What Is the Rheumatoid Arthritis Severity Scale?

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  • Rheumatoid Arthritis Overview

    Rheumatoid Arthritis Overview

    Rheumatoid arthritis (RA) is a chronic and progressive disease with a profound physical and mental impact on the patient. Understanding a patient’s severity of the disease is an important factor in helping doctors and patients evaluate if treatments are working, what treatments to consider next, and how to prepare for a patient’s future. The Rheumatoid Arthritis Severity Scale (RASS) was developed in 2002 by a group of doctors seeking a subjective measure of disease growth. Learn what the RASS is and how doctors use it to help patients with RA.

  • Diagnosis


    Much about RA is unknown including why it starts, how best to treat it, and why it is more severe in some patients. It is also difficult to diagnose. Doctors rely on the patient’s experience, a physical examination, and blood tests, all of which may not always be completely accurate. RA causes the lining of an individual’s joints to swell. RA hurts those joints and the surrounding muscles, but many patients cannot distinguish between joint pain and muscle pain. This makes diagnosis and assessment difficult.  

  • Problems of Assessment

    Problems of Assessment

    After diagnosis, the level and progression of the disease need to be tracked. Prior to the RASS, doctors combine a physical examination with factors reported by the patient, such as pain level, to estimate RA severity.  Doctors also use the Health Assessment Questionnaire (HAQ) in which patients rate their own estimated levels of pain. The challenge is that patients range in their individual opinion of their own physical and emotional well-being. This assessment also is complicated by the close relationship between pain and depression.

  • The Role of Depression in Assessment

    The Role of Depression in Assessment

    Depression is a significant component of RA. But there are problems using it as a guide to disease growth. Such challenges include:

    • some patients may be more depressed than others
    • a patient may feel particularly depressed at the time of examination time
    • some patients are reluctant to admit to depression

    While depression is a meaningful element of RA, measuring it is not helpful for disease assessment. The RASS is completed by a doctor and based on the visible symptoms of the disease and the patient, not a patient’s individual emotional assessment.

  • Types of RA

    Types of RA

    There are three types of RA. It’s important to know what type you have to get an accurate assessment of development.

    • Monocylic: symptoms last for two to five years, and then go away permanently
    • Polycyclic: symptoms never go away once they have begun, but sometimes become less problematic
    • Progressive: symptoms regularly increase and movement is increasingly difficult
  • What the RASS Measures

    What the RASS Measures

    The RASS measures three areas: disease activity, functional impairment and physical damage. All three areas are assessed using a range of 1—100, with a score of 1 meaning the doctor evaluates no evidence of the condition with 100 as the maximum level of progression. Doctors look for disease activity like joint swelling during a physical exam. Next, a doctor will check functional impairment with range of motion exercises. The physical damage component of the RASS looks at how much permanent damage RA has affected the body.

  • Disease Activity Score

    Disease Activity Score

    This is perhaps the most important of the three scores for a patient to be familiar with. The Disease Activity Score determines whether RA is in remission or whether there is low, moderate, or severe disease activity. Knowing the Disease Activity Score in a patient with polycyclic or progressive RA helps both the doctor and patient assess if treatments are working or if they need to be changed.

  • Functional Impairment

    Functional Impairment

    Following the Disease Activity Score, the RASS looks at Signals of Functional Impairment, SOFI. The doctor performs SOFI by looking at how far and how well the patient is able to move their hands, arms (upper SOFI), and legs (lower SOFI). The doctor also looks at how quickly the patient can walk a set distance. The patient uses assistance walking, such as a cane, if necessary.

  • Physical Damage

    Physical Damage

    The final part of the RASS looks at how much damage the disease has caused. It is completed with an X-ray or other imaging tool such as an MRI or a CT scan. For the physical damage component, the doctor looks for scarring and/or destruction or deformity of the joints affected by RA and of the bones around them.

  • Understanding and Treating RA

    Understanding and Treating RA

    It is difficult to diagnose RA because disease symptoms are similar to many other conditions. Once diagnosis is determined, the severity of the disease needs to be determined to begin treatment. An ongoing understanding of disease growth is critical to a patient’s health and well-being. The RASS helps doctors and patients pinpoint the severity of the disease and the effectiveness of treatment.