New Indexes Based on Self-reported Questionnaires May Be Useful to Identify Fibromyalgia

New Indexes Based on Self-reported Questionnaires May Be Useful to Identify Fibromyalgia

Investigators created new indexes based on patients’ self-reported questionnaires that may be useful identifying fibromyalgia in individuals who have been diagnosed with other rheumatic diseases.

The study, “Fibromyalgia Assessment Screening Tool (FAST): clues to fibromyalgia on a multidimensional health assessment questionnaire (MDHAQ) for routine care,” was published recently in The Journal of Rheumatology.

Fibromyalgia is a complex condition characterized by widespread muscle pain, fatigue, sleep disturbance, and memory and mood issues. As with most rheumatic diseases, there is no “gold standard” diagnostic marker that can be used to accurately identify the presence of fibromyalgia.

In 1990, the American College of Rheumatology (ACR) defined the first diagnostic criteria for fibromyalgia, but this set of guidelines was considered by many as highly subjective, time-consuming, and noninclusive. In an attempt to improve this system, the ACR released new diagnostic criteria in 2010 designed specifically to facilitate their application in clinical practice.

In 2011, a modification was added to the diagnostic criteria so that it included the patient self-report widespread pain index and symptom severity scale questionnaire.

“FM [fibromyalgia] criteria are not used in most routine clinical care, other than by sub-specialists. It is not feasible to ask patients with different diagnoses to complete different patient self-report questionnaires in busy clinical settings. As a consequence, clinicians may both fail to identify or incorrectly identify patients as having FM,” the investigators wrote.

In this study, researchers from the University of New South Wales in Australia and their collaborators set out to create a new set of indexes to be used in routine clinical practice to facilitate the identification of fibromyalgia in individuals who had been diagnosed with other types of rheumatic diseases.

The new indexes, called the fibromyalgia assessment screening tool (FAST), were based on three (FAST3) or four (FAST4) different measures of the the self-reported multidimensional health assessment questionnaire (MDHAQ) scores, which has been found to be informative in most rheumatic diseases.

All patients participating in the study were asked to complete an MDHAQ at each visit. The percentage of patients who met the 2011 ACR diagnostic criteria for fibromyalgia, or who already had been diagnosed with the disorder, also was calculated.

The individual MDHAQ patient scores were compared to the 2011 ACR diagnostic criteria. Statistical analyses were used to determine the best cut-points to identify fibromyalgia with the highest possible sensitivity and specificity.

The study enrolled 148 patients with rheumatic diseases, including 55 (37%) with rheumatoid arthirtis (RA), 21 (14%) with osteoarthritis (OA), 14 with psoriatic arthritis (PsA) (10%), and the remaining 58 (39%) with other rheumatic disorders.

Of the 148 patients who participated in the study, 29 (20%) met the 2011 ACR diagnostic criteria, 31 (21%) had been diagnosed with fibromyalgia, 18 (12%) met the diagnostic criteria and had received a clinical diagnosis of fibromyalgia, and 106 (72%) did not meet the criteria and had never been diagnosed with the disorder.

Statistical analyses revealed the MDHAQ symptom checklist, self-report painful joint count, pain visual analogue scale (VAS), and fatigue VAS, were the measures that better reflected the findings of the 2011 ACR diagnostic criteria and allowed accurate identification of fibromyalgia.

More specifically, they found that patients who had at least 16 of the 60 symptoms listed on the symptom checklist, or at least 16 of the 48 self-report painful joint count, or scored more than six points on VAS or fatigue VAS, were likely to have fibromyalgia.

When they combined all four MDHAQ measures (FAST4) with the respective cut-points, or used different combinations of three of those measures (FAST3), they correctly identified 76.2%–82.4% of patients who met the 2011 ACR diagnostic criteria.

“FAST3 provides greater sensitivity but lower specificity than FAST4 for clues to FM; it may be desirable to use a FAST3-P index as the first screening tool for greater sensitivity, and check positive patients according to FAST4 for greater specificity,” the researchers said.

“The FAST indices can be incorporated easily into routine care and may assist clinicians to identify patients with FM in the context of other comorbid rheumatic diseases. They remain a tool to support clinical [judgment] and are not a substitute for appropriate and thorough clinical history, physical examination and comprehensive patient assessment for a diagnosis of FM,” they said.