Randomised prospective trial to assess the clinical utility of multianalyte assay panel with complement activation products for the diagnosis of SLE

• Type of Material: Article
• Authors: Daniel J. Wallace, Cedars Sinai Medical Center; Roberta Vezza Alexander, Exagen; Tyler O'Malley, Exagen; Arezou Khosroshahi, Emory University; Mehrnaz Hojjati, Loma Linda University; Konstantinos Loupasakis, MedStar Washington Hospital Center; Jeffrey Alper, Bendcare; Yvonne Sherrer, Bendcare; Maria Fondal, Bendcare; Rajesh Kataria, Southern Ohio Rheumatol; Tami Powell, Exagen; Claudia Ibarra, Exagen; Sonali Narain, Northwell Health; Elena Massarotti, Brigham & Womens Hospital; Arthur Weinstein, Exagen; Thierry Dervieux, Exagen
• Language: English
• Date: 2019-01-01
• Publisher: BMJ PUBLISHING GROUP
• Publication Version: Final Published Version
• Copyright Statement: © Author(s) (or their employer(s)) 2019.
• License: Creative Commons Attribution-NonCommercial 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1136/lupus-2019-000349
• Title of Journal or Parent Work: LUPUS SCIENCE & MEDICINE
• Volume: 6
• Issue: 1
• Start Page: e000349
• End Page: e000349
• Grant/Funding Information: This study was funded by Exagen.
• Keywords: LUPUS; Science & Technology; ACCURACY; Rheumatology; VALIDATION; Life Sciences & Biomedicine
• Research Categories: Biology, Cell; Health Sciences, Pharmacology; Health Sciences, Health Care Management

Abstract

Objective We compared the physician-assessed diagnostic likelihood of SLE resulting from standard diagnosis laboratory testing (SDLT) to that resulting from multianalyte assay panel (MAP) with cell-bound complement activation products (MAP/CB-CAPs), which reports a two-tiered index test result having 80% sensitivity and 86% specificity for SLE. Methods Patients (n=145) with a history of positive antinuclear antibody status were evaluated clinically by rheumatologists and randomised to SDLT arm (tests ordered at the discretion of the rheumatologists) or to MAP/CB-CAPs testing arm. The primary endpoint was based on the change in the physician likelihood of SLE on a five-point Likert scale collected before and after testing. Changes in pharmacological treatment based on laboratory results were assessed in both arms. Statistical analysis consisted of Wilcoxon and Fisher's exact tests. Results At enrolment, patients randomised to SDLT (n=73, age=48±2 years, 94% females) and MAP/CB-CAPs testing arms (n=72, 50±2 years, 93% females) presented with similar pretest likelihood of SLE (1.42±0.06 vs 1.46±0.06 points, respectively; p=0.68). Post-test likelihood of SLE resulting from randomisation in the MAP/CB-CAPs testing arm was significantly lower than that resulting from randomisation to SDLT arm on review of test results (-0.44±0.10 points vs -0.19±0.07 points) and at the 12-week follow-up visit (-0.61±0.10 points vs -0.31±0.10 points) (p<0.05). Among patients randomised to the MAP/CB-CAPs testing arm, two-tiered positive test results associated significantly with initiation of prednisone (p=0.034). Conclusion Our data suggest that MAP/CB-CAPs testing has clinical utility in facilitating SLE diagnosis and treatment decisions.