ASSOCIATION OF COMPLEMENTARY AND ALTERNATIVE MEDICINE USE WITH KNEE SYMPTOMS AND KNEE STRUCTURAL CHANGES OVER 2.6 YEARS: A POPULATION-BASED COHORT STUDY OF TASMANIAN OLDER ADULTS

Background: There is increasing use of complementary and alternative medicines (CAMs) alone or as an adjuvant therapy to conventional palliative medicines. However, there remains clinical uncertainty about the benefit of CAMs in the management of osteoarthritis in older population. Objectives: To describe the association between CAM use (alone or in combination with conventional analgesics) with knee symptoms and structural changes amongst a representative sample of Tasmanian older adults. Methods: A total of 1,099 participants were selected from the Tasmania Older Adult Cohort Study (TASOAC), an ongoing prospective population-based study. Exposure to CAM and conventional medications was classified into four categories according to the national drug code directory: CAM only, conventional analgesics only, both CAM and conventional analgesics, and neither CAMs nor conventional analgesics. Knee pain was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and a 1.5-T MRI of the right knee was performed at baseline and follow-up (around 2.6 years). Longitudinal associations were assessed using mixed effect linear models. Results: At baseline, participants‘ mean age was 63, 86.5% (n=951) reported any medication use. The prevalence of CAM use was 35.0% and of conventional analgesics was 58.6%. Over follow-up, the analgesic only group had a significant increase in WOMAC pain, function, and stiffness scores compared to those who took neither CAMs nor conventional analgesics. There was a statistically significant femoral cartilage volume loss across all four groups, and no statistical difference was found between participants who takes both CAMs and analgesics group and the reference group, but participant in the CAM only or the analgesics only groups loss statistically significant more femoral cartilage volume than the reference group ( Table 1 ). Table 1. Association of change in clinical knee symptoms and knee structural changes over 2.6 years with different medications groups. Mean change for reference group* Change for each category, coefficient (95% confident intervals) CAMs Both Analgesics Reference group* No. of participants 327 128 257 387 327 WOMAC pain (5-50) -0.95 (-1.42, -0.48) 0.04 (-0.85, 0.93) 0.32 (-0.4, 1.04) 0.78 (0.13, 1.43) Ref WOMAC function (17-170) -3.09 (-4.52, -1.67) 1.02 (-1.7, 3.73) 1.39 (-0.81, 3.59) 2.32 (0.33, 4.31) Ref WOMAC stiffness (2-20) -0.39 (-0.62, -0.17) 0.15 (-0.28, 0.58) 0.35 (0, 0.7) 0.40 (0.09, 0.72) Ref Femoral cartilage volume (mL) -187.98 (-228.79, -147.18) -113.81 (-192.60, -35.03) -1.92 (-65.00, 61.17) -127.19 (-186.31, -68.06) Ref *Reference group=participants taken neither CAMs nor conventional analgesics Conclusion: CAM use alone or in combination with conventional analgesics may associate with slower progression of knee pain. Conclusive evidence on the longitudinal benefits of CAM in the management of osteoarthritis among older adults warrants more studies. REFERENCES: [1] Steel A, McIntyre E, Harnett J, et al . Complementary medicine use in the Australian population: Results of a nationally-representative cross-sectional survey. Sci Rep 2018; 8 :17325. [2] National Center for Health Statistics . Long-term Care Drug Database System: Drugs by NDC Class Code, Drug Code and Name 2007 Available from: https://www.cdc.gov/nchs/data/nnhsd/DrugsbyNDCClass3.pdf [accessed date: 2020 23 December]. The data were fitted using mixed effect linear models, which were constructed by entering baseline medication group, phase, the interaction between medication group and phase, covariates (baseline age, sex, body mass index [BMI], baseline value of outcome), the interaction between the covariates and phase, random intercept, and random slope on phase (time). Disclosure of Interests: None declared Citation: Ann Rheum Dis, volume 80, supplement 1, year 2021, page 365Session: New drugs and therapies (Poster Tours)