Extremely high erythrocyte sedimentation rate revisited in rheumatic diseases: a singlecenter experience.

Background: The objectives were to define the distribution of rheumatic diseases in patients with erythrocyte sedimentation rate (ESR) ≥ 100 mm/h and to find variables that can differentiate main study groups from others.

Methods: Charts of patients admitted with ESR ≥ 100 mm/h between 2015 and 2020 were reviewed. Patients were divided into four diagnostic groups based on etiology: infection (without a rheumatic diagnosis), oncologic (without a rheumatic diagnosis), rheumatic, and no definitive diagnosis. Patients with the rheumatic diagnosis were divided into three main study groups: those who had been recently diagnosed with a rheumatic disease, those who had a flare-up of the rheumatic disease, and those who had an infection in the course of the rheumatic disease. Appropriate statistical tests and decision-tree analysis by R and ROC curve were applied. p < 0.05 was considered statistically significant.

Results: A total of 2442 patients (311 (12.7%) with rheumatic disorders) were identified. Eightysix (27.7%) patients had newly diagnosed rheumatic disease (41; 47.7% with vasculitis); 111 (35.7%) had rheumatic disease flare-up (92; 82.9% with inflammatory arthritis); and 114 (36.6%) had coexisting infection (61; 53.5% inflammatory arthritis). Irrespective of the study group, the most commonly encountered diseases were rheumatoid arthritis and spondyloarthritis. Serum albumin levels (2.78 mg/dL) and platelet count (290/mm6 ) were valuable to discriminate disease flare-up and coexisting infection; moreover, high ferritin levels were accounted for adult-onset Still disease among patients with newly diagnosed rheumatic diseases.

Discussion: Extremely high ESR is still a valuable clinical parameter, and rheumatic causes are significant besides malignancy and infections. Albumin, thrombocyte count, and ferritin are other tests that clinicians should consider when caring for a patient with ESR ≥ 100 mm/h who has rheumatic disease.