Yeh Ying-Ting, Liang Chung-Chao, Chang Chia-Ling, Hsu Chung-Y, Li Pei-Chen
Department of Physical Medicine and Rehabilitation Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.
Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
BMC Musculoskelet Disord. 2020 Aug 10;21(1):531. doi: 10.1186/s12891-020-03562-1.
Knee osteoarthritis (OA) is known to be a progressive degenerative disorder; however, recent evidence suggests that inflammatory mediators contribute to cartilage degradation. Studies have reported that N-acetylcysteine (NAC) had a promising effect on the reduction of the synthesis of proinflammatory and structural mediators by synovial cells. Given the lack of relevant clinical trials, we conducted this study to determine the relationship between NAC use and risk of knee OA.
We designed a retrospective cohort study from 2000 to 2013. Patients who received oral NAC over 28 days within 1 year after the first prescription were defined as the case group, whereas those without NAC use were considered as candidates of the control group. We adopted 1:4 propensity-score matching by age, sex, index year, and comorbidities to obtain the control group. The primary outcome was a new diagnosis of knee OA during the follow-up period.
Our study sample comprised 12,928 people who used NAC and 51,715 NAC nonusers. NAC users had a significantly higher incidence of osteoarthritis (adjusted hazard ratio: 1.42, P < .001) than did NAC nonusers. Also, in analyses stratified by age group and sex, all subgroups exhibited a significantly higher incidence of knee osteoarthritis (P < .0001) among NAC users than among NAC nonusers. The use of oral NAC was associated with nearly four-fold increased the risk of knee OA in the young age group.
Long-term use of oral NAC is associated with a higher risk of knee OA.
膝关节骨关节炎（OA）是一种进行性退行性疾病；然而，最近的证据表明炎症介质会导致软骨降解。研究报告称，N-乙酰半胱氨酸（NAC）对减少滑膜细胞促炎和结构介质的合成具有显著作用。鉴于缺乏相关临床试验，我们开展了本研究以确定NAC的使用与膝关节OA风险之间的关系。
我们设计了一项2000年至2013年的回顾性队列研究。首次处方后1年内接受口服NAC超过28天的患者被定义为病例组，而未使用NAC的患者被视为对照组候选对象。我们通过年龄、性别、索引年份和合并症进行1:4倾向评分匹配以获得对照组。主要结局是随访期间新诊断的膝关节OA。
我们的研究样本包括12928名使用NAC的人和51715名未使用NAC的人。NAC使用者的骨关节炎发病率显著高于未使用者（调整后的风险比：1.42，P < .001）。此外，在按年龄组和性别分层的分析中，NAC使用者中膝关节骨关节炎的发病率在所有亚组中均显著高于未使用者（P < .0001）。在年轻年龄组中，口服NAC的使用与膝关节OA风险增加近四倍相关。
长期口服NAC与膝关节OA风险较高相关。
