranging trial run by two of the authors of the positive case-crossover study, and it found nothing: no effect of dose on serum-urate area under the curve, on urine urate excretion, on urinary anthocyanin, or on flare frequency (p = 0.76). The authors conclude that if cherry concentrate does reduce flares over a longer period, urate lowering is not how.

Population

Adults with gout and serum urate > 0.36 mmol/L, half on allopurinol

Intervention

Tart cherry juice concentrate at 7.5, 15, 22.5 or 30 mL twice daily for 28 days

Comparator

Placebo

Limitations

n=50 across five arms, so roughly ten people per dose, and 28 days. Underpowered for flares by design. Registered ANZCTR 12615000741583.