Gout Limits Function of Lower Extremities in Older Adults

Diana Phillips

July 27, 2015

Older adults with gout and hyperuricemia are more likely to have worse lower extremity function than their peers, but their upper body function appears to be similar, a study has shown.

Lower extremity function is especially poor in patients with gout who are older, who have a higher body mass index, who are of black race, and who have a history of stroke, diabetes, and osteoarthritis, Bridget Teevan Burke, MS, MPH, from the Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, and colleagues report in an article published online July 2 in Arthritis Care & Research.

To assess the relationship between physical function and gout and hyperuricemia, the investigators conducted a cross-sectional analysis comprising 5819 individuals from the ongoing, prospective Atherosclerosis Risk in Communities (ARIC) study who had self-reported gout status, hyperuricemia data, and available physical function measurements. The physical function measures include the Short Physical Performance Battery (SPPB), grip strength assessment, and a 4-m walking test.

Of the 5819 participants, 10% reported a history of gout, and 21% had hyperuricemia. The physical function analysis showed that participants with gout performed worse than those without gout on the SPPB. The prevalence odds of a 1-unit increase in their SPPB score were 0.77, and they were 1.18 times more likely to have a poor SPPB score, the authors report.

Although the association between gout and SPPB score was not different between men and women, the association between gout and poor SPPB performance was greater in men, the authors observe.

With respect to walking speed, patients with gout had slower walking speeds and were 1.19 times more likely to have poor walking speed than those without gout, and the association between gout and poor walking speed was greater in men, the authors report.

There was no difference in grip strength by history of gout overall and by sex, according to the analysis.

As with gout, patients with hyperuricemia had worse SPPB scores and walking speeds, but no difference was observed by grip strength, the authors write.

The investigators analyzed the data for predictors of poor physical function. Among older adults with gout, the likelihood of poor SPPB score increased with every 5-year increase in age (prevalence ratio [PR], 1.27; 95% confidence interval [CI], 1.16 - 1.39), as well as for every 5 kg/m2 increase in BMI (PR, 1.10; 95% CI, 1.02 - 1.19). Poor SPPB score was also more alike for subjects who were black (PR, 1.35; 95% CI, 1.09 - 1.66), current smokers (PR, 1.45; 95% CI, 1.04 - 2.04), and those with a history of stroke (PR, 1.47; 95% CI, 1.06 - 2.04), diabetes (PR, 1.54; 95% CI, 1.27 - 1.88), and osteoarthritis (PR, 1.60; 95% CI, 1.25 - 2.03), the authors report, noting that similar factors for poor walking speed were identified.

Sensitivity analyses showed that the association between hyperuricemia and physical function was similar among participants with and without a history of using gout medication, and that disease duration was not associated with physical function performance.

Although the researchers expected that older adults with gout and hyperuricemia were likely to have worse physical function overall, "We were surprised to see that these associations were limited to lower extremity function," according to principal investigator Mara McAdams DeMarco, PhD, assistant professor, Department of Epidemiology, Department of Surgery, Johns Hopkins. "However, this makes sense, given that the most common localizations of affected joints are in the lower extremity. Patients with gout are most likely to be first affected by lower extremity joints."

Although previous research has focused on irreversible joint damage resulting from gout, "our study suggests that prior to the onset of joint damage, those with gout are at risk of poor physical function," Dr DeMarco told Medscape Medical News. "This deficit in lower extremity physical function is associated with increased risk of mortality in older adults."

The findings also have relevance to clinical practice, Dr DeMarco noted. "Physicians can recognize these high-risk subgroups of older adults with gout in their clinical population and potentially counsel the patients on the benefits of exercise to improve lower extremity physical function."

This study was jointly funded by the Arthritis National Research Foundation and the American Federation for Aging Research. The authors have disclosed no relevant financial relationships.

Arthritis Care Res. Published online July 2, 2015. Abstract


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