The term ‘non-radiographic axial spondyloarthritis’ (nr-AxSpA) is much more important to classify than to diagnose patients with axial spondyloarthritis.
So, is nr-AxSpA the same animal as AS, but its "younger self"? Do all nr-AxSpA progress eventually to AS? Are treatments that work for AS and are approved for AS recommended for nr-AxSpA, or would these expensive biologics be an overkill if most nr-AxSpA do not progress to AS?
We need answers.
Depending on the duration of the study you are looking at, the percentage of nr-AxSpA progressing to AS varies, with longer studies generally yielding higher proportions.
While the previous study yielded 26% of nr-AxSpA progressing to AS over 10 years, the figure understandably came in at <5% in this study of a mere 2-years' duration.
It would be logical to say that some (not all, or even a majority) nr-AxSpA patients progress, and at different rates.
The next step is to determine what are the predictive factors for rapid structural progression, so as to treat these patients earlier and more aggressively (with biologics, perhaps) to forestall damage and disability.
It appears that nr-AxSpA has a female preponderance, and a consistently lower CRP (reflecting inflammatory burden) throughout the disease course. Response to treatment with anti-TNFs and compliance with therapy did not differ between the groups, with those with higher CRP (possibly more symptomatic and debilitating disease) responding better to and complying better with treatment.
So, it appears that nr-AxSpA represents a milder and earlier form of AS, and warrants treatment like AS, to be titrated according to the inflammatory burden (symptoms, CRP, MRI).
It seems that progression on the nr-AxSpA to AS spectrum is not inexorably one-way: some "damage" visualised on XRays may potentially repair/improve😊 The authors urged caution as the small XRay changes either way may have been misread😔