An Investigation into the Effects of a Curcumin Extract (Curcugen®) on Osteoarthritis Pain of the Knee: A Randomised, Double-Blind, Placebo-Controlled Study

The efficacy of curcumin in relieving osteoarthritis: A meta-analysis of meta-analyses

Osteoarthritis (OA) is one of the most prevalent degenerative joint diseases. Several meta-analyses have shown that curcumin could improve the function of the knee and alleviate pain in OA, while some meta-analyses demonstrate controversial results. Hence, we assessed curcumin's effects on knee OA in an umbrella meta-analysis. PubMed, Scopus, Embase, and Web of Science databases were employed to find English-language meta-analyses of randomized controlled trials investigating the effect of curcumin supplementation on OA outcomes up to September 2023. The visual analog scale (VAS), Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain, function, and stiffness scales were analyzed. Effect sizes and 95% confidence intervals were utilized to obtain the overall effect size. A random-effects model was applied to perform the meta-analysis. Heterogeneity was determined by I2 statistics and the Cochrane Q-test. The pooled effect of the 11 included meta-analyses showed that curcumin could significantly decrease the VAS score (weighted mean difference [WMD] and standardized mean difference [SMD]), WOMAC-total (SMD and WMD), WOMAC-Function (SMD and WMD), WOMAC-Pain (SMD), and WOMAC-Stiffness scores (SMD) (p ≤ 0.001, ≤0.001, ≤0.001, 0.007, ≤0.001, 0.002, ≤0.001, ≤0.001, respectively). The results strongly support curcuminoid supplementation in relieving pain, improving joint mobility and stiffness, and shortening medication usage of OA patients.

Medical properties, market potential, and microbial production of golden polyketide curcumin for food, biomedical, and cosmetic applications

Curcumin, a potent plant polyketide in turmeric, has gained recognition for its outstanding health benefits, including anti-inflammatory, antioxidant, and anticancer effects. Classical turmeric farming, which is widely used to produce curcumin, is linked to deforestation, soil degradation, excessive water use, and reduced biodiversity. In recent years, the microbial synthesis of curcumin has been achieved and optimized through novel strategies, offering increased safety, improved sustainability, and the potential to revolutionize production. Here, we discuss recent breakthroughs in microbial engineering and fermentation techniques, as well as their capacity to increase the yield, purity, and cost-effectiveness of curcumin production. The utilization of microbial systems not only addresses supply chain limitations but also helps meet the growing demand for curcumin in various industries, including pharmaceuticals, foods, and cosmetics.

Phytochemicals against Osteoarthritis by Inhibiting Apoptosis

Osteoarthritis (OA) is a chronic joint disease that causes pathological changes in articular cartilage, synovial membrane, or subchondral bone. Conventional treatments for OA include surgical and non-surgical methods. Surgical treatment is suitable for patients in the terminal stage of OA. It is often the last choice because of the associated risks and high cost. Medication of OA mainly includes non-steroidal anti-inflammatory drugs, analgesics, hyaluronic acid, and cortico-steroid anti-inflammatory drugs. However, these drugs often have severe side effects and cannot meet the needs of patients. Therefore, safe and clinically appropriate long-term treatments for OA are urgently needed. Apoptosis is programmed cell death, which is a kind of physiologic cell suicide determined by heredity and conserved by evolution. Inhibition of apoptosis-related pathways has been found to prevent and treat a variety of diseases. Excessive apoptosis can destroy cartilage homeostasis and aggravate the pathological process of OA. Therefore, inhibition of apoptosis-related factors or signaling pathways has become an effective means to treat OA. Phytochemicals are active ingredients from plants, and it has been found that phytochemicals can play an important role in the prevention and treatment of OA by inhibiting apoptosis. We summarize preclinical and clinical studies of phytochemicals for the treatment of OA by inhibiting apoptosis. The results show that phytochemicals can treat OA by targeting apoptosis-related pathways. On the basis of improving some phytochemicals with low bioavailability, poor water solubility, and high toxicity by nanotechnology-based drug delivery systems, and at the same time undergoing strict clinical and pharmacological tests, phytochemicals can be used as a potential therapeutic drug for OA and may be applied in clinical settings.

Efficacy and safety of curcumin therapy for knee osteoarthritis: A Bayesian network meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Curcumin, a polyphenolic compound extracted from turmeric (Curcuma longa L.), is widely used in traditional Chinese medicine to treat osteoarthritis and rheumatoid arthritis. Clinical and experimental studies show that curcuminoid formulations have considerable clinical application value in the treatment of knee osteoarthritis (KOA).

AIM OF THE STUDY

To evaluate the efficacy and safety of curcumin, both alone and in combination with other drugs, in KOA treatment through a Bayesian network meta-analysis (NMA).

METHODS

We searched PubMed, Embase and Cochrane Library for randomized controlled trials of curcumin for KOA treatment. The time range of the search was from the establishment of each database to April 26, 2023. The NMAs of outcome indicators were all performed using a random-effects model. NMAs were calculated and graphed in R using MetaInsight and Stata 140 software. Measurement data were represented by the mean difference (MD), while count data were represented by the odds ratio (OR); the 95% confidence interval (CI) of each effect size was also calculated.

RESULTS

This study included 23 studies from 7 countries, including 2175 KOA patients and 6 interventions. The NMA results showed that compared with placebo, curcumin significantly reduced the visual analogue scale pain score (MD = -1.63, 95% CI: -2.91 to -0.45) and total WOMAC score (MD = -18.85, 95% CI: -29.53 to -8.76). Compared with placebo, curcumin (OR = 0.17, 95% CI: 0.08 to 0.36), curcumin + NSAIDs (OR = 0.01, 95% CI: 0.00 to 0.13) and NSAIDs (OR = 0.11, 95% CI: 0.02 to 0.47) reduced the use of rescue medication. Compared with NSAIDs, curcumin (OR = 0.51, 95% CI: 0.25 to 0.94) and curcumin + NSAIDs (OR = 0.23, 95% CI: 0.06 to 0.9) had a reduced incidence of adverse reactions. The surface under the cumulative ranking curve results indicated that curcumin monotherapy, curcumin + chondroprotective agents, and curcumin + NSAIDs have good clinical value in KOA treatment.

CONCLUSIONS

Curcumin, either alone or in combination with other treatments, is considered to have good clinical efficacy and safety in KOA treatment. Drug combinations containing curcumin may have the dual effect of enhancing efficacy and reducing adverse reactions, but this possibility still needs to be confirmed by further clinical and basic research.

Bioactives and their roles in bone metabolism of osteoarthritis: evidence and mechanisms on gut-bone axis

Bioactives significantly modify and maintain human health. Available data suggest that Bioactives might play a beneficial role in chronic inflammatory diseases. Although promised, defining their mechanisms and opting to weigh their benefits and limitations is imperative. Detailed mechanisms by which critical Bioactives, including probiotics and prebiotics such as dietary lipids (DHA, EPA, alpha LA), vitamin D, polysaccharides (fructooligosaccharide), polyphenols (curcumin, resveratrol, and capsaicin) potentially modulate inflammation and bone metabolism is limited. Certain dietary bioactive significantly impact the gut microbiota, immune system, and pain response via the gut-immune-bone axis. This narrative review highlights a recent update on mechanistic evidence that bioactive is demonstrated demonstrated to reduce osteoarthritis pathophysiology.

Measures of sleep are not routinely captured in trials assessing treatment outcomes in knee osteoarthritis - A scoping systematic review and call to action

Objective

To identify and map the extent to which trials for pain interventions in individuals with knee osteoarthritis (OA) track measures of sleep, characterize the type of sleep measure assessed, and assess their influence on pain-related effect sizes.

Design

A scoping review was conducted, searching seven bibliometric databases from 2000 to 2022. We included all randomized controlled trials with a primary purpose of assessing non-surgical pain management interventions for adults with knee OA. All non-surgical interventions and any comparator or control were included. Demographic data were pooled from all trials.

Results

926 trials conducted in 61 countries met eligibility. Nineteen trials (2.1%) recorded some form of sleep assessment. Eleven trials (1.2%) assessed a formal index of sleep disturbance collected at multiple time points. No trials formally assessed the influence of sleep on the primary pain outcome (e.g., as a potential mediator), nor met the most recent guidelines for core data element recommendations regarding sleep assessment.

Conclusion

This review highlights the paucity of sleep data captured and reported in randomized controlled trials for knee OA. The vast majority of trials addressing symptomatic knee OA do not capture sleep measures, significantly limiting the ability to accurately determine an intervention's effect on pain. Future research should include formal sleep-centric assessments measured at multiple time points to analyze sleep dysfunction and its relationship on treatment effects.

Exudate Absorbing and Antimicrobial Hydrogel Integrated with Multifunctional Curcumin-Loaded Magnesium Polyphenol Network for Facilitating Burn Wound Healing

Burns are among the most common causes of trauma worldwide. Reducing the healing time of deep burn wounds has always been a major challenge. Traditional dressings not only require a lengthy medical procedure but also cause unbearable pain and secondary damage to patients. In this study, we developed an exudate-absorbing and antimicrobial hydrogel with a curcumin-loaded magnesium polyphenol network (Cur-Mg@PP) to promote burn wound healing. That hydrogel was composed of an ε-poly-l-lysine (ε-PLL)/polymer poly(γ-glutamic acid) (γ-PGA) hydrogel (PP) and curcumin-loaded magnesium polyphenol network (Cur-Mg). Because of the strong water absorption property of ε-PLL and γ-PGA, Cur-Mg@PP powder can quickly absorb the wound exudate and transform into a moist and viscous hydrogel, thus releasing payloads such as magnesium ion (Mg2+) and curcumin (Cur). The released Mg2+ and Cur demonstrated good therapeutic efficacy on analgesic, antioxidant, anti-inflammation, angiogenesis, and tissue regeneration. Our findings provide a strategy for accelerating burn wound healing.

Curcumin reverses erastin-induced chondrocyte ferroptosis by upregulating Nrf2

Osteoarthritis (OA) is associated with ferroptosis, a newly discovered form of programmed cell death associated with lipid peroxidation. Curcumin, the main monomer component in turmeric rhizomes, possesses antioxidant and anti-ferroptosis properties, but its effect on ferroptosis in chondrocytes of OA is unknown. This study aimed to investigate the protective effect and potential mechanism of curcumin on chondrocytes induced by erastin, a ferroptosis inducer. CCK-8 assays were used to assess cell viability in mouse primary chondrocytes treated with 3.33 μM erastin alone or in combination with different doses of curcumin. Various parameters were detected, including LDH, SOD, GSH-PX, MDA, ROS and Fe2+ contents. The ferroptosis-related proteins, such as SLC7A11, GPX4, TFR1, ACSL4, and FTH1, were examined using immunofluorescence and western blotting. Nrf2 was knocked down using siRNA to explore the molecular mechanism through which curcumin protects chondrocytes from erastin-induced ferroptosis. In a mouse model of knee ferroptosis induced by intracavity injection of 10 μL erastin (5 mg/mL), HE staining, Safranin O-Fast Green staining, and immunohistochemistry were employed to evaluate articular cartilage injury. The results demonstrated that erastin significantly suppressed the expression of SOD, GSH-PX, SLC7A11, GPX4, and FTH1 while upregulating the levels of LDH, MDA, ROS, ACSL4, and TFR1 in chondrocytes. Moreover, erastin-induced chondrocyte ferroptosis, lipid ROS, and Fe2+ production were reversed by curcumin. Additionally, curcumin significantly upregulated the expression level of the Nrf2 gene and protein. Silencing Nrf2 reversed the protective effect of curcumin on erastin-induced chondrocyte ferroptosis. In animal experiments, silencing Nrf2 counteracted the impact and damage of curcumin on erastin-induced ferroptosis of cartilage tissue in vivo, leading to significant inhibition of OA progression. Taken together, these findings suggest that curcumin can inhibit chondrocyte ferroptosis by activating the Nrf2 signaling pathway, providing further insight into the regulatory mechanism of curcumin in OA and supporting its potential therapeutic use in OA treatment.

Natural anti-inflammatory products for osteoarthritis: From molecular mechanism to drug delivery systems and clinical trials

Osteoarthritis (OA) is a degenerative joint disease that affects millions globally. The present nonsteroidal anti-inflammatory drug treatments have different side effects, leading researchers to focus on natural anti-inflammatory products (NAIPs). To review the effectiveness and mechanisms of NAIPs in the cellular microenvironment, examining their impact on OA cell phenotype and organelles levels. Additionally, we summarize relevant research on drug delivery systems and clinical randomized controlled trials (RCTs), to promote clinical studies and explore natural product delivery options. English-language articles were searched on PubMed using the search terms "natural products," "OA," and so forth. We categorized search results based on PubChem and excluded "natural products" which are mix of ingredients or compounds without the structure message. Then further review was separately conducted for molecular mechanisms, drug delivery systems, and RCTs later. At present, it cannot be considered that NAIPs can thoroughly prevent or cure OA. Further high-quality studies on the anti-inflammatory mechanism and drug delivery systems of NAIPs are needed, to determine the appropriate drug types and regimens for clinical application, and to explore the combined effects of different NAIPs to prevent and treat OA.

Prevention and treatment of inflammatory arthritis with traditional Chinese medicine: Underlying mechanisms based on cell and molecular targets

Inflammatory arthritis, primarily including rheumatoid arthritis, osteoarthritis and ankylosing spondylitis, is a group of chronic inflammatory diseases, whose general feature is joint dysfunction with chronic pain and eventually causes disability in older people. To date, both Western medicine and traditional Chinese medicine (TCM) have developed a variety of therapeutic methods for inflammatory arthritis and achieved excellent results. But there is still a long way to totally cure these diseases. TCM has been used to treat various joint diseases for thousands of years in Asia. In this review, we summarize clinical efficacies of TCM in inflammatory arthritis treatment after reviewing the results demonstrated in meta-analyses, systematic reviews, and clinical trials. We pioneered taking inflammatory arthritis-related cell targets of TCM as the entry point and further elaborated the molecular targets inside the cells of TCM, especially the signaling pathways. In addition, we also briefly discussed the relationship between gut microbiota and TCM and described the role of drug delivery systems for using TCM more accurately and safely. We provide updated and comprehensive insights into the clinical application of TCM for inflammatory arthritis treatment. We hope this review can guide and inspire researchers to further explore mechanisms of the anti-arthritis activity of TCM and make a great leap forward in comprehending the science of TCM.

Beyond Seasoning-The Role of Herbs and Spices in Rheumatic Diseases

Although we have witnessed remarkable progress in understanding the biological mechanisms that lead to the development of rheumatic diseases (RDs), remission is still not achieved in a substantial proportion of patients with the available pharmacological treatment. As a consequence, patients are increasingly looking for complementary adjuvant therapies, including dietary interventions. Herbs and spices have a long historical use, across various cultures worldwide, for both culinary and medicinal purposes. The interest in herbs and spices, beyond their seasoning properties, has dramatically grown in many immune-mediated diseases, including in RDs. Increasing evidence highlights their richness in bioactive molecules, such as sulfur-containing compounds, tannins, alkaloids, phenolic diterpenes, and vitamins, as well as their antioxidant, anti-inflammatory, antitumorigenic, and anticarcinogenic properties. Cinnamon, garlic, ginger, turmeric, and saffron are the most popular spices used in RDs and will be explored throughout this manuscript. With this paper, we intend to provide an updated review of the mechanisms whereby herbs and spices may be of interest in RDs, including through gut microbiota modulation, as well as summarize human studies investigating their effects in Rheumatoid Arthritis, Osteoarthritis, and Fibromyalgia.

Anti-Osteoarthritic Effects of Prunella Vulgaris and Gentiana Lutea In Vitro and In Vivo

Osteoarthritis (OA) is the progressive destruction of articular cartilage with severe symptoms, including pain and stiffness. We investigated the anti-osteoarthritic effects of Prunella vulgaris (PV) and Gentiana lutea (GL) extract in primary cultured chondrocytes RAW 264.7 cells in vitro and destabilization of the medial meniscus (DMM)-induced OA mice in vivo. Primary chondrocytes were induced with IL-1β, and RAW 264.7 cells were treated with LPS and co-incubated with either individual extracts of PV and GL or different ratios of PV and GL mixture. For the OA animal model, the medial meniscus (DMM) was destabilized in 9-week-old male C57BL/6 mice. Treatment of individual PV and GL and combination of PV and GL extracts inhibited the mRNA expression level of COX2 in chondrocytes and RAW 264.7 cells. The optimized inhibitory effect was attained with a PV and GL combination at an 8:2 ratio (PG) without cytotoxic effects. PG extracts prevented the expression of catabolic factors (COX2, Mmp3, Mmp9, and Mmp13) and inflammatory mediator levels (PGE2 and collagenase). In addition, PG decreased subchondral sclerosis and increased BMD in the subchondral region of DMM-induced OA mice with protection of articular cartilage destruction by inhibiting inflammatory processes. This study suggests that PG may be an alternative medicinal herb for treatment of OA.

OA-Pain-Sense: Machine Learning Prediction of Hip and Knee Osteoarthritis Pain from IMU Data

Joint pain is a prominent symptom of Hip and Knee Osteoarthritis (OA), impairing patients’ movements and affecting the joint mechanics of walking. Self-report questionnaires are currently the gold standard for Hip OA and Knee OA pain assessment, presenting several problems, including the fact that older individuals often fail to provide accurate self-pain reports. Passive methods to assess pain are desirable. This study aims to explore the feasibility of OA-Pain-Sense, a passive, automatic Machine Learning-based approach that predicts patients’ self-reported pain levels using SpatioTemporal Gait features extracted from the accelerometer signal gathered from an anterior-posterior wearable sensor. To mitigate inter-subject variability, we investigated two types of data rescaling: subject-level and dataset-level. We explored six different binary machine learning classification models for discriminating pain in patients with Hip OA or Knee OA from healthy controls. In rigorous evaluation, OA-Pain-Sense achieved an average accuracy of 86.79% using the Decision Tree and 83.57% using Support Vector Machine classifiers for distinguishing Hip OA and Knee OA patients from healthy subjects, respectively. Our results demonstrate that OA-Pain-Sense is feasible, paving the way for the development of a pain assessment algorithm that can support clinical decision-making and be used on any wearable device, such as smartphones.

Efficacy and safety of curcuminoids alone in alleviating pain and dysfunction for knee osteoarthritis: a systematic review and meta-analysis of randomized controlled trials

Background

Curcuminoids (CURs) are the principal ingredients of Curcuma longa L. [Zingiberaceae] (CL)—an herbal plant used in east Asia to alleviate pain and inflammation. Thus far, the therapeutic effects of CURs for knee osteoarthritis (OA) uncovered by multiple reviews remained uncertain due to broadly involving trials with different agents-combined or CURs-free interventions. Therefore, we formed stringent selection criteria and assessment methods to summarize current evidence on the efficacy and safety of CURs alone in the treatment of knee OA.

Methods

A series of databases were searched for randomized controlled trials (RCTs) evaluating the efficacy and safety of CURs for knee OA. Clinical outcomes were evaluated using meta-analysis and the minimum clinically important difference (MCID) for both statistical and clinical significance.

Results

Fifteen studies with 1670 patients were included. CURs were significantly more effective than placebo in the improvements of VAS for pain ( WMD: − 1.77, 95% CI: − 2.44 to − 1.09), WOMAC total score ( WMD: − 7.06, 95% CI: − 12.27 to − 1.84), WOMAC pain score ( WMD: − 1.42, 95% CI: − 2.41 to − 0.43), WOMAC function score ( WMD: − 5.04, 95% CI: − 7.65 to − 2.43), and WOMAC stiffness score ( WMD: − 0.54, 95% CI: − 1.03 to − 0.05). Meanwhile, CURs were not inferior to NSAIDs in the improvements of pain- and function-related outcomes. Additionally, CURs did not significantly increase the incidence of adverse events (AEs) compared with placebo ( RR: 1.03, 95% CI: 0.69 to 1.53, P = 0.899, I² = 23.7%) and NSAIDs (RR: 0.71 0.65, 95% CI: 0.57 0.41 to 0.90 1.03).

Conclusions

CURs alone can be expected to achieve considerable analgesic and functional promotion effects for patients with symptomatic knee OA in short term, without inducing an increase of adverse events. However, considering the low quality and substantial heterogeneity of present studies, a cautious and conservative recommendation for broader clinical use of CURs should still be made. Further high-quality studies are necessary to investigate the impact of different dosages, optimization techniques and administration approaches on long-term safety and efficacy of CURs, so as to strengthen clinical decision making for patients with symptomatic knee OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03740-9.

Medicinal plants and their secondary metabolites in alleviating knee osteoarthritis: A systematic review

BACKGROUND

With the increasing ages of the general population, the incidence of knee osteoarthritis (KOA) is also rising, and KOA has become a major health problem worldwide. Recently, medicinal plants and their secondary metabolites have gained interest due to their activity in treating KOA. In this paper, a comprehensive systematic review of the literature was performed concerning the effects of medicinal plant extracts and natural compounds against KOA in recent years. The related molecular pathways of natural compounds against KOA were summarized, and the possible crosstalk among components in chondrocytes was discussed to propose possible solutions for the current situation of treating KOA.

PURPOSE

This review focused on the molecular mechanisms by which medicinal plants and their secondary metabolites act against KOA.

METHODS

Literature searches were performed in the PUBMED, Embase, Science Direct, and Web of Science databases for a 10-year period from 2011 to 2022 with the search terms "medicinal plants," "bioactive compounds," "natural products," "phytochemical," "knee osteoarthritis," "knee joint osteoarthritis," "knee osteoarthritis," "osteoarthritis of the knee," and "osteoarthritis of knee joint."

RESULTS

According to the results, substantial plant extracts and secondary metabolites show a positive effect in fighting KOA. Plant extracts and their secondary metabolites can affect the diagnostic and prognostic biomarkers of KOA. Natural products inhibit the expression of MMP1, MMP3, MMP19, syndecan IV, ADAMTS-4, ADAMTS-5, iNOS, COX-2, collagenases, IL-6, IL-1β, and TNF-α in vitro and in vivo and . Cytokines also upregulate the expression of collagen II and aggrecan. The main signaling pathways affected by the extracts and isolated compounds include AMPK, SIRT, NLRP3, MAPKs, PI3K/AKT, mTOR, NF-κB, WNT/β-catenin, JAK/STAT3, and NRF2, as well as the cell death modes apoptosis, autophagy, pyroptosis, and ferroptosis.

CONCLUSION

The role of secondary metabolites in different signaling pathways supplies a better understanding of their potential to develop further curative options for KOA.

Efficacy and Safety of Curcumin and Curcuma longa Extract in the Treatment of Arthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trial

Background

Modern pharmacological research found that the chemical components of Curcuma longa L. are mainly curcumin and turmeric volatile oil. Several recent randomized controlled trials (RCT) have shown that curcumin improves symptoms and inflammation in patients with arthritis.

Methods

Pubmed, Cochran Library, CNKI, and other databases were searched to collect the randomized controlled trials (RCTs). Then, the risk of bias of RCTs were assessed and data of RCTs were extracted. Finally, RevMan 5.3 was utilized for meta-analysis.

Results

Twenty-nine (29) RCTs involving 2396 participants and 5 types of arthritis were included. The arthritis included Ankylosing Spondylitis (AS), Rheumatoid Arthritis (RA), Osteoarthritis (OA), Juvenile idiopathic arthritis (JIA) and gout/hyperuricemia. Curcumin and Curcuma longa Extract were administered in doses ranging from 120 mg to 1500 mg for a duration of 4-36 weeks. In general, Curcumin and Curcuma longa Extract showed safety in all studies and improved the severity of inflammation and pain levels in these arthritis patients. However, more RCTs are needed in the future to elucidate the effect of Curcumin and Curcuma longa Extract supplementation in patients with arthritis, including RA, OA, AS and JIA.

Conclusion

Curcumin and Curcuma longa Extract may improve symptoms and inflammation levels in people with arthritis. However, due to the low quality and small quantity of RCTs, the conclusions need to be interpreted carefully.

Measurement properties of performance-based measures to assess physical function in knee osteoarthritis: A systematic review

OBJECTIVE

To systematically review the measurement properties of performance-based measures to assess physical function in people with knee osteoarthritis.

DATA SOURCES

PubMed, Web of Science, Embase, Scopus, CINAHL, and PsycINFO were searched in May 2022.

METHODS

This study was conducted in accordance with the guidelines recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Clinical trials on the psychometric properties of performance-based tools for measuring physical function in people with knee osteoarthritis were included. Two reviewers independently rated measurement properties using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN). "Best evidence synthesis" was made using COnsensus-based Standards for the selection of health Measurement INstruments outcomes and the quality of findings.

RESULTS

Thirty-six out of 3425 publications were eligible for inclusion. Thirty-two performance-based measures were evaluated including 26 single-activity measures and 6 multi-activity measures. Measurement properties evaluated included internal consistency (2 measures), reliability (23 measures), measurement error (20 measures), hypotheses testing for construct validity (22 measures), and responsiveness (23 measures). On balance of the limited evidence, the walk 40 m fast-paced test and 6-minute walking test were the best rated walking tests. The 30-second chair stand test and timed up and go test were the best rated sit-to-stand tests. The Performance Tests Measures and Physical Activity Restrictions may be the suitable multi-activity measures for knee osteoarthritis.

CONCLUSIONS

Further good quality research investigating the measurement properties, and in particular, the measurement error of performance-based measures in patients with knee osteoarthritis is needed.

Curcumin: Useful add-on for Rheumatic Diseases?

Plant-derived nutraceuticals are proposed as new key instruments to represent a profound “back to basics” shift in medical treatment. Data accumulated over the past ten years suggest that curcumin, the major active compound of the turmeric plant, has anti-inflammatory properties. It has yet to be determined whether the anti-inflammatory profile of curcumin is potent enough to justify the application of this substance as a nutritional supplement for patients with rheumatic diseases. To address this question, the most relevant in vitro studies that investigate the mechanism of action of curcumin were reviewed in this article. In addition, a total of 18 animal and human trials were evaluated. The pleiotropic, anti-inflammatory and immunomodulatory effects of curcumin were observed in animal studies. In addition, human trials demonstrated promising findings. In these studies, curcumin was able to reduce the expression of proinflammatory cytokines, lower the level of the C-reactive protein and improve clinical parameters. A limiting factor of the application of curcumin is the inconsistent bioavailability of the substance. Therefore, new formulations have been developed to improve the pharmacodynamic profile of curcumin. The future acceptance of the substance is dependent on new controlled clinical trials with a standardised formulation of curcumin administered as well as standard of care.