Objective

Both obesity and synovitis are independently associated with knee osteoarthritis (KOA) progression. We examined whether synovitis mediates the relationship between body mass index (BMI) and KOA radiographic progression in the Osteoarthritis Initiative (OAI) cohort.

Design

We conducted a case-control study within the OAI. Cases (n = 315) were right knees with an increase of ≥1 Kellgren-Lawrence from baseline to 48 months of follow-up. Controls (n = 315) were right knees with no KL change. Cases and controls were matched by age, sex, race, and baseline KL. MRI Osteoarthritis Knee Score (MOAKS) at baseline and at 2 years was used for a semi-quantitative scoring (0–3) of effusion-synovitis and Hoffa-synovitis. Conditional logistic regression estimated associations between BMI and synovitis with KOA progression. Mediation analysis was used to assess the mediating effects of synovitis.

Results

The mean age of participants was 61 years, 70.8% were women, and 87% were White. KOA progression was associated with higher BMI (adjusted OR 1.05; 95%CI 1.01–1.09) and effusion-synovitis relative to no effusion-synovitis (adjusted OR 2.2; 95%CI 1.6–3.1). Associations between effusion-synovitis worsening and KOA progression were more pronounced among obese individuals (OR 34.1; 95%CI 4.2–274.8; P = 0.001) compared to normal weight (OR 3.2; 95%CI 0.8–12.8, P=0.096) individuals. Effusion-synovitis at 2 years, but not at baseline, mediated the relationship between BMI and KOA progression over a 4-year period.

Conclusions

We found that effusion-synovitis worsening mediated the association between BMI and KOA progression and was associated with increased risk of KOA progression, particularly among obese individuals.

中文翻译：

---

渗出性滑膜炎恶化介导肥胖个体体重指数与 Kellgren-Lawrence 进展之间的关联：来自骨关节炎倡议的数据

客观的

肥胖和滑膜炎均与膝骨关节炎 (KOA) 进展独立相关。我们检查了滑膜炎是否介导了骨关节炎倡议 (OAI) 队列中体重指数 (BMI) 和 KOA 影像学进展之间的关系。

设计

我们在 OAI 内进行了病例对照研究。病例 ( n  = 315) 是右膝，从基线到 48 个月的随访增加了 ≥ 1 Kellgren-Lawrence。对照组 ( n  = 315) 是没有 KL 变化的右膝。病例和对照按年龄、性别、种族和基线 KL 匹配。基线和 2 年时的 MRI 骨关节炎膝关节评分 (MOAKS) 用于积液滑膜炎和 Hoffa 滑膜炎的半定量评分 (0–3)。条件逻辑回归估计 BMI 和滑膜炎与 KOA 进展之间的关联。中介分析用于评估滑膜炎的中介作用。

结果

参与者的平均年龄为 61 岁，70.8% 为女性，87% 为白人。KOA 进展与更高的 BMI（调整后的 OR 1.05；95%CI 1.01-1.09）和相对于无积液-滑膜炎的积液-滑膜炎相关（调整后的 OR 2.2；95%CI 1.6-3.1）。 与正常体重（OR 3.2 ；95%CI 0.8-12.8， P =0.096）个体相比，肥胖个体（OR 34.1；95%CI 4.2–274.8； P= 0.001）中渗出液-滑膜炎恶化与 KOA 进展之间的关联更为明显. 2 年时的积液-滑膜炎，而不是基线时，介导了 4 年期间 BMI 和 KOA 进展之间的关系。

结论

我们发现积液-滑膜炎恶化介导了 BMI 和 KOA 进展之间的关联，并且与 KOA 进展风险增加相关，尤其是在肥胖个体中。