Assessment of Ankylosing Spondylitis Activity During Pregnancy Using Different Disease Activity Indices

Objective: Assessment of ankylosing spondylitis activity patterns during pregnancy using BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) and ASDAS-CRP (Ankylosing Spondylitis Disease Activity Score — C-Reactive Protein) disease activity indices.Materials and methods. The prospective study included 36 pregnant women with AS (modified New York AS criteria, 1984). Patients’ mean age was 31.6±4.8 years, mean age at AS onset was 21.8±10.9, and disease duration 134.9±89.3 months. The control group included 30 healthy pregnant women with no history of back pain and arthritis, their mean age was 28.2±4.5 years. In the I trimester of pregnancy 10 (33.3%) As patients experienced back pain, while in the III trimester already 15 (50%) had back pain. Throughout pregnancy, the intensity of back pain in the I, II и III trimesters based on numeric scale was on average 1.9±0.9; 2.1±1.1 and 2.1±0.8. BASDAI and ASDAS-CRP were used to measure disease activity on gestational Weeks 10–11, 20–21 and 31–32. The time of conception BASDAI score was assessed retrospectively at the 1st visit.Results and discussion. BASDAI mean values at the time of conception and I, II и III trimesters of pregnancy were: 2.3±1.9; 2.8±1.72 (p0.7) of fatigue severity with the BASDAI index in the I and II trimesters of pregnancy and moderate correlation (rs >0.53) in the III trimester; as wells as moderate (rs >0.5-0.69) correlation between back pain and BASDAIConclusion. A trend towards increasing AS activity based on BASDAI and ASDAS-CRP scores and CRP levels was established for the first half of pregnancy. Later in pregnancy these increased values failed to return to normal until the end of gestation. The percentage of AS patients with highto-moderate disease activity throughout pregnancy was lower based on BASDAI score vs based on ASDAS-CRP. Some BASDAI components (fatigue and back pain) reflect not only the activity of AS, but also changes associated with physiological pregnancy. The BASDAI index requires adaptation for use in pregnancy