AB0851 APPLICABILITY OF THE MASEI INDEX IN ENTHESIS AND ITS ASSOCIATION WITH OTHER INDICES / SEROLOGICAL MARKERS OF ACTIVITY IN PATIENTS WITH SPONDYLOARTHRITIS

Abstract

BackgroundSpondyloarthritis (SpA) are a group of chronic inflammatory diseases with affectation, mainly of the axial skeleton and, also, of peripheral joints. The enthesis is one of the target organs, since an inflammation of it, known as enthesitis, can be observed, which in many patients with spondyloarthritis could be unnoticed.ObjectivesFind the relation between the MASEI index (Madrid Sonographic Enthesitis Index) in entheses and other indices/serological activity markers (such as BASDAI, DAPSA or ASDAS and ESR, CRP) in spondyloarthritis patients.MethodsObservational, descriptive and cross-sectional study. Data were collected from patients with SpA who underwent musculoskeletal ultrasound using the Madrid Sonographic Enthesitis Index (MASEI) and who were treated in our clinics from May 2021 to September 2021 and under the approval of the CEICm of our center. The variables evaluated were described using measures of frequency and measures of central tendency/dispersion, as appropriate. First, we tested the normality of all the variables, using a Shapiro-Wilk test. We studied the correlation of parametric numerical variables (such as MASEI-Vitamin D, MASEI-ASDAS), using the Pearson coefficient. On the other hand, for non-parametric numerical variables (such as MASEI-BASDAI) we use Spearman’s coefficient. For parametric numeric and categorical variables (such as MASEI-VITAMINA D, ASDAS-VITAMINA D) we constrast the mean of differences using the T-Student test, while for non-parametric numerical and categorical variables, we contast the difference of means with the Mann-Whitney U test (MASEI-PCR, MASEI_VSG). Finally, to find out the correlation between categorical variables (such as VITAMIN D-PCR), we used a chi-square test. Finally, we have done a curve-fitting study with Matlab, obtaining the functions that better adjust the data avoiding overfitting. We have done this parametric optimization with the following pairings: MASEI-ASDAS, MASEI-BASDAI and MASEI DAPSA.ResultsWe analyze twenty four patients with SpA (with mean age 50.50 ± 10.63 years) 8 women and 16 men. They present: radiographic axial spondyloarthritis (5 patients), non-radiographic axial spondyloarthritis (4 patients), psoriatic arthritis (10 patients), spondyloarthritis associated with inflammatory bowel disease (2 patients), reactive arthritis (2 patients), and, finally, one patient has undifferentiated peripheral spondyloarthritis. The variables have the following average levels: ASDAS, 2.35 (±1.09); BASDAI (for those with axial involvement) 4.54 (±2.93); DAPSA (for psoriatic arthritis) 10.98 (± 6.85) and total MASEI 19.88 (± 14.77). We have found a correlation between the total MASEI and the following variables: ASDAS (Pearson coefficient=0.696), BASDAI (Spearman coefficient=0.823) and DAPSA (Pearson coefficient=0.823). The mean vitamin D levels were 25.98 (±12.05), and it has a negative correlation with the MASEI equal to -0.317. As far as curve fitting is concern, a couple of sinusoidal functions were obtained for the MASEI-ASDAS and MASEI DAPSA pairings (see Figure 1 and Figure 3) and a linear regression for MASEI-BASDAI (see Figure 2). These three curves have an R-squared fit of 0.77, 0.87 and 0.52, respectively.ConclusionPatients with spondyloarthritis who present greater activity of the disease measured by ASDAS, BASDAI/DAPSA and by the serological markers of inflammation CRP and ESR, present a higher total MASEI than patients who are controlled. In addition, it has been observed that patients with low levels of vitamin D have higher disease activity and a higher total MASEI.