This summary of a Cochrane review presents what we know from research about the effect of lifestyle modifications in the treatment of people with chronic gout. There was one study included in this review which looked at the benefits and safety of consuming skim milk powder (SMP) enriched with two components of dairy products (glycomacropeptide (GMP) and G600 milk fat extract) compared to standard skim milk or lactose powder in reducing the frequency of gout attacks over a three-month period.
The review shows that, in people with chronic gout:
Compared with standard skim milk or lactose powder, SMP enriched with GMP and G600 may not reduce the frequency of gout attacks, may not improve physical function, but may reduce pain. We do not know if consuming these dairy preparations improves tophus size (tophi are gout crystal deposits commonly found in skin, on the surface of joints or in cartilage) or blood uric acid levels, as these were not reported.
We do not have precise information about side effects and complications. Possible side effects may include nausea or diarrhoea.
What is gout and what are lifestyle interventions?
Gout is a very common form of painful joint inflammation (arthritis) caused by urate crystals forming either within or around joints. The inflammation can lead to pain, redness and swelling of affected joints, making the area difficult to touch or move. Some of the reasons why people get gout include their genetic makeup, being overweight, ingesting certain medications (e.g. diuretics), having impaired kidney function and lifestyle habits such as drinking excessive amounts of alcohol and sugar-sweetened drinks.
Although medications are the mainstay of gout treatment, given the recognised association between certain lifestyle risk factors and gout development, lifestyle changes such as losing weight, stopping smoking, exercising more, drinking more coffee and dairy products, and consuming less sugar-sweetened drinks, alcoholic beverages, meat and seafood are commonly recommended to people with chronic gout.
Best estimate of what happens to people with gout who consume enriched skim milk powder:
People who consumed enriched skim milk powder had 0.21 fewer gout attacks per month at 3 months (or 2.5 fewer gout attacks per year) .
- People who consumed enriched skim milk powder had 0.49 gout attacks per month (or 6 gout attacks per year).
- People who consumed standard skim milk powder or lactose had 0.70 gout attacks per month (or 8 gout attacks per year).
Withdrawals due to adverse events
4 more people out of 100 who consumed enriched skim milk powder discontinued the supplement at 3 months (4% more withdrawals absolute change, from 10% fewer to 18% more).
- 18 out of 100 stopped consuming enriched skim milk powder.
- 14 out of 100 stopped consuming standard skim milk powder or lactose.
Pain (lower score means less pain)
People who consumed enriched skim milk powder rated their pain 1 point lower on a 0 to 10 point pain scale (10% absolute improvement; 20% to 1% improvement) at 3 months.
- People who consumed enriched skim milk powder rated their pain to be 0.67 points on a scale of 0 to 10.
- People who consumed standard skim milk powder or lactose rated their pain to be 1.7 points on a scale of 0 to 10.
Physical function (lower score means better function)
People who consumed enriched skim milk powder rated their function 0.03 better (0.14 better to 0.08 worse) on a 0 to 3 point scale (1% absolute improvement; 5% improvement to 3% worse) at 3 months.
- People who consumed enriched skim milk powder rated their function to be 0.08 points on a scale of 0 to 3.
- People who consumed standard skim milk powder or lactose rated their function to be 0.11 points on a scale of 0 to 3.
Serious adverse events
1 more person out of 100 who consumed enriched skim milk powder reported a serious adverse event.
- 5 out of 100 who consumed enriched skim milk powder had a serious adverse event.
- 4 out of 100 who consumed standard skim milk powder or lactose had a serious adverse event.
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.
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.
The objective of this systematic review was to evaluate the benefits and safety of lifestyle interventions for the treatment of people with chronic gout.
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.
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.
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.
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. There was no significant difference in physical function between SMP/GMP/G600 and the control groups at three-month followup (MD -0.03, 95% CI -0.14 to 0.08). Tophus regression and serum urate normalisation were not reported in this study.