Treating RA

Sunday June 29, 2008

Treating Rheumatoid Arthritis

By Dr YEAP SWAN SIM

RHEUMATOID arthritis (RA) is a chronic autoimmune arthritis that can lead to joint deformity and destruction if untreated. Therefore, it is important for both the public and the doctors to make the distinction between RA and the other types of arthritis, of which the most common is osteoarthritis (OA).

To complicate matters, there are many other types of arthritis, which have to be considered in the differential diagnosis of joint pain.

So, what is the difference between the two types of arthritis, RA and OA? And why is this so important?

Firstly, OA is a lot more common, affecting up to 20% of the population. In OA, there is basically a failure of repair of cartilage as one ages; thus the disease tends to affect the older population, and the rate of progression of the disease is slow, typically over 10 to 20 years.

RA is less common, affecting approximately 1% of the population in Western countries and about five in 1,000 people in Malaysia1.

In contrast to OA, RA tends to affect a younger population, classically starting between the ages of 30 and 55 years. Women are more likely to suffer from it compared to men, in a ratio of 3:12.

More importantly, in RA, the mechanism of disease is very different. There is production of abnormal antibodies and other hormones due to an activation of the immune system.

These abnormal antibodies are harmful to the joints and sometimes other parts of our bodies. They “attack” the joints, especially the lining of our joints called the “synovium”, leading the synovium to become thickened (“hypertrophied”), overproducing synovial fluid and thus causing swelling and pain in the joint (“inflammation”).

Long-term swelling in the joints due to this inflammatory fluid can lead to destruction of the cartilage inside the joint, and if further left unchecked, can lead to destruction of the bone (called “erosions”).

This destruction of joints/formation of erosions can happen quite quickly, as over 70% patients with RA can have bony erosions after only three years of disease3.

If left untreated, joint deformities can occur, with resultant difficulties in the activities of daily living.

In this day and age, we have treatments that should prevent such deformities from happening.

To diagnose RA, you will have to see your doctor. The diagnosis of RA is based on a combination of your signs and symptoms as well as some blood tests. There is no absolute one blood test that can confirm or exclude RA.

There is a blood test called the “rheumatoid factor” (RF), which is commonly done to see if you may have RA.

Unfortunately, the RF can be positive in many other diseases, not just RA, and conversely, about 30% of people with RA do not have a positive RF.

So, in some cases, your doctor may have to refer you to specialists called rheumatologists – doctors who specialise in treating arthritis, to check if you have RA.

Once the diagnosis of RA is made, treatment will have to be started, if the damage to the joints is to be prevented. As I have mentioned above, once the immune processes start, it is unlikely to stop on its own.

Therefore, it is unlikely that the disease will just “go away”. Even with our best treatments, we cannot cure RA, but we now have many medications that can alleviate symptoms, prevent progression of the disease and thus limit disability.

In the initial treatment of anyone with arthritis, painkillers such as non-steroidal anti-inflammatory drugs (NSAIDs) are given to relieve symptoms/pain. But they do not alter the course of the disease.

Therefore, the mainstay of the treatment of RA are drugs called “disease-modifying anti-rheumatic drugs” (DMARDs), which, as their name implies, can alter the immune system over-activity and therefore prevent the joint damage that can occur.

These drugs need to be taken regularly over many months and years to suppress inflammation and prevent the joint erosions. When joint erosions and thus joint destruction is prevented, the quality of life of patients with RA is improved.

Among the most commonly used DMARDs today are methotrexate, sulfasalazine, leflunomide and hydroxychloroquine, with methotrexate being the most widely prescribed DMARD4.

If a single drug is ineffective, combinations of DMARDs can be prescribed.

A newer, but much more expensive type of DMARD agents are called tumour necrosis factor-alpha (TNF-alpha) inhibitors. They inhibit a cytokine (a type of enzyme) called TNF, which is an important cytokine in the inflammatory pathway.

All these drugs, in varying degrees of effectiveness, will reduce inflammation, prevent joint erosions and thus reduce progression of RA.

Over the last 10 years, the introduction of new DMARDs has greatly revolutionised the treatment of RA.

Quite importantly, these agents have resulted in statistically significant and clinically meaningful improvements in physical function and health related quality of life of patients.

Work productivity studies are confirming that fewer patients stop working and more patients are reporting lesser impact of their disease on work as well as family and social activities5.

As it is now possible to detect and treat RA early, it is hoped that patients with RA, treated early and adequately, will be able to live normal, full and rewarding lives in the community.

References:

1. From Arthritis Foundation Malaysia, http://www.afm.org.my/info/rheumatoid_arthritis.php (accessed 5 June 2008)

2. Venables PJW, Maini RM. Clinical features of rheumatoid arthritis. http://www.uptodate.com/online version 16.1 (accessed 5 June 2008)

3. van der Heijde DM, van Leeuwen MA, van Riel PL et al. Biannual radiographic assessments of hands and feet in a three-year prospective followup of patients with early rheumatoid arthritis. Arthritis Rheum 1992;35:26-34

4. Pincus T, Aletaha D, Smolen J. Methrotrexate as the “anchor drug” for the treatment of early rheumatoid arthritis. Clin Exp Rhematol 2003;21(Supp 31):S179-S185

5. Strand V, Singh J A. Improved health-related quality of life with effective disease modifying antirheumatic drugs: Evidence from randomized controlled trials. Am J Manag Care. 2008;14(4):239-253

Dr Yeap Swan Sim is a consultant rheumatologist and president of the Malaysian Society of Rheumatology. This article is courtesy of sanofi-aventis.