Background/Purpose: Acutely painful flares represent the typical clinical burden of gout. Effective therapy can reduce serum uric acid (sUA) levels; however, epidemiologic evidence for the relationship between sUA and the risk gout flares is thought to be limited. The objective here was to systematically summarize the evidence of the association between sUA levels and the risk of gout flares.

Methods: A systematic review of the published literature (1946 to present) was conducted in April 2015 in Medline, EMBASE, and Cochrane, using a search strategy including terms for gout, sUA, and flares. Two reviewers screened abstracts and extracted data from eligible articles reporting flares according to sUA level. The number and proportion of patients experiencing flares, or mean (standard deviation [SD] or error [SE]) flares per patient, were tabulated according to sUA category; mean sUA levels were also tabulated by mean gout flares. Studies were classified as retrospective (flares occurred prior to sUA measure) or prospective (flares occurred after sUA measure), and according to the treatment status of the cohort.

Results: Of 866 abstracts, 19 articles presented estimates of flares according to sUA, and 17 presented estimates relevant to these analyses. In the seven studies describing flares according to sUA category, the proportion of the cohort experiencing flares increased in a dose-response fashion with higher sUA levels; as did the mean flares per gout patient (Table 1). The proportion experiencing flares was 1.4- to 2.8-fold higher in the highest sUA categories compared to the lowest. Mean flares also generally increased with higher sUA levels (Table 1). Ten studies also presented data on mean flares according to mean sUA level; these also demonstrated a dose-response relationship. As expected, clinical cohorts tended to show this relationship more clearly than administrative cohorts.  

Conclusion: Our systematic review of published articles on the risk of gout flares suggested a dose-response relationship, where higher sUA levels were associated with more flares. The selection, assessment methods, and timing of outcome measures were variable between studies. As little evidence from prospective studies designed to comprehensively evaluate flares was identified, existing risk measures are likely underestimates. Nevertheless, the existing evidence underscores the need to treat to target as recommended by the recent gout care guidelines.

Table 1: n (%) patients with flares, and mean (SD) flares over time, according to sUA level and the treatment status of the cohort

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/higher-serum-uric-acid-levels-are-associated-with-an-increased-risk-of-flares-a-systematic-review/