New ACR classification criteria for polymyalgia rheumatica

The American College of Rheumatology has released the first classification criteria for polymyalgia rheumatica - aimed at helping physicians identify patients with this condition, which occurs in persons aged 50 years or older who have recent onset of pain in the shoulders, neck and hips along with other inflammatory symptoms not explained by an alternate diagnosis.

Polymyalgia rheumatica is a relatively common cause of widespread aching and stiffness in older adults. It can be difficult to diagnose because it rarely causes swollen joints or other abnormalities on physical exam. In PMR, the aching is located primarily around the shoulders and hips, and the disease may occur with another rheumatic condition.

Until now, criteria to recognize polymyalgia rheumatica were not well established or tested. The pain and stiffness associated with PMR are common symptoms caused by other illnesses in older people. Additional factors that have contributed to low disease recognition include the lack of standardized tests to confirm the disease, minimal scientific research evaluating therapies, and the absence of genetic markers to identify disease risk.

The new criteria released by the ACR, in collaboration with The European League Against Rheumatism, will improve PMR recognition by defining the important disease features which are useful in classifying patient symptoms caused by this disease. The classification criteria will also provide a structure that will facilitate a better understanding of the disease and its course, and development of new therapies and clinical trials.

"The new criteria were developed by comparing patients with symptoms of PMR caused by a variety of conditions including rheumatoid arthritis and other conditions affecting shoulders and hips and patients with presumed PMR, and following them over a six month period. After six months, the investigators confirmed which patients had PMR, and what the characteristic disease features were, which separated the PMR patients from those with other conditions," says Eric Matteson, MD, MPH; ACR member and chief of rheumatology at the Mayo Clinic College of Medicine.

Dr. Matteson is one of the lead investigators who helped to develop the criteria and adds, "Fulfillment of these criteria will help to ensure that patients with the same disease are being evaluated, which will enhance our ability to study the disease, including performing outcomes studies and clinical trials. Still, there is much to be done to develop better tests for the diagnosis, assessment of disease activity and outcomes of PMR, including further assessment of the new criteria."

PMR is a common inflammatory rheumatic disease of the elderly affecting nearly 711,000 Americans. Under the new criteria, patients 50 years and older can be classified as having PMR if they meet all of the conditions below:

• Shoulder pain on both sides
• Morning stiffness that lasts at least 45 minutes
• High levels of inflammation measured by protein in blood and erythrocyte sedimentation
• Reported new hip pain
• Absence of swelling in the small joints of the hands and feet, and absence of positive blood tests for rheumatoid arthritis

The new classification criteria may also help to evaluate existing treatments for polymyalgia rheumatica. Currently, PMR is treated with low dose corticosteroid such as prednisone. The new criteria will help to assess the benefits of therapies in these patients by ensuring that the patients being evaluated actually all have the same condition.