Serum RDW and MPV in Ankylosing Spondylitis: Can they show the disease activity?

To determine RDW and MPV levels in Ankylosing Spondylitis (AS) and to investigate their relations with disease activity.

133 patients with AS (male: 80, female: 53) and age-sex matched 133 controls (male: 79, female: 54) were enrolled. Demographic data, disease activity scores, Complete Blood Count (CBC), Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) levels were recorded.

The mean ages of patients and controls were 41.9±11.2 and 39.7±14.2 years respectively (p = 0.16). RDW (14.5±1.6% and 13.2±0.8%, p < 0.0001 respectively) and MPV (10.1±0.8fl and 9.9±0.7fl, p = 0.03, respectively) were significantly higher in patients with AS than in controls. There was a significant difference in RDW between patients with active AS (Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) >4) and those with inactive AS (BASDI <4) patients (14.84±1.79fl, 14.24±1.37fl, p = 0.035 respectively). RDW was positively correlated with BASDAI (r = 0.33, P < 0.0001), ESR (r = 0.45, P < 0.0001) and CRP (r = 0.42, P < 0.0001) and PLT levels (r = 0.24, P = 0.004). While MPV was not correlated with BASDAI, it was negatively correlated with ESR (r = -0.19, P = 0.03), CPR (r = -0.26, P = 0.004) and PLT levels (r = -0.39, P = <0.0001).

RDW and MPV were significantly higher in the patients with AS than in the controls. While RDW was correlated with BASDAI and APRs, MPV was only correlated with APRs.