Background Systemic Lupus Erythematosus (SLE) patients show higher Red blood cells Distribution Width (RDW) regardless of anaemia status1. RDW has been found to positively correlate with serum IgM, CRP, ESR, and SLE Disease Activity Index 2000 (SLEDAI-2K), and glucocorticoid treatment decreased both SLEDAI-2K and RDW2.
Objectives To determine whether RDW levels in SLE are associated with damage accrual.
Methods This cross-sectional study was conducted in 276 SLE patients, 257 females and 19 males. Evaluations included interview, medical records review, physical examination and laboratory tests. Disease activity was measured with the SLEDAI. Damage accrual was ascertained with the SLICC/ACR damage index (SDI). Univariable and multivariable Poisson regression models were performed to determine if RDW levels were associated with damage accrual. These models were stratified by tertiles of RDW. The multivariable model was adjusted for variables known to be associated with this outcome [age at diagnosis, gender, socioeconomic status, ethnicity, tobacco use, disease duration, SLEDAI, anemia, antimalarials and immunosuppressive drugs use, average daily dose and time of exposure to prednisone (PDN)].
Results The patients mean (SD) age at diagnosis was 34.38 (13.33) years; nearly all patients were mestizo. Disease duration was 7.04 (6.16) years. The SLEDAI was 5.24 (4.67) and the SDI 0.92 (1.28). The average daily dose of PDN was 6.90 (6.07) mg/d and the time of exposure to PDN was 6.58 (9.59) years. RDW levels were 14.57 (1.52)%. Hemoglobin levels were 12.4 (1.7) g/dl. We divided the RDW levels into tertiles with cut points in 13.8 and 14.0; the highest tertiles were associated with disease damage; with a Rate Ratio (RR) 1.57 (1.07–2.28; p: 0.020 for the highest tertile, and 1.67 (1.15–2.42; p: 0.007) for the medium tertile.
Conclusions Higher RDW levels are associated with damage accrual in SLE patients independent of other well-known risk factors for such occurrence.
Vayá A, Alis R, Hernández J-L, et al. RDW in patients with systemic lupus erythematosus. Influence of anaemia and inflammatory markers. Clin Hemorheol Microcirc 2013; 54: 333–9.
Hu Z-D, Chen Y, Zhang L, et al. Red blood cell distribution width is a potential index to assess the disease activity of systemic lupus erythematosus. Clin Chim Acta 2013; 425: 202–205.
Disclosure of Interest None declared