Background:Disease activity in patients with axial spondyloarthritis (axSpA) can be measured by BASDAI and ASDAS. Both instruments were validated in non-pregnant patients with cutoff values for active diseases. In pregnant women with axSpA, however, BASDAI and ASDAS scores might be biased by signs and symptoms of pregnancy itself.Objectives:To compare the performance of ASDAS and BASDAI during pregnancyMethods:Patients with axSpA were prospectively followed before pregnancy, at each trimester and 6 to 12 weeks postpartum. Disease activity was assessed by BASDAI, ASDAS, patient global assessment (PGA) and physician global assessment (PhGA). We analysed the disease course throughout pregnancy and postpartum, the correlation between BASDAI and ASDAS and the agreement in the classification of active disease. We applied receiver operating curves (ROC) to evaluate the cut-off points in pregnant patients.Results:The study involved 40 women with axSpA. Disease activity scores were higher during pregnancy (median ASDAS score: 2.5, median BASDAI score 3.1) than during a non-pregnant state (median ASDAS score 2.3, median BASDAI score 2.1). Median BASDAI scores were highest at the first trimester, median ASDAS scores were highest at the second trimester. ASDAS strongly correlated with BASDAI, both in the pregnant and in the non-pregnant state (r=0.796, r=0.727). However, there was a discordance when analysing the proportion of patients with high disease activity using the common cut-off values (ASDAS >2.1, BASDAS >4). More patients had high disease activity when measured by ASDAS (1st trimester (T): 63%, 2nd T: 76%, 3rd T: 61%) compared to those measured by BASDAI (1st T 43%, 2nd T: 39%, 3rd T: 34%). The κ coefficient showed only fair agreement (κ=0.39). ROC analysis among pregnant patients showed that the cut-off point estimation for high disease activity using ASDAS >2.75 corresponded to a BASDAI >4. The ASDAS >2.75 cut-off for high disease activity had a good agreement with BASDAI >4 (κ=0.657). When ASDAS >2.75 was applied in pregnant women with axSpA, about 40% experienced high disease activity.Conclusion:During pregnancy, the majority of women with axSpA experience ongoing disease activity. However, the cut-off values defining low and high disease activity might differ between pregnant and non-pregnant individuals since BASDAI and ASDAS are biased by pregnancy related symptoms like fatigue and mechanical back pain.Disclosure of Interests:None declared.
Inference for the Exponential Distribution under Generalized Progressively Hybrid Censored Data from Partially Accelerated Life Tests with a Time Transformation Function
