Objective

To assess the real-world effectiveness of vitamin D supplementation in patients with knee osteoarthritis (KOA) by replicating a randomized controlled trial (RCT) design in an observational study.

Method

This study emulated a target trial using data from the Osteoarthritis Initiative (OAI). Eligible participants were ≥45 years, had symptomatic KOA and did not take vitamin D supplements in the past 30 days. A participant can enter the trial more than once. Participants were included in vitamin D group if they took ≥1,000 IU/day for ≥4 days/week in the past 30 days at the first follow-up visit after baseline. The control group did not use vitamin D in the past 30 days. Optimal propensity score matching at 1:1 ratio was performed. The primary outcome was change in knee pain 2 years after baseline measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes included WOMAC physical function and quantitative joint space width (JSW). Standardized mean difference (SMD) was used to compare the findings with previous RCTs.

Results

A total of 236 person-trials in the vitamin D group were pair-matched with a control. Compared to the control group, vitamin D supplementation did not reach significant changes in WOMAC pain (SMD = −0.04, 95%CI [–0.21, 0.13]), physical function and radiographic JSW over 2 years. The SMDs were consistent with the effect sizes reported in previous RCTs.

Conclusion

Target trial emulation in the OAI cohort demonstrated findings close to published RCTs. This supports the future use of target trial emulation in evaluating other systemic therapies for KOA.

中文翻译：

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维生素 D 补充剂对膝骨关节炎的有效性 - 使用骨关节炎倡议队列数据的目标试验仿真研究

客观的

通过在观察性研究中复制随机对照试验 (RCT) 设计，评估补充维生素 D 对膝骨关节炎 (KOA) 患者的真实效果。

方法

本研究使用骨关节炎倡议 (OAI) 的数据模拟了目标试验。符合条件的参与者年龄≥45 岁，有症状的 KOA，并且在过去 30 天内没有服用维生素 D 补充剂。参与者可以多次参加试验。如果参与者在基线后的第一次随访时在过去 30 天内每周服用 ≥ 1,000 IU 且每周服用 ≥ 4 天，则他们被纳入维生素 D 组。对照组在过去 30 天内没有使用维生素 D。以 1:1 的比例进行最佳倾向得分匹配。主要结果是根据西安大略和麦克马斯特大学骨关节炎指数 (WOMAC) 测量的基线后 2 年膝关节疼痛的变化。次要结果包括 WOMAC 身体功能和定量关节间隙宽度 (JSW)。

结果

维生素 D 组共有 236 人试验与对照组配对。与对照组相比，维生素 D 补充剂在 WOMAC 疼痛（SMD = −0.04, 95%CI [–0.21, 0.13]）、身体机能和影像学 JSW 2 年内未达到显着变化。SMD 与之前 RCT 中报告的效应大小一致。

结论

OAI 队列中的目标试验模拟显示了与已发表的随机对照试验接近的发现。这支持未来使用目标试验模拟来评估 KOA 的其他全身疗法。