Oral herbal therapies for osteoarthritis

Question

What systematic reviews are there on effects of oral herbal therapies on osteoarthritis?

Identified literature

Table 1. Systematic reviews with low/medium risk of bias

Included studies	Population/Intervention	Outcome and Results
Bartels et al, 2015, [4] Efficacy and safety of ginger in osteoarthritis patients: a meta-analysis of randomized placebo-controlled trials
5 RCTs (593 participants)	Population: Adult patients with osteoarthritis (OA) in any joint Intervention: Oral ginger preparation (consisting only of extracts of ginger species) Control: Placebo	Ginger vs placebo, 3–12 weeks Pain (n=5): SMD –0.30 Disability (n=5): SMD –0.22 (95% CI, –0.39 to –0.04)
Authors’ conclusion: “As a conclusion, ginger may be considered as part of the treatment of OA, where the patient is motivated for trying this nutraceutical. As with other complementary and alternative therapies, further studies from independent researchers would be able to show if the effects suggested by the present data will stand in the future. Also, as in all treatment of patients which may take other medication, known possible interaction between medicine and nutraceuticals must be considered.”
Dai et al, 2021, [6] Effectiveness of Curcuma longa extract versus placebo for the treatment of knee osteoarthritis: A systematic review and meta-analysis of randomized controlled trials
10 RCTs	Population: Patients with diagnosed knee osteoarthritis (n=783) Intervention: Oral administration of Curcuma Longa-extract. Dose: 80–1 080 mg/day. Treatment duration: 6–16 weeks Control: Orally administrated placebo	Curcurmin vs placebo Pain (n=8): MD –2.21 (95% CI, –3.15 to –1.28) Function (n=5): MD –11.93 (95% CI, –16.63 to –7.23) Adverse events (n=7): No statistically significant difference
Authors' conclusion: “Current evidence indicates that, compared with placebo, Curcuma longa extract has more benefit in pain relief and functional improvement in patients with symptomatic knee OA. However, considering the potential heterogeneity in the included RCTs, these results need to be interpreted with caution. More future high-quality RCTs with large sample sizes are necessary to confirm the benefits of Curcuma longa extract on knee OA.”
Hsiao et al, 2021, [7] The efficacy of high- and low-dose curcumin in knee osteoarthritis: A systematic review and meta-analysis
11 RCTs - 5 studies manufacturer-funded - 2 studies unclear funding	Population: Intervention: Orally administered curcuminoid formulations. Dose: 180 mg–1500 mg/day. Treatment duration: 4–16 weeks   Control: Placebo (n=8) or NSAID (n=3)	Curcumin vs placebo or NSAID Pain (n=9): SMD –1.66 (95% CI –2.56 to –0.76) Function (n=6): SMD –1.50 (95% CI –2.69 to –0.31) Adverse events (n=9) No statistically significant difference Curcumin vs placebo Pain (n=7): SMD –2.07 (95% CI –3.29 to –0.86) Curcumin vs NSAID Pain (n=2): SMD –0.33 (95% CI –0.59 to 0.07)
Authors' conclusion: “The results of our meta-analysis suggest that curcuminoids are effective in pain relief in knee OA and that low- and high-dose curcuminoids have similar effects in improving pain and AEs Curcuminoids are also more effective in achieving pain relief than NSAIDs; therefore, using curcuminoids as an adjunctive treatment in knee OA is recommended. However, current evidence is heterogeneous and mostly refers to short-term use. Thus, further high-quality RCTs of different curcuminoid doses with longer follow-up durations are needed.“
Robertson et al, 2020, [8] Pine bark (Pinus spp.) extract for treating chronic disorders
27 RCTs 3 RCTs on osteoarthritis, all manufacturer-sponsored	Population: Patients with chronic disorders (n=1 641), n=294 diagnosed with osteoarthritis Intervention: Pine bark extract containing procyanidin. Treatment duration 12–14 weeks   Control: Placebo	Pine bark extract vs placebo Pain (n=2): 1 of 2 studies found statistically significant decrease in pain Function (n=2): 1 of 2 studies found statistically significant increase in function
Authors’ conclusion: “In adults with osteoarthritis, it is not clear if pine bark supplements improve pain, swelling or stiffness in the knee, or whether it decreases the use of anti‐inflammatory drugs.”
Cameron et al, 2016, [5] Oral herbal therapies for treating osteoarthritis
49 RCTs (33 interventions)	Population: Persons diagnosed with osteoarthritis (n=5980)   Intervention: Orally consumed herbal therapies Control: Placebo or active control. Placebo (n=40), NSAID (n=12), other control (n=5) (n=9 multiple controls)	Results from meta-analysis reported where applicable Boswellia serrata vs placebo 8–12 weeks Pain (n=4): Larger reductions in pain for intervention group (4 studies) Function (n=4): Larger increase in function for intervention group (4 studies) Harpagophytum vs placebo 17–20 weeks Pain (n=2): No difference in improvement in pain (2 studies) Rosa canina vs placebo 12 weeks Pain (n=2): No statistically significant effect on pain (2 studies)   Salix vs placebo 2–6 weeks Pain (n=2): Larger reductions in pain for intervention group (2 studies)   ASU vs placebo 3 months Pain (n=2): SMD –11.90 (95% CI, –23.95 to –0.15) No statistically significant effect 3–12 months Pain (n=4): SMD –8.47 (95% CI, –15.90 to –1.04) Function (n=4): SMD –0.42 (95% CI, –0.73 to –0.11)
Authors’ conclusion: “There is moderate-quality evidence that in people with OA, Boswellia serrata slightly improved pain and function. The evidence was downgraded to moderate as there is a potential for imprecision due to the small number of participants contributing to these outcomes. There is moderate-quality evidence that avocado-soybean unsaponifiables (ASU) probably improced pain and function slightly but may not preserve joint space. Evidence was downgraded due to inconsistency across results, or imprecision. […] We are uncertain whether other oral herbal products improve OA pain or function, or slow progression of joint structure damage because the evidence available is limited to single studies only, or studies providing data that cannot be pooled. Some of these studies are of low to very low quality [.]” “High tolerance of the medicinal plant products was demonstrated in all studies. Caution is warranted in interpreting safety. Although no serious drug-related adverse events occurred in the studies so far, comprehensice safety data are still required for all medicinal plant products except for the mixture Phytodolor.”
ASU = Avocado-Soybean Unsaponifiables; CI = Confidence Interval; MD = Mean difference; NSAID = Non-Steroidal Anti-Inflammatory Drugs; OA = Osteoarthritis; RCT = Randomised Controlled Trial; RoB = Risk of Bias; SMD = Standardised Mean Difference

References

1. Bartels EM, Folmer VN, Bliddal H, Altman RD, Juhl C, Tarp S, et al. Efficacy and safety of ginger in osteoarthritis patients: a meta-analysis of randomized placebo-controlled trials. Osteoarthritis Cartilage. 2015;23(1):13-21. Available from: https://doi.org/10.1016/j.joca.2014.09.024.
2. Dai W, Yan W, Leng X, Chen J, Hu X, Ao Y. Effectiveness of Curcuma longa extract versus placebo for the treatment of knee osteoarthritis: A systematic review and meta-analysis of randomized controlled trials. Phytother Res. 2021;35(11):5921-35. Available from: https://doi.org/10.1002/ptr.7204.
3. Hsiao AF, Lien YC, Tzeng IS, Liu CT, Chou SH, Horng YS. The efficacy of high- and low-dose curcumin in knee osteoarthritis: A systematic review and meta-analysis. Complement Ther Med. 2021;63:102775. Available from: https://doi.org/10.1016/j.ctim.2021.102775.
4. Robertson NU, Schoonees A, Brand A, Visser J. Pine bark (Pinus spp.) extract for treating chronic disorders. Cochrane Database Syst Rev. 2020.
5. Cameron M, Chrubasik S. Oral herbal therapies for treating osteoarthritis. Cochrane Database Syst Rev. 2014(5):CD002947. Available from: https://doi.org/10.1002/14651858.CD002947.pub2.