Overdiagnosis and overtreatment in rheumatology: a little caution is in order

What is axial spondyloarthritis? A latent class and transition analysis in the SPACE and DESIR cohorts

OBJECTIVES

To gain expert-judgement-free insight into the Gestalt of axial spondyloarthritis (axSpA), by investigating its 'latent constructs' and to test how well these latent constructs fit the Assessment of SpondyloArthritis international Society (ASAS) classification criteria.

METHODS

Two independent cohorts of patients with early onset chronic back pain (SPondyloArthritis Caught Early (SPACE)) or inflammatory back pain (IBP) (DEvenir des Spondylarthopathies Indifférenciées Récentes (DESIR)) were analysed. Latent class analysis (LCA) was used to estimate the (unobserved) potential classes underlying axSpA. The best LCA model groups patients into clinically meaningful classes with best fit. Each class was labelled based on most prominent features. Percentage fulfilment of ASAS axSpA, peripheral SpA (pSpA) (ignoring IBP) or both classification criteria was calculated. Five-year data from DESIR were used to perform latent transition analysis (LTA) to examine if patients change classes over time.

RESULTS

SPACE (n=465) yielded four discernible classes: 'axial' with highest likelihood of abnormal imaging and HLA-B27 positivity; 'IBP+peripheral' with 100% IBP and dominant peripheral symptoms; 'at risk' with positive family history and HLA-B27 and 'no SpA' with low likelihood for each SpA feature. LCA in DESIR (n=576) yielded similar classes, except for the 'no-SpA'. The ASAS axSpA criteria captured almost all (SPACE: 98%; DESIR: 93%) 'axial' patients, but the 'IBP+peripheral' class was only captured well by combining the axSpA and pSpA criteria (SPACE: 78%; DESIR: 89%). Only 4% of 'no SpA' patients fulfilled the axSpA criteria in SPACE. LTA suggested that 5-year transitions across classes were unlikely (11%).

CONCLUSION

The Gestalt of axSpA comprises three discernible entities, only appropriately captured by combining the ASAS axSpA and pSpA classification criteria. It is questionable whether some patients with 'axSpA at risk' will ever develop axSpA.

Is the prevention of rheumatoid arthritis possible?

Preclinical phases of rheumatoid arthritis (RA) have been described, genetic and environmental risk factors for RA development have been identified, and several biomarkers of RA have been detected long before the clinical onset of the disease; all of which have opened the possibility for preventive interventions. Several studies are currently exploring pharmacological and non-pharmacological interventions to prevent the development of RA. We will review the evidence for prevention of RA and discuss key challenges for preventive interventions, including identification of the adequate target population, the risks of applying potentially harmful and expensive therapies to asymptomatic at-risk individuals, and the importance of taking into account the preferences of individuals at risk regarding preventive treatment options.

Measuring ACPA in the general population or primary care: is it useful?

Rheumatoid arthritis (RA) is associated with a significant disease burden and high costs for society. Because the disease has identifiable preclinical stages, screening and prevention have become a possibility in RA. Anticitrullinated peptide antibodies (ACPAs) are arguably the most likely candidate biomarker to screen for RA. This paper reviews the evidence for the use of ACPAs as a screening test in the broader general population, to identify individuals at high risk of subsequent onset of RA. We will review the diagnostic properties of the test and its positive and negative predictive value in different settings. We will discuss how ACPA testing could effectively be integrated in a broader screening strategy for RA.

Increased monohexosylceramide levels in the serum of established rheumatoid arthritis patients

Objectives

To identify serum sphingolipids that could act as candidate biomarkers in RA.

Methods

We performed lipidomic analyses in the serum of 82 participants: 19 established RA patients, 18 untreated early RA patients, 13 untreated early arthritis patients not fulfilling the classification criteria for RA, 12 established SpA patients and 20 controls. We compared the lipid levels from the different patient groups with the control group through multiple-regression analyses controlling for age at diagnosis, gender and medication (cDMARDs and corticoids).

Results

Established RA patients had significantly increased levels of sphingosine, monohexosylceramide and ceramide compared with controls, when controlling for age and gender. Monohexosylceramide levels remained significantly increased when additionally controlling for medication. On the contrary, SpA patients had significantly decreased levels of ceramide, in both analyses.

Conclusion

We observed a detectable increase in the levels of certain sphingolipids in the serum of established RA patients when compared with controls, in line with previous observations in the synovial fluid. Such findings provide further evidence that sphingolipids may play a key role in the pathophysiology of RA.

[Establishment of the current classification criteria for axial spondylarthritis, rheumatoid arthritis and SLE in routine practice of German rheumatologists]

BACKGROUND

In Germany, the numbers of patients with spondylarthritides (SpA) and rheumatoid arthritis (RA) have increased. This rise was possibly promoted by the introduction of new classification criteria (CC) that enable an earlier recognition and the inclusion of less severe cases. The study explores how the new CC for axial SpA (axSpA) are incorporated into the clinical practice, compared with the CC for RA and systemic lupus erythematosus (SLE). In addition, the study investigated whether the new entity of non-radiographic axSpA (nr-axSpA) is accepted and used in Germany.

MATERIAL AND METHODS

In 2016, an online survey was performed among all rheumatologists registered in the German Society of Rheumatology (DGRh). In addition, 150 rheumatologists were invited to the survey at the national meeting of the DGRh in 2016.

RESULTS

Among 119 participating rheumatologists, 99% were familiar with the new CC for SpA and 82% applied them in practice (RA 99% and 80%, SLE 50% and 56%). 78% differentiated between radiographic and nr-axSpA and 80% believed that a significant proportion of patients with nr-axSpA will never develop radiographic changes. 91% agreed that the new CC facilitated an earlier treatment start and 58% that the CC enabled more patients to receive biologicals. 50% shared the opinion that the criterion "chronic back pain" could lead to the classification of too many patients as having axSpA. It deemed possible to 65% that patients with nr-axSpA would be treated with biologicals in whom the diagnosis of axSpA could not be confirmed later on. 81% voted against the initiation of TNF inhibitors in nr-axSpA patients with normal CRP levels and normal MRI. 67% interpreted the MRI themselves and 30% stated that the MRI is evaluated according to validated standards by the radiologists. Among all axSpA criteria, HLA B27 and inflammatory back pain received the highest significance and the response to NSAID the lowest.

CONCLUSION

The new CC and the entity of nr-axSpA are accepted by German rheumatologists. A relevant proportion saw weaknesses of the new CC in the differentiation between nr-axSpA and non-specific chronic back pain. In practise, the interpretation of the CC with respect to the start of biologics is relatively strict, especially in cases with normal CRP and MRI. A ranking of axSpA criteria is commonly applied, although this was not initially intended in the CC.