Results of a longitudinal study have confirmed that the recently established EULAR definition of arthralgia suspicious for progression to rheumatoid arthritis can help to distinguish patients who are at highest risk for progression from those who do not progress to RA.
Patients clinically suspected of arthralgia who met the definition for arthralgia suspicious for progression to RA displayed an increased risk for arthritis development, compared with patients who did not meet the EULAR definition (hazard ratio, 2.1; 95% confidence interval, 0.9-4.7). The approach had a sensitivity of 83% and positive predictive value of 30%, study head Annette van der Helm–van Mil, MD, reported at the European Congress of Rheumatology in Madrid.
Dr. Annette van der Helm–van Mil
The findings should help investigators looking at early arthritis progression to design better clinical trials by enabling more homogeneous populations of patients to be included, said Dr. van der Helm–van Mil, professor of rheumatology at Leiden University Medical Center and at Erasmus Medical Center in Rotterdam, both in the Netherlands.
“Previous data have shown that rheumatologists do recognize patients at risk for RA based on their clinical expertise and pattern recognition. So, they do recognize patients who have a combination of clinical characteristics that characterize the symptomatic prearthritis stage of RA. (This pattern is also called clinically suspect arthralgia,)” Dr. van der Helm–van Mil said in an interview.
However, the disadvantage of rheumatologists’ use of pattern recognition to identify patients at risk for RA is that it can be subjective, she said.
Several proof-of-concept trials are testing the hypothesis that the disease is more susceptible to disease-modifying treatment in the symptomatic prearthritis phase and that such early treatment might even prevent progression to chronic RA. But, selecting the “correct symptomatic patient” for early treatment with disease-modifying antirheumatic drugs is important, she said. Such a patient does not have clinical arthritis but is truly at risk for RA. Not all arthralgia patients are similar, and the type of arthralgia that is the hallmark for a heightened risk of progression to RA had not been defined formally prior to the EULAR definition.
A EULAR task force sought to provide some objective clarity by defining arthralgia at risk for RA (Ann Rheum Dis. 2017;76:491-6). The process relied on clinical expertise at all stages. However, until now, the definition had not been validated longitudinally. The current study used progression from arthralgia to clinical arthritis or RA as the outcome.
The definition of arthralgia at risk for RA hinges on seven parameters: symptom duration less than 1 year, symptoms in metacarpophalangeal joints, morning stiffness lasting an hour or more, symptoms that are worst in the morning, family history of RA, difficulty forming a fist, and positive squeeze test of metacarpophalangeal joints.
The researchers used those seven parameters to follow 241 Dutch patients considered likely to develop RA and 113 patients with recent-onset arthralgia in small joints who had not been evaluated by rheumatologists and who were referred to secondary care.
“The EULAR definition was developed for use in scientific studies and this definition is immediately applicable for this purpose,” Dr. van der Helm–van Mil said.
“With regards to application in daily practice, the clinical definition should be combined with results of additional investigations to accurately identify imminent RA in the phase of arthralgia. Which combination of markers yields the best accuracy is a subject for further studies,” Dr. van der Helm–van Mil said.
An important aspect of the task force’s definition is that rheumatologists should use it in patients in whom they consider imminent RA more likely than other diagnoses. The definition was not discriminative for RA when the investigators of the current study ignored this entry criterion, leading to a sensitivity of just 10% and positive predictive value of 3%.
“This suggests that the definition should be used in secondary care but may not be useful in primary care. However, more research is needed here,” Dr. van der Helm–van Mil said.
The authors reported no disclosures of interest.