The American College of Rheumatology Updated Its Approved Disease Activity Measures for Rheumatoid Arthritis — Here’s What That Means

If you want to know how much you weigh, all you have to do is step on a scale. Curious about your blood pressure? Strap on a monitor and find out. Figuring out how active your rheumatoid arthritis (RA) is, however, is not so straightforward.

While RA patients certainly know how they feel on any given day and can usually identify when they’re in a full-blown flare, they don’t have a complete picture of what’s going on inside their bodies. In order to accurately determine whether a patient’s current disease activity is low, moderate, high, or severe — and to alter treatment if necessary — doctors rely on a combination of physical exams, blood tests for inflammatory markers, and imaging tests (like X-rays and MRIs), in addition to patient-reported symptoms. Then they combine some or all of this info together and turn it into a “composite disease activity measure.”

While that sounds simple enough, there are at least 63 different types of composite disease assessment tools for rheumatoid arthritis.

In 2015, when the American College of Rheumatology (ACR) introduced guidelines that advised clinicians to employ a “treat-to-target” strategy, the organization acknowledged that you can’t know if you’re hitting your target (usually remission or low disease activity) unless you have an accurate way to assess disease activity.

At the time, the ACR recommended six disease activity scores for clinicians to choose from:

• Clinical Disease Activity Index (CDAI)
• Disease Activity Score in 28 joints (DAS28)
• Patient Activity Scale (PAS)
• Patient Activity Scale II (PAS‐II)
• Routine Assessment of Patient Index Data 3 (RAPID3)
• Simplified Disease Activity Index (SDAI)

Now five years have passed, and in that time new ways to measure disease activity have been introduced and additional research on the validity of existing tools has been published. In recognition of these developments, the ACR assembled a working group to study the most recent and best evidence so it could update its 2015 guidelines as they pertain to disease assessment.

The team ended up analyzing 46 different disease activity measures and selected five that are considered preferred tools, plus an additional seven that meet the “minimum standard for regular use.”

The goal of the recommendations is to help doctors make an informed decision about which RA disease activity measures to use in everyday practice.

This update appears in the November 2019 issue of the journal Arthritis Care & Research.

The 2019 document doesn’t make sweeping changes, as the preferred tools are largely the same ones that were recommended back in 2015. But ACR did strike PAS from the preferred list and also added a relatively new multi-biomarker disease assessment (MBDA), also known as Vectra, to the group of tools deemed acceptable.

Preferred RA Disease Activity Measures for Regular Office Visits

Clinical Disease Activity Index (CDAI)

This incorporates information from the patient and provider based on physical exam, including an assessment of tenderness and swelling in 28 joints. It also includes Patient Global Assessment of Disease Activity (how well you think you’re doing on a scale of 0-10) and Provider Global Assessment of Disease Activity (rheumatologist rates patient status on the same scale).

Disease Activity Scale-28 (DAS28-ESR/CRP)

This incorporates tender/swollen joint count of the same 28 joints included in CDAI, plus the Patient Global Health Assessment (measured on a scale of 0-100) and the results of a biomarker blood test (ESR or CRP).

Patient Activity Scale II (PAS-II)

More concise than an older version (PAS), the PAS-II includes a series of questions designed to assess difficulty with everyday tasks, both in general and within the past week, plus a pain scale test (patients are asked to rate their pain on a scale of 0-10).

Routine Assessment of Patient Index Data 3 (RAPID3)

This combines three measures of function, pain, and patient self-assessment of well-being. A short questionnaire asks patients to rate their level of difficulty performing everyday tasks, as well as their mental state (depression and/or anxiety), ability to sleep well, participation in social activities, and pain level.

Simple Disease Activity Index (SDAI)

A combination of 28-joint tender and swollen joint count, CRP blood test results, Patient Global Assessment of Disease Activity, and Provider’s Global Assessment of Disease Activity.

Which Tool Should Your Doctor Use for Assessing Your RA?

That’s really up to them.

“The purpose of these recommendations was to assist clinicians in the care of RA patients by identifying RA disease activity measures and evaluating their performance and feasibility for regular use,” the authors wrote. “These recommendations are not meant to dictate the specific RA disease activity measure a clinician utilizes. The working group recognizes that feasibility varies based on practice and provider.”

“Furthermore, providers may have experience with and be comfortable with specific RA disease activity measures. Therefore, we aimed to identify not only preferred RA disease activity measures, but also RA disease activity measures that met a minimum standard by categorizing into disease activity states, possessing adequate psychometric properties, and being feasible for regular clinical use.”

The seven additional assessment tools met this minimum standard:

• Disease Activity Score (DAS)
• Patient Derived DAS28
• Hospital Universitario La Princesa Index (HUPI)
• Multi‐Biomarker Disease Activity Score (MBDA)
• Rheumatoid Arthritis Disease Activity Index (RADAI)
• Rheumatoid Arthritis Disease Activity Index 5 (RADAI‐5)
• Routine Assessment of Patient Index Data 5 (RAPID5)

The inclusion of the MBDA is particularly notable both because it is relatively new and because it is a single blood test that measures 12 biomarkers at once.

Leonard H. Calabrese, DO, chief medical editor of Healio Rheumatology and a consultant to the company that created the MBDA (Vectra), said in a Healio editorial that including Vectra in the updated guidelines is a major and important change. Calabrese said that he agreed with ACR’s decision to leave MBDA off the list of preferred assessment tools that should be used at every doctor visit, but that it can be very helpful in certain instances.

“In my opinion, its value as a disease activity measurement is to provide a robust estimation of prognosis, and especially as a tool to help sort out discordance where patients and providers differ in their global assessments,” he wrote, noting that such discrepancies can occur in as many as one in three visits. Dr. Calabrese cautioned against doctors over-relying on “gut feelings” because they can lead to risks of over-treatment.

For more information on how you and your doctor can monitor your RA disease activity, check out our new resource, A Patient’s Guide to Understanding Rheumatoid Arthritis Testing & Monitoring.

Use Our ArthritisPower App to Track Your Symptoms, Disease Activity, and More

Join CreakyJoints’ patient-centered research registry to track your symptoms, disease activity, and medications — and share with your doctor. Learn more and sign up here.

Keep Reading

• Understanding Your Vectra Score and What It Says About Your RA
• Switching Your Arthritis Medication: 7 Signs It’s Time to Consider It
• The 4 Stages of Rheumatoid Arthritis Progression

Myriad Genetics, Inc., which makes the MBDA (Vectra) test, is a corporate sponsor of the Global Healthy Living Foundation.