Regular exercise significantly lessened the excess mortality risk associated with elevated serum uric acid, a large Taiwanese study found.
Among individuals whose serum uric acid was above 7 mg/dL, all-cause mortality risk increased by 22% (adjusted HR 1.22, 95% CI 1.15-1.29), and for those who were physically inactive, the excess risk reached 27% (HR 1.27, 95% CI 1.17-1.37), according to Chi Pang Wen, MD, of National Health Research Institutes in Zhunan, Taiwan, and colleagues.
However, for those who were "fully active," that 27% increase was not only eliminated but was decreased by a further 11%, the researchers reported online in Annals of the Rheumatic Diseases.
"The management of asymptomatic hyperuricemia has been baffling clinicians for decades," the researchers observed. While drug therapy often is initiated when patients develop gout or kidney stones, the majority of asymptomatic cases have gone untreated, in part because of concerns about adverse effects of medications.
However, a growing body of evidence has implicated high serum uric acid in increased risk for cardiovascular and all-cause mortality.
Therefore, to explore whether exercise could be of benefit without the potential hazards of pharmacotherapy, the researchers analyzed outcomes from a prospective cohort study that enrolled 467,976 adults between 1996 and 2008.
Participants all filled out a questionnaire detailing demographics, medical history, and lifestyle factors including physical exercise.
Those who exercised at least 150 minutes per week were classified as fully active, and those with at least 90 minutes of exercise weekly were considered as having low activity.
The hazard ratios for all-cause mortality were adjusted for multiple variables, including, age, sex, body mass index, education, blood pressure, glucose level, and kidney and liver function.
During 13 years of follow-up, there were 12,228 deaths recorded in the national database.
A total of 25.6% of the cohort had serum uric acid levels above 7 mg/dL. These tended to be older men, users of tobacco and alcohol, and to be obese and to have high blood pressure and cholesterol. Half were inactive, reporting no leisure-time exercise.
The researchers also considered the effects of exercise on patients with high uric acid and comorbidities and found that "the beneficial effect of physical activity was consistently similar between those with comorbidities and those without comorbidities in high serum uric acid subjects, reflecting its independent effect."
The analysis also revealed that high uric acid alone was associated with shortened mean lifespan -- 1.4 and 3.8 years in men and women, respectively. These numbers rose to 4.3 and 5.7 years for those who also were inactive.
Most of the individuals classified as fully active reported an average of 30 minutes of moderate physical activity 5 days per week.
"While this is a desirable goal to pursue, we found that those who exercised minimally, like 15 minutes a day instead of 30 minutes, in brisk walking instead of jogging, also had reduced nearly all mortality increases from high serum uric acid," Wen and colleagues noted.
They pointed out that in some Asian populations, up to one-third of individuals have levels of uric acid above 7 mg/dL, as do one-quarter of Americans.
"Thus, high serum uric acid associated with increased mortality is a global phenomenon, affecting one-quarter to one-third of the population, and our recommendation to use physical activity to attenuate such a risk has far-reaching implications, in saving lives as well as in improving quality of life," they stated.
Limitations of the study included the self-report of exercise and the use of uric-acid-lowering medications by some participants.
The study was supported by the Taiwan Department of Health Clinical Trial and Research Center of Excellence.
The authors disclosed no financial relationships with industry.
- Reviewed by Zalman S. Agus, MD Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania
Annals of the Rheumatic DiseasesSource Reference: Chen J-H, et al "Attenuating the mortality risk of high serum uric acid: the role of physical activity underused" Ann Rheum Dis 2014; DOI: 10.1136/annrheumdis-2014-205312.