Factors Associated With Bone Erosion Identified in Gout

A high percentage of patients with gout have bone erosions, most frequently in the first metatarsophalangeal joint, according to a study published in Arthritis Care & Research. Data also show that the factors most strongly associated with bone erosion in gout are duration of gout, age, synovial hypertrophy, and number of tophi adjacent to the erosion.

For this study, researchers calculated the prevalence and distribution of bone erosion, as detected by ultrasound, in patients with gout (n=980; 92.9% men; mean age, 50.3 years). Ultrasound signs and clinical variables were included in a multivariate logistic regression analysis to identify factors associated with bone erosion in this population.

Out of the total 980 patients with gout, 44.0% (n=431) showed signs of bone erosion, and for 78.4% (n=338) of these patients, the erosion was located in the first metatarsophalangeal joint. Among those with bone erosion, 51.5% percent (n=222) had a single site of bone erosion, 32.0% (n=138) had 2 sites, 6.7% (n=29) had 3 sites, and 9.7% (n=42) had 4 or more. 

The factors most significantly associated with bone erosion were duration of gout, age, synovial hypertrophy, and presence and number of tophi. Compared with patients with gout <1 year, the odds ratios of patients with gout durations of 1 to 5, 5 to 10, and >10 years were 1.174 (P =.469), 1.618 (P =.038), and 1.949 (P =.011), respectively. Compared with patients <40 years old, the risk for bone erosion increased 1.746-fold (P =.006) for patients between 40 and 59 years old, and 2.648-fold (P <.001) for patients older than 60 years. Compared with patients without tophi adjacent to the eroded joint, patients showed a 3.634-fold increased risk with 1 to 2 tophi, a 10.571-fold increased risk with 3 to 4 tophi, and a 15.390-fold increased risk with 5 or more tophi (P <.001), but no significant difference in risk was seen with increases in tophi size (P =.206).

Despite a few study limitations, including a small sample size and the fact that upper limb joints were not evaluated, investigators identified several factors “independently associated with bone erosion, shedding further light on the links between crystal deposition and joint damage in patients with gout. These results suggest that an early diagnosis of gout, controlling the urate level and decreasing local urate crystal deposition may be the most effective way to prevent bone erosion in patients with gout.”

Reference

Wu M, Liu FJ, Jiang LX, et al. The prevalence and factors associated with bone erosion in patients with gout [published online November 26, 2018]. Arthritis Care Res (Hoboken). doi:10.1002/acr.23816