Are cherries now ripe for use as a complementary therapeutic in gout? Appraisal of the state of evidence

Abstract

Commentary on: Zhang Y, Neogi T, Chen C, et al. Cherry consumption and decreased risk of recurrent gout attacks. Arthritis Rheum 2012;64:4004-11. ContextThe prevalence of gout has risen in the USA and many other countries, owing to a 'perfect storm' of factors, including increased prevalence of comorbid conditions, and diet and alcohol consumption megatrends. Resultant increase in clinical complexity of gouty arthritis and hyperuricaemia management is compounded by relatively poor patient adherence compared to many other medical conditions. This is partly because of gaps in patient and physician education. Notwithstanding, there is substantial interest by patients and clinicians in inexpensive and health-promoting non-pharmacological modalities to potentially improve gout management. Cherries and cherry products, buttressed by an initial uncontrolled study, 1 are a popular folk remedy for gout, as evidenced by more than 1 600 000 'hits' (as of January 2013) in an internet search for the topic 'cherry and gout'. Burgeoning commercial aspects of this phenomenon were linked to US Food and Drug Administration (FDA) warnings to cherry product manufacturers about therapeutic claims in advertisements and websites. There is at least some science on cherries pertinent to gout, which includes evidence for antiinflammatory properties of cherry anthocyanins, and moderate serum urate lowering 2 possibly related to xanthine oxidase inhibition, and to ascorbate uricosuric effects. The work reviewed here is the largest clinical study of cherry consumption to combat gout, to date. MethodsThe internet-based case-crossover study by Zhang and colleagues examined associations of putative risk factors with recurrent attacks of acute gout. Gout patients (n=633) were prospectively recruited and then monitored online for 12 months. To do so, the authors designed a website, and recruited individuals from most states of the USA. Gout diagnosis met preliminary American College of Rheumatology (ACR) criteria in 87.5% of individuals, as confirmed by their physicians. Participants recorded multiple details about their acute gout attacks, including medications and exposure to potential hazards or protective factors during the 2-day period prior to the gout attack, or over four prespecified 2-day control periods; patients served as their own controls. One serving of cherries was defined as half a cup (∼10-12 cherries). Risk of recurrent gout flare was estimated via conditional logistic regression, with multivariate analysis. FindingsMultiple findings suggested cherry intake to be associated with decreased risk of gout attacks. Risk reduction was greater in those who consumed two servings/day of cherry fruit compared to those who consumed one serving, with risk found to be further reduced in those consuming three servings/day ((OR) 0.39, 95% CI 0.20 to 0.77). This trend did not continue to be the same for those consuming four or more cherry servings. Cherry extract intake showed an inverse association with gout flare, similar to that with cherry ...