It’s hard to turn on the news without hearing about weight loss drugs. Surveys suggest around 1 in 7 British people have either taken a medicine like Wegovy or Mounjaro – or know someone who has. That’s a big number.
There have been plenty of claims about the effectiveness of these drugs too. One recent study in America found that semaglutide (the drug that goes by the brand names Wegovy and Ozempic) can even reduce pain for people suffering with knee arthritis.
Could this be a major advancement for arthritis treatment? Let’s look at the detail…
What was the new study?
The research, published in the New England Journal of Medicine late last year, focused on 400 patients with knee osteoarthritis. All were overweight, mostly with body mass indexes (BMIs) over 30 (the threshold for obesity), and most were suffering moderate to severe arthritis pain. For 68 weeks, some of the patients were given weekly injections of semaglutide while others received a placebo. All 400 were given advice about dieting and exercise to reduce weight.
What did the study find?
At the end of the trial, the researchers found that patients who took semaglutide lost an average of around 14% of their bodyweight (about 30lb / 13kg) and reported a 42-point drop in their pain score (pain scores are measured out of 100). The placebo patients also reported a reduction in pain, but by 27.5 points. For clarity, we should note that the study was funded by Novo Nordisk, the Danish pharmaceutical company that manufactures and markets Wegovy and the diabetes drug Ozempic.
Why is weight a problem for arthritis?
Osteoarthritis pain occurs when we lose the smooth cartilage that stops joints from grinding against each other. The problem with obesity is that it puts joints under even greater strain. As we mentioned in this blog on exercise and arthritis, every pound we carry translates into roughly 4lbs of load-bearing pressure on our knees. Lose some of that weight and you can, potentially, reduce the strain on your joints in a big way.
How do weight loss drugs work?
Semaglutide mimics a hormone called glucagon-like peptide-1 (GLP-1 for short). GLP-1 is a naturally occurring hormone that our intestines release during a meal, to make us feel full. Taken as a weekly injection, semaglutide (and the similar drug tirzepatide, marketed as Mounjaro), achieve the same effect: they suppress appetite and, over time, can help people lose weight.
Is this good news for arthritis sufferers?
On the face of it, yes. Thirty pounds is a significant figure – and the pain score reduction is perhaps even more impressive. It suggests the drugs might also benefit another important group of knee patients: those who are struggling to be considered for knee replacement surgery. Since a very high BMI can complicate or limit access to this procedure, weight loss using Wegovy potentially opens the door to an operation that wasn’t there before – or that might otherwise have involved weight loss surgery. If nothing else, the trial reinforces the point that reducing weight is a good thing for arthritis joint pain.
Are there any reasons to be cautious?
As with any new medicine, there are some caveats. One is that, for some patients, the side effects of weight loss drugs could outweigh the benefits. Another important question is: how long would you expect to take this medication for, and what will happen to your weight when you come off it? The NHS currently says semaglutide for obesity should be taken for “a maximum of two years”. So, while losing weight has powerful implications for pain-relief and knee surgery, it needs to be associated with the kind of lifestyle changes that will endure over the long term. Overall, then, these findings are encouraging – but we need to keep the bigger picture about arthritis, joint pain and lifestyle in view.
