Double-blind clinical evaluation of oral glucosamine sulphate in the basic treatment of osteoarthrosis

Effects of Glucosamine in the Temporomandibular Joint Osteoarthritis: A Review

Osteoarthritis in the temporomandibular joint (TMJ) is a chronic disease characterized by irreversible damage to articular surfaces, including inflammation, loss of articular cartilage, and subchondral bone alterations, which would be radiographically evident only in later stages. Symptomatic slow-acting so-called nutraceutical drugs have been proposed as a treatment for osteoarthritis in comparison to non-steroidal anti-inflammatory drugs (NSAID) because of their appreciable safety profile even in long-term intake. Glucosamine, being one among them, proved highly efficient in knee osteoarthritis. However, its application in TMJ osteoarthritis dates back only to 2001 and is still inconclusive in its efficiency even with systematic reviews, in restoring the structural and functional aspects of damaged TMJ. Glucosamine, being a natural compound and also a contributor to building the matrix of articular cartilage, can be utilized effectively for TMJ osteoarthritis as an adjunct along with other conventional treatment modalities available till now, which also have moderate prognosis in most of the clinical scenarios. This review summarizes data relating to the mechanism of osteoarthritis and its management using glucosamine formulations. The beneficial effects of glucosamine on the pathophysiology of TMJ osteoarthritis are possibly due to its contribution to hyaluronic acid regulation and in establishing a proper balance between anabolism/catabolism in the articular tissues.

Safety of Symptomatic Slow-Acting Drugs for Osteoarthritis: Outcomes of a Systematic Review and Meta-Analysis

BACKGROUND

Symptomatic slow-acting drugs for osteoarthritis (SYSADOAs) are an important drug class in the treatment armamentarium for osteoarthritis (OA).

OBJECTIVE

We aimed to re-assess the safety of various SYSADOAs in a comprehensive meta-analysis of randomized placebo-controlled trials, using, as much as possible, data from full safety reports.

METHODS

We performed a systematic review and random-effects meta-analyses of randomized, double-blind, placebo-controlled trials that assessed adverse events (AEs) with various SYSADOAs in patients with OA. The databases MEDLINE, Cochrane Central Register of Controlled Trials (Ovid CENTRAL) and Scopus were searched. The primary outcomes were overall severe and serious AEs, as well as AEs involving the following Medical Dictionary for Regulatory Activities (MedDRA) system organ classes (SOCs): gastrointestinal, cardiac, vascular, nervous system, skin and subcutaneous tissue, musculoskeletal and connective tissue, renal and urinary system.

RESULTS

Database searches initially identified 3815 records. After exclusions according to the selection criteria, 25 studies on various SYSADOAs were included in the qualitative synthesis, and 13 studies with adequate data were included in the meta-analyses. Next, from the studies previously excluded according to the protocol, 37 with mainly oral nonsteroidal anti-inflammatory drugs (NSAIDs) permitted as concomitant medication were included in a parallel qualitative synthesis, from which 18 studies on various SYSADOAs were included in parallel meta-analyses. This post hoc parallel inclusion was conducted because of the high number of studies allowing concomitant anti-OA medications. Indeed, primarily excluding studies with concomitant anti-OA medications was crucial for a meta-analysis on safety. The decision for parallel inclusion was made for the purpose of comparative analyses. Glucosamine sulfate (GS), chondroitin sulfate (CS) and avocado soybean unsaponifiables (ASU; Piascledine®) were not associated with increased odds for any type of AEs compared with placebo. Overall, with/without concomitant OA medication, diacerein was associated with significantly increased odds of total AEs (odds ratio [OR] 2.22; 95% confidence interval [CI] 1.58-3.13; I2 = 52.8%), gastrointestinal disorders (OR 2.85; 95% CI 2.02-4.04; I2 = 62.8%) and renal and urinary disorders (OR 3.42; 95% CI 2.36-4.96; I2 = 17.0%) compared with placebo. In studies that allowed concomitant OA medications, diacerein was associated with significantly more dermatological disorders (OR 2.47; 95% CI 1.42-4.31; I2 = 0%) and more dropouts due to AEs (OR 3.18; 95% CI 1.85-5.47; I2 = 13.4%) than was placebo. No significant increase in serious or severe AEs was found with diacerein versus placebo.

CONCLUSIONS

GS and CS can be considered safe treatments for patients with OA. All eligible studies on ASU included in our analysis used the proprietary product Piascledine® and allowed other anti-OA medications; thus, the safety of ASU must be confirmed in future studies without concomitant anti-OA medications. Given the safety concerns with diacerein, its usefulness in patients with OA should be assessed, taking into account individual patient characteristics.

Efficacy and safety of glucosamine, diacerein, and NSAIDs in osteoarthritis knee: a systematic review and network meta-analysis

Background

To conduct a systematic review and network meta-analysis of randomized controlled trials (RCTs) with the aims of comparing relevant clinical outcomes (that is, visual analog scores (VAS), total and sub-Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) scores, Lequesne algofunctional index, joint space width change, and adverse events) between diacerein, glucosamine, and placebo.

Methods

Medline and Scopus databases were searched from inception to 29 August 2014, using PubMed and Scopus search engines and included RCTs or quasi-experimental designs comparing clinical outcomes between treatments. Data were extracted from original studies. A network meta-analysis was performed by applying weight regression for continuous outcomes and a mixed-effect Poisson regression for dichotomous outcomes.

Results

Thirty-one of 505 identified studies were eligible. Compared to placebo, glucosamine showed a significant improvement with unstandardized mean differences (UMD) in total WOMAC, pain WOMAC, function WOMAC, and Lequesne score of −2.49 (95% confidence interval (CI) −4.14, −0.83), −0.75 (95% CI: −1.18, −0.32), −4.78 (95% CI: −5.96, −3.59), and −1.03 (95% CI: −1.34, −0.72), respectively. Diacerein clinically improves visual analog scores, function WOMAC, and stiffness WOMAC with UMD values of −2.23 (95% CI: −2.82, −1.64), −6.64 (95% CI: −10.50, −2.78), and −0.68 (95% CI: −1.20, −0.16) when compared to placebo.

Conclusions

The network meta-analysis suggests that diacerein and glucosamine are equally efficacious for symptom relief in knee OA, but that the former has more side effects.

Electronic supplementary material

The online version of this article (doi:10.1186/s40001-015-0115-7) contains supplementary material, which is available to authorized users.

The dissolution and solid-state behaviours of coground ibuprofen-glucosamine HCl

The cogrinding technique is one of most effective methods for improving the dissolution of poorly water-soluble drugs and it is superior to other approaches from an economical as well as an environmental standpoint, as the technique does not require any toxic organic solvents. Present work explores the role of d-glucosamine HCl (GL) as a potential excipient to improve dissolution of a low melting point drug, ibuprofen (Ibu), using physical mixtures and coground formulations. The dissolution of the poorly soluble drug has been improved by changing the ratio of Ibu:GL and also grinding time. The results also showed that although GL can enhance the solubility of Ibu, it also reduces pH around the Ibu particles which led to poor dissolution performance when the concentration of GL is high. The effect of GL on the solubility of Ibu could be misleading if the pH of the final solution was not measured. Grinding reduced the particle size of GL significantly but in case of Ibu it was less effective. Solid state analysis (XRPD, DSC, and FT-IR) showed that ibuprofen is stable under grinding conditions, but the presence of high concentration of GL in samples subjected to high grinding times caused changes in FT-IR spectrum of Ibu which could be due to intermolecular hydrogen bond or esterification between the carboxylic acid group in the ibuprofen and hydroxyl group in the GL.

Suppressive effects of D-glucosamine on the 5-HT sensitive nociceptive units in the rat tooth pulpal nerve

It is well known that D-glucosamine hydrochloride (DGL) has a variety of biological activities and is regarded as a nutritional supplement effective in improving various disorders, including osteoarthritis and atherosclerosis. Although it has been reported that DGL has a significant pain relief effect in treating osteoarthritis, little is known about the characteristics of the effects of this compound on dental pain. The present study was undertaken to evaluate the applicability of DGL as a medicament to control pulpalgia. Using an in vitro rat mandible-inferior alveolar nerve preparation (jaw-nerve preparation), we evaluated the effects of DGL on 5-hydroxytryptamine (5-HT) sensitive nociceptive responses in the tooth pulpal nerve. 5-HT-induced nociceptive responses were fairly suppressed by direct application of DGL, suggesting that DGL have a pain relief effect on patients with dental pain.

The dissolution enhancement of piroxicam in its physical mixtures and solid dispersion formulations using gluconolactone and glucosamine hydrochloride as potential carriers

The solid dispersion technique is one of the most effective methods for improving the dissolution rate of poorly water-soluble drugs; however this is reliant on a suitable carrier and solvent being selected. The work presented explores amino sugars (d-glucosamine HCl and d-gluconolactone) as potential hydrophilic carriers to improve dissolution rate of a poorly water-soluble drug, piroxicam, from physical mixtures and solid dispersion formulations. Solid dispersions of the drug and carrier were prepared using different ratios by the conventional solvent evaporation method. Acetone was used as solvent in the preparation of solid dispersions. Physical mixtures of piroxicam and carrier were also prepared for comparison. The properties of all solid dispersions and physical mixtures were studied using a dissolution tester, Fourier transform infrared, XRD, SEM and differential scanning calorimetry. These results showed that the presence of glucosamine or gluconolactone can increase dissolution rate of piroxicam compared to pure piroxicam. Glucosamine or Gluconolactone could be used as carrier in solid dispersion formulations and physical mixtures to enhance the dissolution rate. Solid state studies showed that no significant changes occurred for piroxicam in physical mixtures and solid dispersion.

Efficacies of different preparations of glucosamine for the treatment of osteoarthritis: a meta-analysis of randomised, double-blind, placebo-controlled trials

OBJECTIVE

To determine the efficacies of different preparations of glucosamine for the treatment of osteoarthritis (OA).

METHODS

Systematic searches of the bibliographic databases Medline, Embase, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews for randomised, double-blind, placebo-controlled trials (RCTs) concerning glucosamine treatment of OA. Effect size (ES) was estimated using Cohen's standardised mean difference. Consistency was evaluated via the I(2) index.

RESULTS

Nineteen trials (3159 patients) contributed to the meta-analysis, revealing a large degree of inconsistency among the trials in terms of pain-reduction outcome: the combined ES in glucosamine sulphate (GS) trials was -0.22 [95% confidence intervals (CI) -0.48, 0.04], I(2) was 82.3%. The combined ES in glucosamine hydrochloride (GH) trials was -0.03 (95% CI -0.14, 0.08), with an absence of heterogeneity. No treatment ES was observed [-0.38 (95% CI -0.99, 0.23)] favouring GS in trials of less than 24 weeks duration and the I(2) remained high (I(2) = 88.5%). No significant treatment ES -0.09 (95% CI -0.21, 0.03) was observed in trials of more than 24 weeks duration compared with placebo, with a heterogeneity of zero. In terms of function-modifying outcomes, GS showed no significant effect on Lequesne Index reduction vs. placebo in trials of less than 24 weeks duration (ES -0.55 (95% CI -1.22, 0.11)) with a high degree of heterogeneity (I(2) = 92.9%). Pooling data from studies with durations of more than 24 weeks presented a significant combined ES of -0.36 (95% CI: -0.56, -0.17) with an absence of heterogeneity. No risk of publication bias could be detected using Egger test.

CONCLUSIONS

GH is ineffective for pain reduction in patients with knee OA. GS may have function-modifying effects in patients with knee OA when administered for more than 6 months. However, it showed no pain-reduction benefits after 6 months of therapy.

Difficulties with assessing the benefit of glucosamine sulphate as a treatment for osteoarthritis

Osteoarthritis is a chronic disease with a major impact on quality of life for a large proportion of the population. It is a disease for which to date there has been no disease-modifying therapy identified. As a result of its physiological role in articular cartilage, glucosamine sulphate has been postulated as a treatment for osteoarthritis. Claims have included symptomatic relief and even reduction in the rate of disease progression. Despite promising in vitro studies, however, the role of glucosamine sulphate in the management of osteoarthritis remains unclear. Studies addressing this issue have generated a wide range of conclusions, and these are discussed here. Methodological issues need to be addressed in order to gauge whether there is true benefit. On current evidence, it would appear that the benefits of dietary supplementation with glucosamine sulphate are limited to mild symptomatic relief, while a disease-modifying agent for this disease remains elusive.

Evaluation of the chondroprotective effects of glucosamine and fish collagen peptide on a rabbit ACLT model using serum biomarkers

The aim of this study was to investigate the correlations of severity of osteoarthritis (OA) and serum biomarkers including keratan sulfate (KS), hyaluronic acid (HA) and chondroitin sulfate (CS) 846 epitope. We also investigated the effect of glucosamine and fish collagen peptide (FCP) on OA. OA was induced in 12 rabbits (12 weeks of age) by anterior cruciate ligament transection (ACLT). After the surgery, the rabbits were orally administered FCP (F group), glucosamine (G group) or FCP and glucosamine (FG group) for 4 weeks. The control group was provided water ad libitum (C group). Blood was collected before surgery (pre-ACLT) and before euthanasia (post-ACLT) for serum marker measurement. Biomarker levels were measured by using commercial kits. We evaluated OA severity both macroscopically and histologically. Macroscopic evaluation showed mildly eroded condylar surfaces in the C group. Histological findings were significantly different from the FG and other groups. There were no significant differences between each group at post-ACLT in terms of serum KS, HA and CS 846. Histological assessment and serum biomarker measurements performed at post-ACLT showed a significant correlation between HA concentration and OA severity. Variations in the CS 846 concentration at pre-ACLT and post-ACLT were significantly correlated with OA severity. Administration of glucosamine and FCP had chondroprotective effects in the ACLT model. Serum biomarker concentrations were significantly correlated with cartilage injury. Serum biomarker measurement would be useful for monitoring articular cartilage damage in the clinical setting.

Correlation of plasma amino acid concentrations and chondroprotective effects of glucosamine and fish collagen peptide on the development of osteoarthritis

We investigated the correlation of plasma amino acid concentrations and the effects of glucosamine and fish collagen peptide (FCP) on osteoarthritis (OA). OA was induced according to the rabbit anterior cruciate ligament transection (ACLT) model. After surgery, the rabbits were orally administered FCP (F group), glucosamine (G group) or both (FG group) for 4 weeks. The control group (C group) was not administered anything. Blood was collected before surgery (pre-ACLT) and before euthanasia (post-ACLT). Changes in the alanine, threonine and methionine concentrations were significant between pre- and post-ACLT. The correlation between the histological assessment and arginine concentration post-ACLT was significant. These findings indicate that measurement of plasma amino acids is useful for evaluation of the efficacy of intervention for OA.

A comprehensive review of oral glucosamine use and effects on glucose metabolism in normal and diabetic individuals

Glucosamine (GlcN) is a widely utilized dietary supplement that is used to promote joint health. Reports that oral GlcN supplementation at usual doses adversely affects glucose metabolism in subjects with impaired glucose tolerance have raised concerns that GlcN should be contraindicated in individuals with diabetes and those at risk for developing it. This review addresses its potential, when used at typical doses, to affect glucose metabolism and insulin sensitivity in healthy individuals and those with diabetes or 'pre-diabetes'. Publicly available scientific information and data on GlcN were systematically compiled using the electronic search tool, Dialog , and reviewed with special emphasis on human studies. In long-term clinical trials, including those containing subjects with type 2 diabetes or 'pre-diabetes', GlcN produced a non-significant lowering of fasting blood glucose concentrations in all groups of subjects treated for periods of up to 3 years. Owing to limitations in study design, conclusions based on studies that report adverse affects of GlcN on insulin sensitivity and glucose tolerance in pre-diabetic subjects are suspect. However, no definitive long-term studies of GlcN use for individuals with pre-diabetes are available. Nevertheless, based on available evidence, we conclude that GlcN has no effect on fasting blood glucose levels, glucose metabolism, or insulin sensitivity at any oral dose level in healthy subjects, individuals with diabetes, or those with impaired glucose tolerance.

Modern management of mild-to-moderate joint pain due to osteoarthritis: a holistic approach

Osteoarthritis (OA) is the most common form of arthritis and it is often associated with significant disability and impaired quality of life. Once thought to be caused by an age-related 'wearing out' of articular cartilage, it is now recognized to be a dynamic process in which cartilage degradation alternates with repair. Several expert guidelines for the management of OA exist, which concur in their recommendations for a stepwise approach to the employment of pharmacological agents and the introduction of suggestions to extend the use of agents such as topical non-steroidal anti-inflammatory drugs, especially for mild-to-moderate forms of the disease. They also emphasize the importance of non-pharmacological measures, such as nutraceuticals, education, diet, exercise and the use of aids in improving signs and symptoms and slowing progression. In many countries, effective medicinal and nutraceutical agents are available 'over-the-counter'. This review explains the modern approach to the management of mild-to-moderate osteoarthritic pain.

Effects of adjunct glucosamine sulfate on relapsing-remitting multiple sclerosis progression: preliminary findings of a randomized, placebo-controlled trial

OBJECTIVES

Glucosamine has been safely used to relieve osteoarthritis. The aim of this preliminary study was to evaluate the effect of glucosamine sulfate in combination with current disease modifying therapy on the prevention of progression of relapsing-remitting multiple sclerosis (RRMS).

METHODS

A phase II double-blind placebo-controlled randomized clinical trial conducted between February and October 2007 included 97 patients with confirmed RRMS aged 17-55 years. They were randomly allocated to receive 6 months of treatment with either oral glucosamine sulfate (1000 mg/day) or placebo combined with disease-modifying therapy. Response to treatment was assessed at 6 months. Primary and secondary outcome measures were number of relapse and changes in mean Expanded Disability Status Scale (EDSS).

RESULTS

In 46 patients treated with glucosamine sulfate, mean (SD) relapse rate decreased from 1.1 (0.7) at baseline to 0.4 (0.5) at the end of study period (P<0.05). In the 51 patients treated with placebo, the mean (SD) relapse rate did not change. After 6 months, 63.0% of patients receiving glucosamine sulfate remained relapse-free compared to 54.9% of those given placebo (P>0.05). Average EDSS at the end of trial did not differ between groups (mean difference: -0.1; 95% CI: -0.5-0.2).

DISCUSSION

Adding glucosamine sulfate to routine disease modifying-therapy had no significant effect on relapse rate or disease progression during the treatment period. A larger phase-III multicenter study of glucosamine sulfate in RRMS is warranted to more assess the efficacy of this intervention.

Acute liver injury associated with the use of herbal preparations containing glucosamine: three case studies

The use of complementary and alternative medicines is becoming increasingly popular in Western society. As a result the number of reported adverse reactions is increasing. Glucosamine is a herbal remedy commonly used to ease joint pain in osteoarthritis, and only two previous reports of hepatotoxicity have been published in the scientific literature. The present report describes three patients who developed acute liver injury following exposure to glucosamine; one patient made a complete recovery on cessation of ingestion, the second developed chronic hepatitis and the third died following progression to fulminant hepatic failure. A diagnosis of glucosamine-induced hepatotoxicity was made based on the temporal relationship between onset of liver injury and glucosamine ingestion, exclusion of all other potential aetiologies and, in the two surviving cases, improvement in condition on withdrawal of the supplement.

An oral nutraceutical containing antioxidants, minerals and glycosaminoglycans improves skin roughness and fine wrinkles

Various nutraceuticals (dietary supplements) are claimed to have cutaneous antiageing properties, however, there are a limited number of research studies supporting these claims. The objective of this research was to study the effectiveness of an oral nutraceutical containing antioxidants, minerals and glycosaminoglycans on cutaneous ageing. In this double-blind, placebo-controlled trial, 60 women aged 35-60 years were randomized to receive oral dietary supplement (n = 30) or placebo (n = 30), once daily for 12 weeks. The depth of skin roughness and fine wrinkles were measured using surface evaluation of skin parameters for living skin (Visioscan) at baseline, and at the 4, 8 and 12 weeks of treatment. Surface evaluation using a replica film (Visiometer) at baseline and at the 12th week of treatment was also carried out. Statistical differences in objective skin improvement were assessed by the independent t-test. The volunteers' satisfaction was tested using the chi-squared test. The baseline depth of skin roughness and fine wrinkles in the treatment group and the placebo group were 100.5 and 100 mum, respectively. At the end of the study, the depth of skin roughness and fine wrinkles in the treatment group showed a 21.2% improvement, whereas improvement in the control group was 1.7%. This difference was statistically significant (P < 0.001). With regard to the volunteers' satisfaction, there was no statistically significant decrease in the homogenization of skin colour, however, a statistically significant reduction in pore size and depth of skin roughness and fine wrinkles were observed (P < 0.05). No side effects were noted throughout the study. The oral dietary supplement containing antioxidants, minerals and glycosaminoglycans improved skin roughness and fine wrinkles but did not affect skin colour change in female volunteers.

Review article: Glucosamine

It has been claimed that glucosamine is able to alleviate pain, slow down losses of, and even restore articular cartilage in patients with damaged or osteoarthritic joints. It is classified as a food additive or nutraceutical; therefore manufacturers do not need to comply with the same regulations that apply for quality assurance within the pharmaceutical industry. Osteoarthritis can be managed by pharmacological and non-pharmacological methods. It is controversial whether glucosamine sulphate is the first structure-modifying drug commercially available. Little evidence suggests that glucosamine is superior to a placebo treatment in restoring articular cartilage.

O-linked N-acetylglucosaminylation of Sp1 inhibits the human immunodeficiency virus type 1 promoter

Human immunodeficiency virus type 1 (HIV-1) gene expression and replication are regulated by the promoter/enhancer located in the U3 region of the proviral 5' long terminal repeat (LTR). The binding of cellular transcription factors to specific regulatory sites in the 5' LTR is a key event in the replication cycle of HIV-1. Since transcriptional activity is regulated by the posttranslational modification of transcription factors with the monosaccharide O-linked N-acetyl-D-glucosamine (O-GlcNAc), we evaluated whether increased O-GlcNAcylation affects HIV-1 transcription. In the present study we demonstrate that treatment of HIV-1-infected lymphocytes with the O-GlcNAcylation-enhancing agent glucosamine (GlcN) repressed viral transcription in a dose-dependent manner. Overexpression of O-GlcNAc transferase (OGT), the sole known enzyme catalyzing the addition of O-GlcNAc to proteins, specifically inhibited the activity of the HIV-1 LTR promoter in different T-cell lines and in primary CD4(+) T lymphocytes. Inhibition of HIV-1 LTR activity in infected T cells was most efficient (>95%) when OGT was recombinantly overexpressed prior to infection. O-GlcNAcylation of the transcription factor Sp1 and the presence of Sp1-binding sites in the LTR were found to be crucial for this inhibitory effect. From this study, we conclude that O-GlcNAcylation of Sp1 inhibits the activity of the HIV-1 LTR promoter. Modulation of Sp1 O-GlcNAcylation may play a role in the regulation of HIV-1 latency and activation and links viral replication to the glucose metabolism of the host cell. Hence, the establishment of a metabolic treatment might supplement the repertoire of antiretroviral therapies against AIDS.

Glucosamine/chondroitin combined with exercise for the treatment of knee osteoarthritis: a preliminary study

OBJECTIVE

This preliminary study sought to determine whether using 1500/1200mg of glucosamine hydrochloride and chondroitin sulfate (GH/CS) is effective, both separately and combined with exercise, compared to a placebo plus exercise program in improving physical function, pain, strength, balance, and mobility in older adults with knee osteoarthritis (OA).

METHODS

This double-blind, placebo-controlled, randomized clinical trial lasted 12 months. Participants included 89 older adults (age>/=50 years) with knee OA randomized to either GH/CS or placebo group. Phase I was a 6-month trial comparing the effects of assignment to either GH/CS or placebo. Phase II added 6 months of exercise for both groups. The primary outcome measure was Western Ontario and McMaster University Osteoarthritis Index (WOMAC) function, and secondary outcome measures included WOMAC pain, 6-min walk, balance, and knee strength.

RESULTS

Of the 89 randomized participants, 72 (81%) completed the study. The median pill compliance was 94% and 95% in Phase I, and, in Phase II, 97% and 91% for the GH/CS and placebo groups, respectively. Median exercise compliance during Phase II was 77% for the GH/CS group and 78% for the placebo group. WOMAC function and pain did not differ significantly between the groups at 6- or 12-month follow-up. There were also no significant differences between the groups in 6-min walk or knee strength; however, balance was better in the placebo group with approximately a 10% difference compared to the GH/CS group.

CONCLUSIONS

The GH/CS group was not superior to the placebo group in function, pain, or mobility after both phases of the intervention (pill only and pill plus exercise).

Glucosamine for pain in osteoarthritis: why do trial results differ?

OBJECTIVE

Investigators in trials of glucosamine report a range of estimates for efficacy, making conclusions difficult. We undertook this study to identify factors that explain heterogeneity in trials of glucosamine.

METHODS

We searched for reports of trial results in Ovid Medline, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and proceedings of scientific conferences. We selected reports of randomized, double-blind, placebo-controlled trials of glucosamine for pain from osteoarthritis of the knee or hip. We extracted data regarding features of design, subjects, and markers of industry involvement, including industry funding, whether a drug was supplied by industry, industry participation, and industry-affiliated authorship. We examined which factors best accounted for differences in the effect sizes of studies grouped by these characteristics, and we examined changes in I(2), a measure of heterogeneity.

RESULTS

Fifteen trials met our inclusion criteria. The summary effect size was 0.35 (95% confidence interval 0.14, 0.56). I(2) was 0.80. Except for allocation concealment, no feature of study design explained this substantial heterogeneity. Summary effect sizes ranged from 0.05 to 0.16 in trials without industry involvement, but the range was 0.47-0.55 in trials with industry involvement. The effect size was 0.06 for trials using glucosamine hydrochloride and 0.44 for trials using glucosamine sulfate. Trials using Rottapharm products had an effect size of 0.55, compared with 0.11 for the rest.

CONCLUSION

Heterogeneity among trials of glucosamine is larger than would be expected by chance. Glucosamine hydrochloride is not effective. Among trials with industry involvement, effect sizes were consistently higher. Potential explanations include different glucosamine preparations, inadequate allocation concealment, and industry bias.

The effects of glucosamine hydrochloride on subchondral bone changes in an animal model of osteoarthritis

OBJECTIVE

To quantify periarticular subchondral bone changes in a rabbit model of experimental osteoarthritis (OA), and to determine the effects of continuous administration of a clinically relevant dose of glucosamine HCl on subchondral bone changes in this model.

METHODS

Anterior cruciate ligament transection (ACLT) was performed on the left femorotibial joints of 16 rabbits to induce OA. Ten rabbits that did not undergo ACLT served as unoperated controls. Eight rabbits that underwent ACLT and 6 control rabbits were treated with 100 mg of glucosamine daily, and the others were given a placebo. The articular cartilage was evaluated macroscopically and graded at the time of necropsy, 8 weeks after ACLT. Bone mineral density (BMD) was measured using dual-energy x-ray absorptiometry on the dissected distal femur and proximal tibia. Subchondral trabecular bone turnover, architecture, and connectivity, as well as subchondral plate thickness and mineralization were studied on the undecalcified tibia sections from each animal.

RESULTS

Eight weeks after ACLT, most of the operated joints had various degrees of cartilage damage and fibrillation. Compared with the control group, the ACLT group had significantly increased subchondral bone turnover and lower BMD, bone volume, connectivity, and bone mineralization. The high bone turnover was significantly reduced in glucosamine-treated animals that underwent ACLT. In fact, there were no significant differences between the ACLT/glucosamine group and the control/glucosamine group in most of the bone parameters studied.

CONCLUSION

This study shows that subchondral bone turnover, structure, and mineralization are significantly altered in the early stages of experimental OA, and that these changes are attenuated by glucosamine treatment.

The utility of nutraceuticals in the treatment of osteoarthritis

Osteoarthritis (OA) treatment is limited by the inability of prescribed medications to alter disease outcome. As a result, patients with OA often take food substances called nutraceuticals in an attempt to affect the structural changes that occur within a degenerating joint. The role of nutraceuticals in OA management can be defined only by an evidence-based approach to support their use. This paper reviews the clinical trials studying glucosamine, chondroitin sulfate, vitamin C, vitamin E, and avocado-soybean unsaponifiables. It highlights the need for additional randomized, placebo-controlled trials to further define the utility of nutraceuticals in OA treatment.

Risk assessment for glucosamine and chondroitin sulfate

Glucosamine and chondroitin sulfate are two popular dietary ingredients present in dietary supplements intended to support joint health. A large body of human and animal research suggests that oral intakes of these ingredients, either alone or in combination, reduces joint pain and improves mobility in persons with osteoarthritis. The increased awareness and use of these ingredients in dietary supplements warrant a comprehensive review of their safety. Systematic evaluation of the research designs and data do not provide a basis for risk assessment and the usual safe upper level of intake (UL) derived from it unless the newer methods described as the observed safe level (OSL) or highest observed intake (HOI) are utilized. The OSL risk assessment method indicates that the evidence strongly supports safety at intakes up to 2000 mg/d for glucosamine, and 1200 mg/d for chondroitin sulfate, and these levels are identified as the respective OSL. These values represent the highest levels tested in human clinical trials. The complete absence of adverse effects at these levels supports a confident conclusion of their long-term safety.

Predictors of symptomatic response to glucosamine in knee osteoarthritis: an exploratory study

OBJECTIVE

To evaluate whether patient characteristics and/or radiographic disease patterns predict symptomatic response to treatment with glucosamine in osteoarthritis (OA) of the knee.

DESIGN

Exploratory prospective correlational study.

SETTING

Institutional.

PATIENTS

39 participants with chronic knee pain from the local community.

INTERVENTIONS

Glucosamine sulphate (1.5 g/day) for 12 weeks.

MAIN OUTCOME MEASURES

Pain and physical function were assessed with visual analogue scales (VASs) and participant-perceived global change scores (GCSs). Regression modelling evaluated the relationship between treatment outcome and age, body mass index (BMI), pain and function self-efficacy and presence/absence of osteophytes in the medial and lateral tibiofemoral joint (TFJ) and patellofemoral joint (PFJ) compartments.

RESULTS

13 (33%) participants were men. The mean (SD) age and BMI were 53.6 (13.1) years and 27.9 (4.6) kg/m(2), respectively. 13 (33%), 19 (49%) and 24 (62%) participants had medial TFJ, lateral TFJ and PFJ osteophytes, respectively. Glucosamine significantly improved pain (mean change on VAS = -1.4, 95% CI -0.6 to -2.2; p = 0.002) and activity restriction (-1.9, 95% CI -1.0 to -2.8; p<0.001). At 12 weeks, 30 (77%) and 27 (69%) participants reported improvement in pain and physical function, respectively. Regression modelling showed that no evaluated variables predicted change in pain on VAS. Decreased function self-efficacy, presence of PFJ osteophytes and absence of medial TFJ osteophytes predicted functional improvement on VAS. BMI, pain self-efficacy and function self-efficacy predicted improvement in pain by GCS.

CONCLUSIONS

Although glucosamine significantly improved symptoms, most of the variance in outcome at 12 weeks was unexplained by the predictors evaluated. However, glucosamine may be more effective at improving symptoms in patients with knee OA who have a lower BMI, PFJ osteophytes and lower functional self-efficacy.

Short-term efficacy of pharmacotherapeutic interventions in osteoarthritic knee pain: A meta-analysis of randomised placebo-controlled trials

BACKGROUND

Pain is the most debilitating symptom in osteoarthritis of the knee (OAK).

AIM AND METHODS

To determine the short-term pain-relieving effects of seven commonly used pharmacological agents for OAK pain by performing a systematic review of randomised placebo-controlled trials.

RESULTS

In total, 14,060 patients in 63 trials were evaluated. Opioids and oral NSAIDs therapy in patients with moderate to severe pain (mean baseline 64.3 and 72.8 mm on VAS respectively) had maximum efficacies compared to placebo at 2-4 weeks of 10.5 mm [95% CI: 7.4-13.7] and 10.2 mm [95% CI: 8.8-11.2] respectively. The efficacy of opioids may be inflated by high withdrawal rates (24-50%) and "best-case" scenarios reported in intention-to-treat analyses. In patients with moderate pain scores on VAS (mean range from 51 to 57 mm), intra-articular steroid injections and topical NSAIDs had maximum efficacies at 1-3 weeks of 14.5mm [95% CI: 9.7-19.2] and 11.6 mm [95% CI: 7.4-15.7], respectively. Paracetamol, glucosamin sulphate and chondroitin sulphate had maximum mean efficacies at 1-4 weeks of only 4.7 mm or lower. Heterogeneity tests revealed that best efficacy values of topical NSAIDs may be slightly deflated, while data for oral NSAIDs may be slightly inflated due to probable patient selection bias.

CONCLUSION

Clinical effects from pharmacological interventions in OAK are small and limited to the first 2-3 weeks after start of treatment. The pain-relieving effects over placebo in OAK are smaller than the patient-reported thresholds for relevant improvement.

Early relief of osteoarthritis symptoms with a natural mineral supplement and a herbomineral combination: a randomized controlled trial [ISRCTN38432711]

BACKGROUND

This study was designed to determine if a natural mineral supplement, sierrasil, alone and in combination with a cat's claw extract (Uncaria guianensis), vincaria, has therapeutic potential in mild to moderate osteoarthritis of the knee.

METHODS

Patients (n = 107) with mild to moderate osteoarthritis of the knee were randomly assigned to one of 4 groups; high dose sierrasil (3 g/day), low dose sierrasil (2 g/day), low dose sierrasil (2 g/day) + cat's claw extract (100 mg/day) or placebo, administered for 8 weeks. Treatment was double blinded. Primary efficacy variables were WOMAC scores (A, B, C and total). Visual analog score (VAS) for pain, consumption of rescue medication (paracetamol), and tolerability were secondary variables. Safety measures included vital signs and laboratory-based assays.

RESULTS

Ninety-one of the 107 patients successfully completed the protocol. All four groups showed improvement in WOMAC and VAS scores after 8 weeks (p < 0.001), in all 3 groups receiving sierrasil the magnitude of benefits were greater vs. placebo (WOMAC Total 38-43% vs. 27%) but this was not statistically significant. In reference to baseline values sierrasil treated groups had a considerably faster onset of benefits. Placebo-treated individuals failed to show significant benefits at 4 weeks (11% reduction in total WOMAC). In contrast, after 1 or 2 weeks of therapy all the sierrasil groups displayed significant reductions in WOMAC scores (p < 0.05) and at week 4 displayed a 38-43% improvement. VAS was significantly improved at 4 weeks in all groups (p < 0.001) but was significantly greater in all sierrasil groups compared to placebo (p < 0.05). Rescue medication use was 28-23% lower in the herbomineral combination and high dose sierrasil groups although not statistically different from placebo (P = 0.101 and P = 0.193, respectively). Tolerability was good for all groups, no serious adverse events were noted and safety parameters remained unchanged.

CONCLUSION

The natural mineral supplement, sierrasil alone and in combination with a cat's claw extract, improved joint health and function within 1-2 weeks of treatment but significant benefits over placebo were not sustained, possibly due to rescue medication masking. Sierrasil may offer an alternative therapy in subjects with joint pain and dysfunction.

Evidenzbasierte Bewertung der symptomatischen Therapie von Glucosamin

Meta-analyses can contribute to the field of evidence based medicine. In the systematic analyses so far published, the symptomatic efficacy of glucosamine was described to be moderate to large. The results of the individual clinical studies however do not support these findings unanimously. In the past couple of years, some new studies of high quality standard were published. This publication gives an overview and an evaluation of the current available studies for the symptomatic treatment of patients with gonarthrosis with glucosamine. It also compares the results of the individual studies with those of recent meta-analyses.

Glucosamine long-term treatment and the progression of knee osteoarthritis: systematic review of randomized controlled trials

OBJECTIVE

To investigate the structural and symptomatic efficacy and safety of glucosamine in knee osteoarthritis (OA).

DATA SOURCES

Clinical trials of glucosamine were identified through electronic searches (MEDLINE, EMBASE, BIOSIS, EMB review, the Cochrane Library) using the key words glucosamine, osteoarthritis, degenerative joint disease, degenerative arthritis, osteoarthrosis, gonarthrosis, knee, disease progression, and clinical trial. The bibliographic databases were searched from their respective inception dates to August 2004. We also hand-searched reference lists of relevant articles.

STUDY SELECTION AND DATA EXTRACTION

Studies were included if they were double-blind, randomized, controlled trials that evaluated oral glucosamine long-term treatment in knee OA; lasting at least one year; and reporting as outcome measures the symptom severity and disease progression as assessed by joint space narrowing. Two authors interpreted data independently. Disagreements were resolved through discussion.

DATA SYNTHESIS

Glucosamine sulfate was more effective than placebo in delaying structural progression in knee OA. The risk of disease progression was reduced by 54% (pooled RR 0.46; 95% CI 0.28 to 0.73; p = 0.0011). The number-needed-to-treat was 9 (95% CI 6 to 20). The pooled effect sizes for pain reduction and improvement in physical function were 0.41 (95% CI 0.21 to 0.60; p < 0.0001) and 0.46 (95% CI 0.27 to 0.66; p < 0.0001), respectively, in favor of glucosamine sulfate. Glucosamine sulfate caused no more adverse effects than placebo.

CONCLUSIONS

The available evidence suggests that glucosamine sulfate may be effective and safe in delaying the progression and improving the symptoms of knee OA. Due to the sparse data on structural efficacy and safety, further studies are warranted.

Glucosamine therapy for treating osteoarthritis

BACKGROUND

Osteoarthritis (OA) is the most common form of arthritis, and it is often associated with significant disability and an impaired quality of life.

OBJECTIVES

To review all randomized controlled trials (RCTs) evaluating the effectiveness and toxicity of glucosamine in OA.

SEARCH STRATEGY

We searched MEDLINE, PREMEDLINE, EMBASE, AMED, ACP Journal Club, DARE, CDSR, and the CCTR. We also wrote letters to content experts, and hand searched reference lists of identified RCTs and pertinent review articles. All searches were updated in January 2005.

SELECTION CRITERIA

Relevant studies met the following criteria: 1) RCTs evaluating the effectiveness and safety of glucosamine in OA, 2) Both placebo controlled and comparative studies were eligible, 3) Both single blinded and double blinded studies were eligible.

DATA COLLECTION AND ANALYSIS

Data abstraction was performed independently by two investigators and the results were compared for degree of agreement. Gotzsche's method and a validated tool (Jadad 1996) were used to score the quality of the RCTs. Continuous outcome measures were pooled using standardized mean differences (SMD) as the measure of effect size. Dichotomous outcome measures were pooled using relative risk ratios (RR).

MAIN RESULTS

Analysis restricted to eight studies with adequate allocation concealment failed to show benefit of glucosamine for pain and WOMAC function. Collectively, the 20 analyzed RCTs found glucosamine favoured placebo with a 28% (change from baseline) improvement in pain (SMD -0.61, 95% CI -0.95, -0.28) and a 21% (change from baseline) improvement in function using the Lequesne index (SMD -0.51 95% CI -0.96, -0.05). However, the results are not uniformly positive, and the reasons for this remain unexplained. WOMAC pain, function and stiffness outcomes did not reach statistical significance. In the 10 RCTs in which the Rotta preparation of glucosamine was compared to placebo, glucosamine was found to be superior for pain (SMD -1.31, 95% CI -1.99, -0.64) and function using the Lequesne index (SMD -0.51, 95% CI -0.96, -0.05). Pooled results for pain (SMD -0.15, 95% CI -0.35, 0.05) and function using the WOMAC index (SMD 0.03, 95% CI -0.18, 0.25) in those RCTs in which a non-Rotta preparation of glucosamine was compared to placebo did not reach statistical significance. In the four RCTs in which the Rotta preparation of glucosamine was compared to an NSAID, glucosamine was superior in two, and equivalent in two. Two RCTs using the Rotta preparation showed that glucosamine was able to slow radiological progression of OA of the knee over a three year period (SMD 0.24, 95% CI 0.04, 0.43). Glucosamine was as safe as placebo in terms of the number of subjects reporting adverse reactions (RR=0.97, 95% CI, 0.88, 1.08).

AUTHORS' CONCLUSIONS

This update includes 20 studies with 2570 patients. Pooled results from studies using a non-Rotta preparation or adequate allocation concealment failed to show benefit in pain and WOMAC function while those studies evaluating the Rotta preparation show that glucosamine was superior to placebo in the treatment of pain and functional impairment resulting from symptomatic OA. WOMAC outcomes of pain, stiffness and function did not show a superiority of glucosamine over placebo for both Rotta and non-Rotta preparations of glucosamine. Glucosamine was as safe as placebo.

Nutraceutical Therapies for Degenerative Joint Diseases: A Critical Review

There is growing recognition of the importance of nutritional factors in the maintenance of bone and joint health, and that nutritional imbalance combined with endocrine abnormalities may be involved in the pathogenesis of osteoarthritis (OA) and osteochondritis dissecans (OCD). Despite this, dietary programs have played a secondary role in the management of these connective tissue disorders. Articular cartilage is critically dependent upon the regular provision of nutrients (glucose and amino acids), vitamins (particularly vitamin C), and essential trace elements (zinc, magnesium, and copper). Therefore, dietary supplementation programs and nutraceuticals used in conjunction with non-steroidal, anti-inflammatory drugs (NSAIDs) may offer significant benefits to patients with joint disorders, such as OA and OCD. This article examines the available clinical evidence for the efficacy of nutraceuticals, antioxidant vitamin C, polyphenols, essential fatty acids, and mineral cofactors in the treatment of OA and related joint disorders in humans and veterinary species. This article also attempts to clarify the current state of knowledge. It also highlights the need for additional targeted research to elucidate the changes in nutritional status and potential alterations to the expression of plasma membrane transport systems in synovial structures in pathophysiological states, so that current therapy and future treatments may be better focused.

Glucosamine effects in humans: a review of effects on glucose metabolism, side effects, safety considerations and efficacy

Glucosamine is widely used to relieve symptoms from osteoarthritis. Its safety and effects on glucose metabolism are critically evaluated in this review. The LD50 of oral glucosamine in animals is approximately 8000 mg/kg with no adverse effects at 2700 mg/kg for 12 months. Because altered glucose metabolism can be associated with parenteral administration of large doses of glucosamine in animals and with high concentrations in in vitro studies, we critically evaluated the clinical importance of these effects. Oral administration of large doses of glucosamine in animals has no documented effects on glucose metabolism. In vitro studies demonstrating effects of glucosamine on glucose metabolism have used concentrations that are 100-200 times higher than tissue levels expected with oral glucosamine administration in humans. We reviewed clinical trial data for 3063 human subjects. Fasting plasma glucose values decreased slightly for subjects after oral glucosamine for approximately 66 weeks. There were no adverse effects of oral glucosamine administration on blood, urine or fecal parameters. Side effects were significantly less common with glucosamine than placebo or non-steroidal anti-inflammatory drugs (NSAID). In contrast to NSAID, no serious or fatal side effects have been reported for glucosamine. Our critical evaluation indicates that glucosamine is safe under current conditions of use and does not affect glucose metabolism.