In patients with juvenile gout, treatment with the xanthine oxidase inhibitor febuxostat is well tolerated and has been shown to effectively decrease uric acid levels and gout attacks, according to a findings from an analysis published in a letter in Annals of the Rheumatic Diseases.
In this study, Zheng and colleagues sought to evaluate the efficacy and safety of febuxostat in patients with juvenile gout. The single-center cohort study was conducted in Guangdong, China.
A total of 111 individuals (107 men) were enrolled in the study. All participants fulfilled the 2015 American College of Rheumatology/ European Alliance of Associations for Rheumatology (ACR/EULAR) criteria for gout.
Although kidney stones and hypertension are known comorbidities of gout among adults, these disorders were not observed in the children included in the study. Patients with juvenile gout vs adults were more likely to provide a family history of gout in a first- or second-degree relative.
The age at onset of gout in all of the participants was 18 years and younger; the mean age of symptom onset was 15.2 years. The youngest study participant was aged 9 years.
Finger joints were the most common site of gout attacks among children, while knee involvement was more prevalent among adult patients. The presence of gout arthritis was difficult to differentiate from other forms of juvenile arthritis. Although the incidence of tophi was similar among children and adult patients (28% vs 24%, respectively), tophi developed more rapidly in those with juvenile gout than in those with adult-onset gout (mean of 1.5 years in children compared with 7.5 years in adults). In children, finger joints were the most common site for tophi development, while the metatarsophalangeal joints were the most common site among adults.
Individuals with juvenile gout had significantly higher serum uric acid levels than adults (mean, 11.9 mg/dL vs 9.0 mg/dL, respectively; P =.032) but significantly less systemic inflammation (mean erythrocyte sedimentation rates, 18 mm/hour in vs 38 mm/hour; P <.0001; mean C-reactive protein levels, 9.5 mg/L vs 25.3 mg/L, respectively; P <.0001).
With no guidelines currently available for the management of juvenile gout, patients with acute gout were treated with nonsteroidal anti-inflammatory drugs and/or colchicine and received counseling on dietary intervention. All participants who had persistent hyperuricemia were offered urate-lowering therapy after the acute gout attack had been controlled.
Febuxostat was being used as the first-line treatment option in the adult patients with gout at the center in Guangdong, China. The authors used a similar approach in this study, with 37 participants receiving febuxostat 40 mg once daily. In these individuals, a significant reduction in serum uric levels was seen after 1 month of febuxostat therapy (median reduction of 3.6 mg/dL). This improvement in uric acid levels was maintained after 3 months. Notably, the frequency of gout arthritis flares decreased significantly following treatment initiation (pretreatment, 176 events in 679 patient-months; posttreatment, 14 events in 493 patient-months; P <.0001).
Overall, 4 patients who received treatment with febuxostat reported an adverse event, with elevated transient transaminase levels seen in 3 patients, which resolved without treatment discontinuation. Rhabdomyolysis was observed in 1 participant within 3 weeks of treatment initiation who recovered completely following treatment withdrawal.
The authors of the letter concluded that juvenile gout is an aggressive joint disease that merits consideration in the differential diagnosis of childhood arthritides. They added,
“Larger controlled studies are needed to better understand the natural history of juvenile gout and the safety and efficacy of various urate-lowering agents in children.”
Zheng S, Lee PY, Huang Y, et al. Clinical characteristics of juvenile gout and treatment response to febuxostat. Ann Rheum Dis. Letter. Published online December 20, 2021. doi:10.1136/annrheumdis-2021-221762