Longitudinal associations between complementary and alternative medicine use and pain trajectories in knee...

This study aimed to investigate longitudinal changes in knee pain and function according to complementary and alternative medicine (CAM) use, with a particular focus on acupuncture and chiropractic therapy, among patients with knee osteoarthritis (KOA).

We analyzed data from the Osteoarthritis Initiative, a large longitudinal cohort of patients with KOA. CAM use, including acupuncture and chiropractic therapy, was assessed at baseline and at 2, 4, and 8 years. Changes in knee pain and physical function were measured using the numeric rating scale (NRS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Random-effects panel regression models were used to evaluate the longitudinal associations between CAM use and outcome changes.

Among the 3,838 participants included in the final analysis, approximately 10% reported CAM use at each visit. CAM use was significantly associated with reductions in knee pain over time (β = -0.34, p = 0.007). In modality-specific analyses, chiropractic therapy was significantly associated with pain reduction (β = -0.41, p = 0.005), whereas acupuncture showed a non-significant association with pain improvement. CAM use was not significantly associated with changes in the WOMAC scores. The combined use of acupuncture and chiropractic showed a greater, but non-significant, reduction in pain compared with single-modality use.

CAM use, particularly chiropractic therapy, was associated with a small but statistically significant reduction in knee pain in patients with KOA. Given the modest effect size and observational design, these findings warrant further prospective evaluation of chiropractic care as a non-pharmacological option.