***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Glucosamine and chondroitin sulfate are used to treat osteoarthritis . The multicenter , double-blind , placebo- and celecoxib-controlled Glucosamine/chondroitin Arthritis Intervention Trial ( GAIT ) evaluated their efficacy and safety as a treatment for knee pain from osteoarthritis . METHODS We r and omly assigned 1583 patients with symptomatic knee osteoarthritis to receive 1500 mg of glucosamine daily , 1200 mg of chondroitin sulfate daily , both glucosamine and chondroitin sulfate , 200 mg of celecoxib daily , or placebo for 24 weeks . Up to 4000 mg of acetaminophen daily was allowed as rescue analgesia . Assignment was stratified according to the severity of knee pain ( mild [ N=1229 ] vs. moderate to severe [ N=354 ] ) . The primary outcome measure was a 20 percent decrease in knee pain from baseline to week 24 . RESULTS The mean age of the patients was 59 years , and 64 percent were women . Overall , glucosamine and chondroitin sulfate were not significantly better than placebo in reducing knee pain by 20 percent . As compared with the rate of response to placebo ( 60.1 percent ) , the rate of response to glucosamine was 3.9 percentage points higher ( P=0.30 ) , the rate of response to chondroitin sulfate was 5.3 percentage points higher ( P=0.17 ) , and the rate of response to combined treatment was 6.5 percentage points higher ( P=0.09 ) . The rate of response in the celecoxib control group was 10.0 percentage points higher than that in the placebo control group ( P=0.008 ) . For patients with moderate-to-severe pain at baseline , the rate of response was significantly higher with combined therapy than with placebo ( 79.2 percent vs. 54.3 percent , P=0.002 ) . Adverse events were mild , infrequent , and evenly distributed among the groups . CONCLUSIONS Glucosamine and chondroitin sulfate alone or in combination did not reduce pain effectively in the overall group of patients with osteoarthritis of the knee . Exploratory analyses suggest that the combination of glucosamine and chondroitin sulfate may be effective in the subgroup of patients with moderate-to-severe knee pain . ( Clinical Trials.gov number , NCT00032890 . ) Patients with osteoarthritis ( OA ) of the knee were treated with chondroitin sulfate ( CS , Condrosulf , IBSA , Lugano , CH ) in a r and omized , double-blind , placebo-controlled study , performed in two centres . The efficacy and tolerability of oral CS capsules 2 x 400 mg/day vs placebo was assessed in a 6-month study period . Patients with idiopathic or clinical ly symptomatic knee OA , with Kellgren and Lawrence radiological scores I-III , were included in this trial . Clinical controls were performed at months 0 , 1 , 3 and 6 . Eighty patients completed the 6-month treatment period . Lequesne 's Index and spontaneous joint pain ( VAS ) decreased constantly in the CS group ; on the contrary , slight variations of the scores were reported in the placebo group . The walking time , defined as the minimum time to perform a 20-meter walk , showed a statistically significant constant reduction only in the CS group . ANOVA with repeated measures showed a statistically significant difference in favor of the CS group for these three parameters . During the study , patients belonging to the placebo group reported a higher paracetamol consumption , but this consumption was not statistically different between the two treatment groups . Efficacy judgements were significant in favor of the CS group . Both treatments were very well tolerated . All these results strongly suggest that chondroitin sulfate acts as a symptomatic slow-acting drug in knee OA The aim of this study was to assess the clinical , radiological and biological efficacy and tolerability of the SYSADOA , chondroitin 4- and 6-sulfate ( CS , Condrosulf , IBSA , Lugano , Switzerl and ) , in patients suffering from knee osteoarthritis . This was a 1-year , r and omized , double-blind , controlled pilot study which included 42 patients of both sexes , aged 35 - 78 years with symptomatic knee OA . Patients were treated orally with 800 mg chondroitin sulfate ( CS ) per day or with a placebo ( PBO ) administered in identical sachets . The main outcome criteria were the degree of spontaneous joint pain and the overall mobility capacity . Secondary outcome criteria included the actual joint space measurement and the levels of biochemical markers of bone and joint metabolism . This limited study confirmed that chondroitin sulfate was well-tolerated and both significantly reduced pain and increased overall mobility capacity . Treatment with CS was also associated in a limited group of patients with a stabilization of the medial femoro-tibial joint width , measured with a digitized automatic image analyzer , whereas joint space narrowing did occur in placebo-treated patients . In addition , the metabolism of bone and joint assessed by various biochemical markers also stabilized in the CS patients whereas it was still abnormal in the PBO patients . These results confirm that oral chondroitin 4- and 6-sulfate is an effective and safe symptomatic slow-acting drug for the treatment of knee OA . In addition , CS might be able to stabilize the joint space width and to modulate bone and joint metabolism . This is the first preliminary demonstration that a SYSADOA might influence the natural course of OA in humans OBJECTIVE To determine whether chondroitin sulfate ( CS ) is effective in inhibiting cartilage loss in knee osteoarthritis ( OA ) . METHODS In this r and omized , double-blind , placebo-controlled trial , 300 patients with knee OA were recruited from an outpatient clinic , from private practice s , and through advertisements . Study patients were r and omly assigned to receive either 800 mg CS or placebo once daily for 2 years . The primary outcome was joint space loss over 2 years as assessed by a posteroanterior radiograph of the knee in flexion ; secondary outcomes included pain and function . RESULTS Of 341 patients screened , 300 entered the study and were included in the intent-to-treat analysis . The 150 patients receiving placebo had progressive joint space narrowing , with a mean + /- SD joint space loss of 0.14 + /- 0.61 mm after 2 years ( P = 0.001 compared with baseline ) . In contrast , there was no change in mean joint space width for the 150 patients receiving CS ( 0.00 + /- 0.53 mm ; P not significant compared with baseline ) . Similar results were found for minimum joint space narrowing . The differences in loss of joint space between the two groups were significant for mean joint space width ( 0.14 + /- 0.57 mm ; P = 0.04 ) and for minimum joint space width ( 0.12 + /- 0.52 mm ; P = 0.05 ) . CS was well tolerated , with no significant differences in rates of adverse events between the two groups . CONCLUSION While there was no significant symptomatic effect in this study , long-term treatment with CS may retard radiographic progression in patients with OA of the knee . However , the clinical relevance of the observed structural results has to be further evaluated , and further studies are needed to confirm the structural effects of CS Chondroitin sulfate ( Condrosulf ) was characterized for structure , physiochemical properties and purity . This glycosaminoglycan has a relative molecular mass of about 14,000 , a sulfate-to-carboxyl ratio of 0.95 due to the high percentage of monosulfated disaccharides ( 38 % 6-monosulfate and 55 % 4-monosulfate ) and a low amount of disulfated disaccharides ( 1.1 % ) inside the polysaccharide chains . No other glycosaminoglycans were detected in the preparation . Chondroitin sulfate was labelled by reduction with sodium 3H-borohydride and administered by oral route in the rat and dog . More than 70 % of radioactivity was absorbed and found in urine and tissues . The plasma radioactivity was fractionated by size-exclusion chromatography in three fractions : radioactivity associated with high , intermediate and low molecular mass compounds . The peak value of the concentration of high molecular mass radioactivity compounds in plasma was reached after 1.6 and 2.1 h for the rat and dog , respectively . After 36 h the high molecular mass radioactivity compounds were still present in plasma of dog and rat . After 24 h radioactivity was higher in the intestine , liver , kidneys , synovial fluid and cartilage than in other tissues . Condroitin sulfate was orally administered to man ( healthy volunteer ) in a single daily dose of 0.8 g and in two daily doses of 0.4 g. The results showed that both forms of administration determined a significant increase of plasma concentration of chondroitin sulfate as compared with predose value over a full 24 h period . Elimination constant values and tmax ( of the first administration in the case of fractionated dose ) were almost the same for the two administrations . ( ABSTRACT TRUNCATED AT 250 WORDS One hundred twenty patients with osteoarthritis of the knees and hips were entered into a r and omized , placebo-controlled , double-blind trial design ed to evaluate the effectiveness of chondroitin sulfate ( Structum ) . The three-month treatment phase was followed by a two-month treatment-free phase to allow evaluation of carry-over effects . The main endpoint was use of nonsteroidal antiinflammatory drugs ( expressed as mg of diclofenac equivalent ) . At completion of the three-month treatment phase , patients taking chondroitin sulfate ( 4 capsules/day ) were using significantly less  NSAIDs ;  this decrease persisted throughout the two-month treatment-free follow-up phase . The other parameters studied including visual analog scale assessment of pain , the Lequesne pain-function index , and overall patient and physician assessment s , all showed a similar significant tendency . Tolerance was outst and ing and no patients required premature withdrawal . These findings indicate that chondroitin sulfate is useful for the treatment of osteoarthritis , both as an agent slowly effective against symptoms and to reduce the need for NSAIDs .  The carry-over effect of the drug suggests that intermittent administration may be appropriate AIM To study clinical effectiveness and tolerance of structum in patients with osteoarthrosis ( OA ) of the knee joints ( KJ ) and hip joints ( HJ ) in a multicenter open r and omised trial . MATERIAL AND METHODS A 6-month trial of effectiveness and tolerance of structum has been performed in 9 medical centers and included out patients ( males and females ) with KJ OA or HJ OA satisfying the OA diagnostic criteria of the American Rheumatology College , having x-ray stage I-III according to Kellgren-Lawrence with manifest pain , a total functional Leken index from 4 to 11 , regular intake of non-steroid antiinflammatory drugs ( NAID ) for 30 days in the last 3 months . Consent was obtained from each patient . 192 patients received structum , 363 matched patients served control . Structum was given per os for 3 weeks in a dose of 1.5 g/day then in a dose 1.0 g/day up to 6 months . The patients continued on NAID . The patients ' examination was performed in the beginning of the study , at its months 3 and 6 . RESULTS Leken index in HJ and KJ OA significantly fell after 3 months of structum treatment . Up to month 6 it fell still further ( p < 0.05 ) . After 6 months of treatment pain syndrome relieved both at rest and movement , pain at rest disappeared fully in 57 % of NJ OA patients and 46 % of HJ OA patients , for movement pain it was 17 and 13 % , respectively . During the treatment  NAID intake was less required in both groups ( p < 0.05 ) while 55 % of patients in both groups could discontinue NAID after 6 months of the treatment . Tolerance of the drug was rather good , side effects were mild . CONCLUSION Structum ( chondroitin sulphate ) is an effective drug for treatment of KJ and HJ OA : it relieves pain , preserves and improves articular function , allows to reduce or discontinue NAID , is well tolerated To evaluate the efficacy and tolerance of galactosaminoglycuronoglycan sulfate ( Matrix vials ) in the therapy of tibiofibular arthritis of the knee , forty patients suffering from this illness at radiological stages 1 and 2 undergoing concomitant therapy with NSAIDS , were r and omized into two groups of twenty . The treatment group received the drug under study and the control group received placebo . Treatment was carried out in double blind . The therapy protocol comprised 25 intramuscular injections ( one injection twice a week ) . This cycle was repeated for 6 months , for a total of 50 injections . The patients were visited on days 0 , 90 , 180 , 240 , 330 and 360 . At each visit the following symptoms were evaluated : spontaneous pain , pain on loading , on passive movement and on pressure ; changes in NSAIDS posology were also recorded ; lastly any possible side effects were noted . Analysis of results has shown a statistically significant higher therapeutic effect on treatment with Matrix for all the symptoms taken into consideration . No important side effects were noted , either 
    Output:
    
Recent high- quality trials showed chondroitin had minimal or no effect on joint pain .
Few adverse events were reported .
Implication Chondroitin probably does not prevent or reduce joint pain in people with osteoarthritis .