DAS28(3)CRP is a reliable measure of disease activity in pregnant women with rheumatoid arthritis.

Abstract

The disease activity of rheumatoid arthritis (RA) in pregnancy is most commonly assessed with the modified Disease Activity Score (DAS)-28, the DAS28(3)CRP. However, the performance of the DAS28(3)CRP in pregnancy has not been compared to musculoskeletal ultrasound (MSK-US) as a gold standard. We performed a prospective pilot study to test the hypothesis that pregnancy-related factors limit the reliability of the DAS28(3)CRP. Pregnant women with RA were recruited from an Obstetric Rheumatology clinic and assessed during pregnancy (second (T2) and third (T3) trimesters) and postpartum with DAS28(3)CRP and MSK-US scores, with quantification of power Doppler (PD) signal in small joints (hands and feet). Age-matched non-pregnant women with RA underwent equivalent assessments. PD scores were calculated as mean scores of all joints scanned. We recruited 27 pregnant and 20 non-pregnant women with RA. DAS28(3)CRP was sensitive and specific for active RA in pregnancy and postpartum as defined by positive PD signal, but not in non-pregnancy. There were significant correlations between DAS28(3)CRP and PD scores throughout pregnancy (T2, r=0.82 (95% CI [0.42, 0.95], p<0.01); T3, r=0.68 (95% CI [0.38, 0.86], p<0.01)) and postpartum, r=0.84 (95% CI [0.60, 0.94], p<0.01), while this correlation in non-pregnancy was weaker (r=0.47 (95% CI [0, 0.77], p<0.05). This pilot study found that DAS28(3)CRP is a reliable measure of disease activity in pregnant women with RA. Based on these data, pregnancy does not appear to confound clinical evaluation of the tender and/or swollen joint counts.