Knee osteoarthritis

Knee osteoarthritis is a debilitating, painful joint disorder largely treated by lifestyle changes and anti-inflammatory drugs. A combination of chondroitin sulfate (CS) and glucosamine sulfate (GS) was shown to be ineffective compared to placebo treatment in a recent study.


Treatment of knee osteoarthritis (OA) is difficult due to the disorder’s chronic nature. The joint progressively deteriorates, leading to pain, a decrease in quality of life, and in severe cases, joint instability. Most clinicians currently advise lifestyle changes such as weight loss and muscle strengthening, in addition to prescribing anti-inflammatory and pain relieving drugs. In most cases, if the condition becomes severe, joint replacement remains the best option.

One class of pain-relieving drugs is the symptomatic slow acting drugs in OA (SySADOAs). They are specifically used in the treatment of osteoarthritis and are intended to relieve the intensity of osteoarthritis-related pain. SySADOAs are a source of great controversy due to questionable study results despite their common usage. Contradictory results have arisen, with differences in chemical formulation, allocation, and quality of drugs and potential sponsor bias. With this in mind, researchers set out to assess the efficacy of a specific SySADOA treatment in comparison with a placebo.

In this study published in Arthritis & Rheumatology, Roman-Blas et al. assessed the merits of chondroitin sulfate (CS) and glucosamine sulfate (GS) combination therapy compared to placebo after 6 months in symptomatic knee OA patients. The placebo group was included due to the high placebo effect in past OA clinical research. Patients with symptomatic (painful) knee OA were randomly assigned to the treatment or placebo group. To qualify, patients had to have grade 2 or grade 3 knee OA as classified by radiography, moderate to severe knee pain and could not have any coexisting conditions that may have prevented completion of the study. Patients followed up with the clinic at 4, 12 and 24 weeks after beginning the study, and the efficacies of the treatments were determined by changes in several pain management surveys. A Data and Safety Monitoring Board (DSMB) was included to both ensure that the minimum number of patients received placebo treatment to obtain conclusive results and to confirm an accurate, bias-free study.

The results show that CS and GS combination therapy did not provide any benefit when compared with placebo in treating symptomatic knee OA. In fact, the placebo group had greater pain alleviation according to the pain management surveys, though the difference was insignificant. While the potential for sponsor bias was found in previous studies, the inclusion of a DSMB helped prevent unnecessary placebo treatment and ensured accurate analysis, as the DSMB completed separate analysis from the researchers. Also, this study used pharmaceutical grade CS and GS, while pharmaceutical quality has been questioned in previous SySADOA studies. Some limitations of the study include a small, but statistically relevant sample size, and a higher number of study dropouts due to adverse effects in the CS/GS group, which may have affected pain level reporting. Despite these limitations, the study found that CS/GS combination therapy was not superior to placebo treatment in reducing symptoms of knee OA.


Written By: Wesley Tin, BMSc

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