Comparison of the SLE Risk Probability Index (SLERPI) scale against the European League Against Rheumatism/American College of Rheumatology (ACR/EULAR) and Systemic Lupus International Collaborating Clinics (SLICC) criteria

Abstract

Introduction: Timely diagnosis and proper recognition of Systemic Lupus Erythematosus (SLE) is essential to establish early management in inpatients and outpatients. There are different classification scales to identify SLE, which include various clinical and serological aspects. In 2021, the SLE Risk Probability Index (SLERPI) was published, which focuses predominantly on the clinical characteristics of patients with suspected SLE and uses a simple algorithm for early recognition of the disease. The aim of this study is to compare the European League Against Rheumatism/American College of Rheumatology (ACR/EULAR) classification criteria, the Systemic Lupus International Collaborating Clinics (SLICC) criteria, and the SLERPI criteria in a cohort of Colombian patients with SLE and to analyze the correlations observed between their absolute scores.

Methods: A registry of SLE patients from two referral hospitals in Bogotá, Colombia, was used. 2021 SLERPI, 2019 ACR/EULAR, and 2012 SLICC scores were calculated for each patient and the correlations found between the scales were analyzed. The sensitivities of each were compared, and frequency analyses were conducted among different clinical and laboratory variables.

Results: Between 2016 and 2019, 146 patients diagnosed with SLE were registered, including inpatients and outpatients. The median age was 36 years (interquartile range 26-51), and 82.2% were women. According to the SLERPI criteria, a high prevalence of antinuclear antibodies (92%), immunological disorders (71%), and arthritis (64%) were observed. The most used treatments were corticosteroids (87.6%) and chloroquine (67.8%). A Spearman evaluation analysis was performed, with a moderately strong correlation of 0.76 (p = .000) between the SLERPI and ACR/EULAR scales and very strong correlation of 0.80 (p = .000) between the SLERPI and SLICC. Patients classified with SLE according to the SLERPI scale exhibited a higher incidence of hematological compromise, along with elevated levels of serological markers such as anti-DNA antibodies. Additionally, this group more commonly received treatments involving corticosteroids and azathioprine, and displayed a higher prevalence of hypertension.

Conclusion: The SLERPI scale could be useful in the diagnosis of SLE, especially in early stages, given its good correlation with other classification scales and its good sensitivity.

Keywords: Lupus erythematosus; SLE Risk Probability Index; diagnosis; systemic.