This week's Lancet contains a three-part Series on arthritis. The first paper discusses issues and future directions around osteoarthritis, and is written by Professor Johannes W J Bijlsma, University Medical Centre Utrecht, Netherlands, and colleagues.
Osteoarthritis is thought to be the most prevalent chronic joint disease. The incidence of osteoarthritis is rising because of the ageing population and the epidemic of obesity. Osteoarthritis becomes more common with age, and after age 50 years more women than men are affected. The Rotterdam study of people aged 55 years or older reported that 67% of women and 55% of men had radiographic osteoarthritis* of the hand. In people older than 80 years, 53% of women and 33% of men had radiographic osteoarthritis of the knee.
Pain and loss of function are the main clinical features that lead to treatment, including non-pharmacological, pharmacological, and surgical approaches. Early osteoarthritis is dominated by pain and stiffness symptoms, thus interventions tend to focus on these elements. There is evidence of a positive effect of exercise. Weight reduction, though not easy, is also effective, especially in osteoarthritis of the knee. A range of drug treatments are also available, with pain moderated first by paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs). Weak opioids can be used in patients in whom NSAIDs do not work or are contraindicated. In patients with severe symptoms, joint replacement surgery is very cost effective.
The authors say that new discoveries about the pathophysiology of osteoarthritis mean that different types of the disease can now be better separated. They say: "Delineating the different clinical and structural phenotypes of the disease will improve understanding—of disease in patients with pain, trauma, or obese-dominated clinical phenotypes—and will also allow specific targeted treatment in those in whom structural changes in either cartilage, bone, or synovial tissue dominate the disease…A consensus on subgrouping osteoarthritis into such phenotypes will take time."
The authors give various examples of how different phenotypes can be targeted. They say: "A positive association between obesity and osteoarthritis has been reported for non-weight-bearing joints, such as those of the hands, and not only knee joints. These reports suggest that joint damage might also be caused by systemic factors such as adipose factors, the so-called adipokines, which might provide a metabolic link between obesity and osteoarhtritis, and which, in addition to weight loss, could become a specific therapeutic target."
They add: "Despite efforts over the past decades to develop markers of disease, still-imaging procedures and biochemical marker analyses need to be improved and possibly extended with more specific and sensitive methods to reliably describe disease processes, to diagnose the disease at an early stage, to classify patients according to their prognosis, and to follow the course of disease and treatment effectiveness."
Professor Johannes W J Bijlsma, University Medical Centre Utrecht, Netherlands. T) + 31 88 755 7357 E) j.w.j.bijlsma@umcutrecht.nl
Note to editors: * radiographic osteoarthritis is diagnosed through the presence of specific changes related to osteoarthritis on X-rays, eg, narrowing of joint width, formation of additional bone-spurs (osteophytes)
Journal
The Lancet