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

Objective

To explore the influence of acupuncture duration on the effect of acupuncute for patients with knee osteoarthritis (KOA).

Methods

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.

Results

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).

Conclusion

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 that of 4-week acupuncture. Further studies are required to further determine the effect of duration of intervention.