Lifestyle interventions for chronic gout.

BACKGROUND: Although lifestyle interventions are commonly recommended in the management of patients with chronic gout, the evidence from trial data for their benefits and safety has not been previously examined in a systematic review.

OBJECTIVES: The objective of this systematic review was to evaluate the benefits and safety of lifestyle interventions for the treatment of people with chronic gout.

SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE for studies on 5 April 2013. We also searched the 2010 to 2011 American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) abstracts and performed a handsearch of the reference lists of included articles.

SELECTION CRITERIA: Studies were included if they were randomised or quasi-randomised controlled trials (RCTs or CCTs) which compared lifestyle interventions to another therapy (active or placebo) in patients with chronic gout. Outcomes of interest were changes in gout attack frequency, joint pain, serum urate levels, tophus size, function, quality of life and adverse effects.

DATA COLLECTION AND ANALYSIS: Two review authors independently applied methods recommended by The Cochrane Collaboration for the selection, appraisal, data collection and synthesis of studies. We assessed the quality of the body of evidence for each outcome using the GRADE approach.

MAIN RESULTS: Only one study (120 participants), at moderate risk of bias, was included in the review. Patients were randomised to one of three interventions: either skim milk powder (SMP) enriched with glycomacropeptide (GMP) and G600, non-enriched SMP or lactose powder, over a three-month period. The frequency of acute gout attacks, measured as the number of flares per month, decreased in all three groups over the three-month study period. Low quality evidence indicated that there was no difference between the SMP/GMP/G600 group and combined control groups (SMP and lactose powder) at three months (mean difference (MD) -0.21, 95% confidence interval (CI) -0.76 to 0.34). There were no significant between-group differences in terms of withdrawals due to adverse effects (risk ratio (RR) 1.27, 95% CI 0.53 to 3.03), and serious adverse events resulting in hospitalisation (2/40 SMP/GMP/G600 group versus 3/80 controls; RR 1.33, 95% CI 0.23 to 7.66). Gastrointestinal adverse effects were the most commonly reported. Pain from self reported gout flares, measured on a 10-point Likert scale, improved more in the SMP/GMP/G600 group compared to controls (MD -1.03, 95% CI -1.96 to -0.10), an absolute difference of 10% (absolute risk difference -0.10, 95% CI -0.20 to -0.01). This is unlikely to be of clinical significance. Physical function, tophus regression and serum urate normalisation were not reported in this study.

AUTHORS' CONCLUSIONS: While there is good evidence from observational studies of an association between various lifestyle risk factors and gout development, there is a paucity of high-quality evidence from randomised controlled trials to either support or refute the use of lifestyle modifications for improving outcomes in people with chronic gout.