First Diagnosis of Systemic Lupus Erythematosus in Hospitalized Patients: Clinical Phenotypes and Pitfalls for the Non-Specialist

Prompt recognition of systemic lupus erythematosus (SLE) in hospitalized patients presenting with severe disease is essential to initiate treatment. We sought to characterize the phenotype of hospitalized patients with new-onset SLE and estimate potential diagnostic delays. An observational study of 855 patients (“Attikon” SLE cohort). Clinical phenotype was categorized according to the leading manifestation that led to hospitalization. Disease features, time to diagnosis, classification criteria, and the SLE Risk Probability Index (SLERPI) were recorded for each patient. There were 191 patients (22.3% of the total cohort) hospitalized due to manifestations eventually attributed to SLE. Main causes of admission were neuropsychiatric syndromes (21.4%), cytopenias (17.8%), nephritis (17.2%), and thrombotic events (16.2%). Although 79.5% of patients were diagnosed within 3 months from hospitalization, in 39 patients diagnosis was delayed, particularly in those with hematological manifestations. At hospitalization, a SLERPI >7 (indicating high probability for SLE) was found in 87.4% of patients. Patients missed by the SLERPI had fever, thrombotic or neuropsychiatric manifestations not included in the algorithm. Lowering the SLERPI threshold to 5 in patients with fever or thrombotic events increased the diagnostic rate from 88.8% to 97.9% in this subgroup, while inclusion of all neuropsychiatric events yielded no additional diagnostic value. One in five patients with new-onset SLE manifest disease presentations required hospitalization. Although early diagnosis was achieved in the majority of cases, in approximately 20%, diagnosis was delayed. A lower SLERPI cut-off (≥5) in patients with fever or thrombosis could enhance early diagnosis.