Elevated Serum Uric Acid Level Indicative of Handgrip Strength in Geriatric Patients

According to a recent study published in Arthritis Research & Therapy, older patients who have higher levels of serum uric acid are more likely to have greater handgrip strength.

Serum uric acid levels could be indicative of different diseases, the study authors noted: “… high levels of [uric acid] have been implicated in gout, cardiovascular mortality, and hypertension, while low levels of [uric acid] have been reported to increase the risk of Alzheimer’s disease and fracture.”

For their study, the researchers gathered data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016. The KNHANES has been conducted for over two decades, but 2016 was the first year to include serum uric acid level. Handgrip strength was used to measure muscle strength.

“Using these data, we aimed to investigate the association of serum [uric acid] level with muscle strength after adjusting for various confounding factors in a large unbiased nationwide population,” stated the researchers.

The study began with 5,624 patients from the KNHANES VII-1 2016 examination and health survey who had handgrip strength data; they then excluded patients with physician-diagnosed rheumatoid arthritis or osteoarthritis, with all-cause physical activity limitation, who did not respond to a physical activity survey, and who had an estimated glomerular filtration rate > 60 mL/min/1.73 m². This left 4,230 patients, of whom 2,231 were female. Serum uric acid levels were stratified into sex-specific tertiles. Patients were also analyzed based on age: young (20–39 years), middle-aged (40–59 years), and elderly ≥ 60 years).

Differences by Sex, Disease, and Serum Uric Acid Levels

The mean serum uric acid levels ± standard deviation in men and women were 5.78 ± 1.29 mg/dL and 4.3 ± 0.92 mg/dL, respectively; the uric acid tertiles categorized by sex were ≤ 5.2 (T1), 5.3–6.2 (T2), and ≥ 6.3 (T3) mg/dL for men and ≤ 3.9 (T1), 4.0–4.6 (T2), and ≥ 4.7 (T3) mg/dL for women. Across age groups, patients in the high uric acid group had higher rates of obesity and metabolic syndrome. Hypertension was more common among young and middle-aged patients with high uric acid levels. Middle-aged and elderly patients with high uric acid levels had significantly lower diabetes mellitus rates. Physical activity, resistance exercise, protein intake, and cardiovascular disease prevalence did not differ according to uric acid level.

The high serum uric acid group had significantly greater handgrip strength than the low uric acid group among the elderly patients.

“When the elderly population was subdivided according to the presence of metabolic syndrome (metS), the impact of [uric acid] remained significant only in individuals with metS. In the aged population, high serum [uric acid] level reduced the risk for low [handgrip strength] (OR, 95% CI = 0.69, 0.48–0.98, p = 0.041) only in male subjects,” the researchers further observed.

“In the current study, we verified that a high serum [uric acid] level is independently associated with increased HGS in the Korean elderly population. The protective effect of [uric acid] was significant in subjects with metS. In subjects aged 20–59 years, the association of [uric acid] with [handgrip strength] was not observed after adjustment for confounding factors,” the study authors wrote, concluding, “[uric acid] seems to enhance muscle strength, especially in elderly individuals with metS.”