Alterations in erythrocyte deformability, aggregation, and blood viscosity in rheumatoid arthritis and systemic lupus erythematosus patients: A comparative haemorheological analysis.

ObjectivesThis study investigated haemorheological alterations in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE).MethodsA total of 136 individuals were enrolled, comprising 52 healthy controls, 51 RA patients, and 33 SLE patients. Blood samples were collected at the University of Health Sciences Sultan Abdulhamid Han Training and Research Hospital in Istanbul, Türkiye. Whole blood and plasma viscosity, along with red blood cell (RBC) deformability and aggregation, were analysed using a Brookfield viscometer and a laser-assisted optical rotational cell analyser (LORRCA).ResultsRBC deformability was reduced in both patient groups compared to controls (EImax: RA 0.645, SLE 0.642, control 0.648), while RBC aggregation was markedly increased (AI: RA 75.66, SLE 74.73, control 65.5) (p < 0.05). Plasma and whole blood viscosity were also elevated in RA and SLE groups, with the highest values observed in SLE patients (PV: RA 1.43, SLE 1.48, control 1.31).ConclusionsRA and SLE patients show notable impairments in haemorheological parameters. Evaluating RBC deformability, aggregation, and plasma viscosity may help clarify disease mechanisms and guide therapeutic strategies to mitigate vascular complications and tissue damage in autoimmune disorders.