Knee osteoarthritis is a common painful condition, affecting 20 million persons in the United States alone. Since there may be safety concerns with typical long-term analgesic therapies — whether acetaminophen, NSAIDs, or opioids — alternative treatments are of great interest. A pair of studies examined the safety and efficacy of turmeric, glucosamine, or mud-pack therapy, with some favorable results.
The rhizome, or root, of turmeric (Curcuma longa linn.) has long been used in traditional Asian medicine to treat gastrointestinal upset, arthritic pain, and other ailments. Some laboratory and animal research has demonstrated anti-inflammatory and antioxidant properties of turmeric and its constituent curcumin. Writing in the journal Inflammopharmacology, researchers at St. John’s Medical College, Bangalore, India report a trial to evaluate this herbal remedy for its safety and efficacy in the treatment of painful knee osteoarthritis (OA), alone or in combination with glucosamine sulphate [Madhu et al. 2012].
This was a 42-day randomized, single-blind, placebo-controlled trial involving 120 patients (37 males, 83 females) with primary knee OA. Subjects were randomized into 4 groups (n=30/group) to receive either (a) placebo (400 mg twice daily), (b) turmeric (500 mg twice daily), (c) glucosamine (750 mg twice daily), or (d) glucosamine + turmeric (at the same doses as groups b and c).
Efficacy was assessed on days 21 and 42, and the primary outcome measures were decreased severity of pain and improved function assessed by Visual Analog Scale (VAS, 100mm) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scale, respectively. Clinical examination of the affected joint used a Clinician Global Impression Change (CGIC) scale.
Posttreatment scores following administration of turmeric using VAS, WOMAC, and CGIC at each clinical visit showed significant improvements (P<0.05) compared with placebo. Also, the turmeric-treated group showed a significant (P<0.01) decrease in the use of rescue medication, along with clinical and subjective improvement compared with placebo.
There were overall improvements in signs and symptoms of OA seen with glucosamine alone and in combination with turmeric, but these reportedly were not statistically significant. The authors noted that turmeric was well-tolerated and safe in all patients throughout the study period, and this should be considered as a useful treatment option for patients with primary painful knee OA.
In a second article, a team of Spanish researchers systematically reviewed all of the scientific studies assessing the effectiveness of mud-pack therapy on patients diagnosed with knee OA [Espejo-Antúnez et al. 2012]. Writing in the journal Rheumatology, they report having identified 115 publications and 20 of those studies were chosen for review based on the inclusion criteria. Those selected were randomized clinical trials, systematic reviews, or meta-analyses whose objective was to analyze the effect of mud-pack therapy on perceived pain, function, and quality of life, with a sample size of ≥20 subjects, published since year 2000, and showing conclusive results.
Of the included studies, 12 analyzed functionality, 17 perceived pain, 5 quality of life, and all showed significant improvements associated with mud-pack therapy for those 3 analyzed variables. The methodological quality of the studies was moderate, with some risk of bias (ie, factors that might skew results). The researchers concluded that mud-pack therapy might be considered as an alternative and effective therapy in the clinical management of knee OA; however, studies with better methodology are needed to prove its scope.
COMMENTARY: The study of turmeric for OA was actually conducted and reported earlier by the lead author, Madhu, as a doctoral dissertation [Madhu 2010, see link below to document]. The turmeric used was designated as NR-INF-02, a water extract of Curcuma longa linn. and Oil of Curcuma longa linn. containing standardized turmerones, which are the chief chemical constituent in the rhizomes.
Turmeric (Curcuma longa) is mainly known as a deep yellow colored herbal powder used in Indian cooking and sometimes has been described as a "super spice" with a long list of health benefits. Therapeutic turmeric extracts and tablets are commercially available, but whether they would have the same constituents and qualities as used in this research study is unknown.
Subjects in all 4 groups in the Madhu study started with moderate pain (mean ≈64mm on VAS) at baseline, and all showed significant improvement by 6 weeks (see Graph). Even the placebo group demonstrated a large 0.87 effect size (Cohen’s d) for pain reduction. However, the largest effect for pain reduction from baseline to day 42 — 71%, or d=2.40 — was with turmeric (ie, NRINFO2) alone. [Note: effect sizes were calculated by us from study data.]
Turmeric also had the largest effect size for pain reduction compared with placebo (d=1.37); however, surprisingly, the addition of glucosamine to turmeric was the least effective therapy for pain compared with placebo (d=0.34). This might be an artifact of relatively small samples sizes and inadequate statistical power, rather than a negative interaction between turmeric and glucosamine.
It also seems unexpected that glucosamine alone would have a relatively strong effect compared with placebo (d=0.81), since other research has not demonstrated this agent as having significant efficacy for OA pain. Whether these results strongly favoring turmeric for knee OA would persist during longer-term therapy and in larger groups is undetermined.
As for the second paper, the use of mud therapy to cure ailments is not common in the U.S.; although, since antiquity, the soil of the earth has been used to remedy all sorts of health problems. Many cultures throughout history have used mud baths to refresh, invigorate, and heal.
Therapeutic mud goes beyond mere common “garden variety” soil, and tends to be brown in color, warm to the touch, and with little or no smell. It is usually composed of a complex, biologically active mixture of both organic and inorganic substances. Therapeutic mud-pack is composed of 3 distinct compounds: clay and mineral salts, liquid from thermal water, and organic matter and bacteria — which may combine to exert beneficial physical, chemical, and thermal effects.
Some research has demonstrated that natural, mineral-rich, mud-pack therapy, applied frequently over a multi-week period, may help to relieve inflammation and slow progression of knee OA. Relief of pain and joint stiffness may be observed over a several month followup period. The treatment appears to be safe; however, long-term effectiveness, ease of accessing such therapy, and cost-benefit relationships need further elaboration.
> Espejo-Antúnez L, Cardero-Durán MA, Garrido-Ardila EM, et al. Clinical effectiveness of mud pack therapy in knee osteoarthritis. Rheumatology. 2012(Dec); online ahead of print [abstract here].
> Madhu K, Chanda K, Saji MJ. Safety and efficacy of Curcuma longa extract in the treatment of painful knee osteoarthritis: a randomized placebo-controlled trial. Inflammopharmacology. 2012(Dec), online ahead of print [abstract here].
> Madhu K. NR-Inf-02, Glucosamine Sulphate, and Combination of the Two in the Treatment of Painful Osteoarthritis: A Randomized, Single Blind, Placebo Controlled Trial [dissertation]. Rajiv Gandhi University of Health Sciences, Karnataka, Bangalore, India; 2010 [PDF document available here].
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