Simple Fibromyalgia Assessment Screening Tool (FAST) indices may facilitate the diagnosis of fibromyalgia (FM) in the routine care of patients with other rheumatic diseases, according to study results published in The Journal of Rheumatology.
Although FM is common in patients with rheumatic diseases, there is no diagnostic marker for the disease. The American College of Rheumatology developed classification criteria for FM, but these are not typically used in routine clinical care other than by subspecialists, which may result in FM being misdiagnosed or not diagnosed.
The goal of the study was to identify indices that may provide clues to the presence of FM in patients with other rheumatic diseases based on multidimensional health assessment questionnaire (MDHAQ) scores. FAST composite cumulative indices were developed from MDHAQ candidate measures. The FAST3 index consist of a cumulative score of the symptom checklist, painful joint count, and a visual analog scale (VAS) for pain (FAST3-P), or for fatigue (FAST3-F). The FAST4 index consists of a cumulative score of the symptom checklist, painful joint count, pain VAS, and fatigue VAS.
The study included 148 patients age >18 years who visited Liverpool Hospital in the United Kingdom between February 2013 and August 2016 and had a primary diagnosis of any rheumatic condition except FM. Participants were asked to complete both the MDHAQ and 2011 FM criteria questionnaire. The cohort included 55 patients (37%) with rheumatoid arthritis, 21 (14%) with osteoarthritis (OA), 14 (10%) with psoriatic arthritis, and 58 (39%) with other rheumatologic diagnoses.
Diagnosis of FM according to 2011 criteria was evident in 24% of patients with rheumatoid arthritis, 38% with osteoarthritis, and 21% with psoriatic arthritis. A clinical diagnosis of FM was established in 22%, 38%, and 29%, of participants with rheumatoid arthritis, osteoarthritis, and psoriatic arthritis, respectively.
In patients with vs without an FM diagnosis according to the 2011 criteria, all MDHAQ scores were lower. The highest area under the curve in receiver-operating-curve analyses vs 2011 FM criteria were observed for the MDHAQ symptom checklist, self-report painful joint count, pain VAS, and fatigue VAS. The optimal cutoff points were ≥16 for the symptom checklist, ≥16 for the self-reported painful joint count, and ≥6 for both pain and fatigue VAS.
A FAST3-P score ≥2 was found to correctly classify 90.9% of patients as having FM, against the 2011 FM Criteria (sensitivity, 81.5%; specificity, 93.3%). A FAST3-F score ≥2 correctly classified 89.4% of patients against the 2011 FM Criteria (sensitivity, 77.8%; specificity, 92.4%). A FAST4 score ≥3 correctly classified 91.7% of patients against the 2011 FM Criteria (sensitivity, 70.4%; specificity, 97.1%).
The agreement on a clinical diagnosis of FM was 81.1% for FAST3-P, 85.6% for FAST3-F, and 58.8% for FAST4.
Study limitations include its cross-sectional design, possible fluctuations in symptoms over time, dichotomous criteria to evaluate the presence/absence of FM, and the fact that the study did not take into account the 2016 modification of the FM criteria.
“We have developed simple FAST cumulative, composite indices that provide clues to the presence of FM in patients with primary diagnoses of other rheumatic diseases. These indices are based entirely on the patient self-report MDHAQ questionnaire, which is used in routine care in the setting of the research and other rheumatology settings, and does not require a disease-specific FM questionnaire,” concluded the researchers.
Gibson KA, Castrejon I, Descallar J, Pincus T. Fibromyalgia Assessment Screening Tool (FAST): clues to fibromyalgia on a multidimensional health assessment questionnaire (MDHAQ) for routine care [published online, September 1, 2019]. J Rheumatol. doi:10.3899/jrheum.190277