Effect of acupuncture duration in patients with knee osteoarthritis: A secondary analysis of a multi-center randomized controlled trial

探索不同治疗时长对针刺治疗膝骨关节炎疗效的影响.方法 对一项针刺治疗膝骨关节炎的随机对照试验数据进行二次分析.试验在9家中心招募480例患者, 本次分析只纳入毫针组和电针组的数据.两组均每次针刺30 min, 每周3次, 治疗8周, 随访至第26周.结局指标包括数字评分量表 (NRS) 疼痛评分,西安大略和麦克马斯特大学骨关节炎指数量表 (WOMAC) 功能评分和有效应答率.结果 毫针组和电针组第8周的NRS评分和WOMAC功能评分均低于第4周评分 (P<0.05) , 与第26周相比无显著差异 (P>0.05) .第0-4周的NRS评分和WOMAC功能评分变化值均较第4-8周变化值大 (P<0.05) .两组第8周的有效应答率均高于第4周 (P<0.05) , 与第26周相比均无差异 (P>0.05) .毫针组BMI影响NRS评分 (P<0.05) , 不影响WOMAC功能评分 (P>0.05) .BMI对电针组NRS评分和WOMAC功能评分均无影响 (P>0.05) .其他因素也不影响两组的NRS评分或WOMAC功能评分 (P>0.05) .结论 针对膝骨关节炎患者, 8周针刺治疗的疗效优于4周针刺治疗, 但效应的增速随着治疗时长增加而放缓, 目前不确定8周针刺治疗的远期效应是否优于4周针刺治疗.后续应设置平行对照试验, 进一步确定针刺时长对疗效的影响. [关键词] 膝骨关节炎;针刺;治疗时长;远期效应 To explore the influence of acupuncture duration on the effect of acupuncute for patients with knee osteoarthritis (KOA). This secondary analysis was conducted based on the data of a randomized controlled trial about acupuncture on KOA. A total of 480 patients were recruited at nine centers. Only data from the manual acupuncture (MA) group and electroacupuncture (EA) group were included in this secondary analysis. The needles were retained for 30-min each time and treatment was given three times a week for 8 weeks. The follow-up visit lasted until week 26. Outcomes were numerical rating scale (NRS) on pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function and the response rate. The NRS and WOMAC function at week 8 were lower than those at week 4 (P<0.05), and were no significant difference compared with those at week 26 in MA and EA groups (P>0.05). Greater changes were observed in NRS and WOMAC function during 0-4 weeks compared with those during 4-8 weeks (P<0.05) in both groups. The response rate at week 8 was higher than it at week 4 (P<0.05), and was no significant difference compared with it at week 26 (P>0.05) in both groups. Association was found between BMI and changes of NRS (P<0.05), but not between BMI and WOMAC function (P>0.05) in MA group, while no asscoaition was found between BMI and NRS or WOMAC function in EA group (P>0.05). There was no association found between other factors and NRS or WOMAC function in both groups (P>0.05). For KOA patients, 8-week acupuncture was more effective than 4-week acupuncture in relieving pain and improving joint function, but growth rate of the effect slowed down with increasing duration of intervention. It was uncertain whether the long-term effect of 8-week acupuncture was better than 4-week acupuncture. Further studies are required to further determine the effect of duration of intervention.