medwireNews: Elevated levels of fecal calprotectin (F-calprotectin), an indicator of gut inflammation, are associated with increased disease activity and reduced physical function in patients with axial spondyloarthritis (axSpA), research shows.
The interim analysis of the SPARTAKUS study, conducted by Johan Wallman (Skåne University Hospital, Lund, Sweden) and colleagues, found that 27% of 40 patients with nonradiographic (nr)-axSpA had elevated F-calprotectin (≥50 mg/kg).
This proportion was significantly lower than the 38% of 90 patients with ankylosing spondylitis (AS) who had elevated F-calprotectin, but significantly higher than the rate of 6% observed among 35 healthy controls, the researchers report in Rheumatology.
After adjustment for age, sex, and Assessment of SpondyloArthritis International Society nonsteroidal anti-inflammatory drug (NSAID) score, mean F-calprotectin levels were significantly higher among the patients with AS and nr-axSpA than among the controls, at 41 and 24 versus 12 mg/kg, respectively, but there was no significant difference between the two axSpA groups.
When the two groups were combined, Wallman and team found that, after adjustment for age, sex, NSAID use, antirheumatic treatments, and C-reactive protein (CRP), axSpA patients with elevated versus normal F-calprotectin levels had significantly higher scores on a visual analog scale for global health (43 vs 31 mm), with higher scores indicating worse global health.
They also report worse outcomes on the ASDAS-CRP (2.3 vs 1.8) and on the BASFI (3.3 vs 2.2) for patients with elevated compared with normal F-calprotectin.
When the team looked at anti-Saccharomyces cerevisiae antibody (ASCA) titers they found that seropositivity rates for IgA and IgG were similar between patients with nr-axSpA (IgA/IgG-seropositivity: 8%/26%) and those with AS (7%/28%).
The rates were significantly higher than those observed in the control group for IgA, where none of the patients were seropositive, and also higher for IgG in the AS group, but not the nr-axSpA group, than in the control group (17%).
However, ASCA levels were not associated with axSpA outcomes for any of the measures studied and there was also no association between gastrointestinal symptoms and elevated levels of ASCA or F-calprotectin.
Wallman et al conclude that their findings “are well in line with previous observations, showing more pronounced sacroiliitis in patients with microscopic gut inflammation, thus providing further evidence for an important interplay between gastrointestinal and musculoskeletal manifestations of axSpA.”
By Laura Cowen
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