[Risk factors associated with non-radiographic bone erosion in patients with gout].

Objective: To analyze the factors associated with non-radiographic bone erosion in gout patients, to improve the understanding of bone erosion in gout, and to promote the early detection of bone erosion.

Methods: A retrospective analysis was conducted on the medical records of gout patients treated at Beijing Jishuitan Hospital from January 2018 to January 2022. Bone erosion was detectable by ultrasound but not detected by X-ray as non-radiographic bone erosion; no bone erosion was detected by both ultrasound and joint X-ray as undetected bone erosion. A case-control study was used, and the two groups were matched 1 ∶ 2 according to age and sex. The differences between the two groups were compared in terms of general information, joint involvement characteristics, laboratory indicators and complications. In the univariate analysis, P < 0.1 was included in the multivariate analysis, and the conditional Logistic regression was used for the multivariate analysis. P < 0.05 was considered to have statistically significant differences.

Results: Among the 41 patients with non-radiographic bone erosion, the top three joints with bone erosion before its occurrence were metatarsophalangeal joint (12 cases), ankle (10 cases), and knee (7 cases). There were 82 patients undetected with bone erosion. There were no significant differences in general information between the two groups (P>0.05), including age, gender, body mass index, and alcohol consumption history. The characteristics of affected joints in the non-radio-graphic bone erosion group were compared with those in the no bone erosion detected, and the former had more affected joints (P=0.02), and a higher proportion of patients with at least 3 attacks of gout per year (P < 0.001). There were no significant differences in serum uric acid, fasting blood glucose, cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, creatinine, homocysteine, white blood cell count, and urine pH between the two groups (P>0.05). The results of multivariate analysis showed that at least 3 flares of gout per year was an independent risk factor for radiologically negative bone erosion in patients with gout, with an OR (95%CI) of 5.139 (1.529-17.271).

Conclusion: At least 3 flares of gout per year predicts the occurrence of radiologically negative bone erosion, and these patients should be given more attention to achieving treatment targets.