Use of a screening questionnaire for systemic lupus erythematosus among pregnant women in a Mexican population

Abstract

Objective To conduct a diagnostic assessment of pregnant women using a screening questionnaire for SLE. Materials and methods This was an analytical cross-sectional study carried out at the National Institute of Perinatology between 1 November 2019 and 28 February 2020, using a screening questionnaire for SLE. Antinuclear antibody and anti-double stranded DNA antibody tests and a clinical assessment by a rheumatologist were conducted for participants who obtained ≥4 positive responses on the questionnaire. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the screening questionnaire for SLE were calculated. Results The questionnaire survey was conducted with 540 pregnant patients, 22 of whom (4.1%) had ≥4 positive responses. An antinuclear antibody test was conducted in all aforementioned 22 patients; 17 (77.3%) showed titres of ≥1:80. Of the 22 patients, 19 (86.4%) underwent clinical assessment by a rheumatologist. The patients were classified according to the SLE classification criteria: 7/19 (36.9%) met the revised 1997 American College Rheumatology (ACR) criteria, 8/19 (42.1%) met the Systemic Lupus International Collaborating Clinics criteria and 7/19 (36.9%) met the 2019 ACR/EULAR criteria (sensitivity=0.86, specificity=0.97, PPV=0.77 and NPV=1 for antinuclear antibody titre of ≥1:80; sensitivity=0.88, specificity=0.98, PPV=0.37 and NPV=1 for SLE according to the 2019 ACR/EULAR criteria). Conclusions The questionnaire showed high sensitivity and specificity in the diagnosis of SLE. Given its usability and cost:benefit ratio, this strategy should be used for all patients coming in for their first visit to determine who requires antinuclear antibody testing and who needs to be referred to a rheumatologist.