The platelet indices in patients with rheumatoid arthritis: mean platelet volume reflects disease activity.

The present study was designed to investigate the interaction between platelet indices, inflammatory markers and disease activity in rheumatoid arthritis (RA) subjects. The effects of anti-TNF-alpha therapy and conventional treatment on platelet indices were also compared. We studied 97 patients with RA (19 men, 78 women: mean age 51 years) and 33 age and sex-matched healthy subjects as a control group. All RA patients were administered conventional therapy. After 3 months of therapy, 35 subjects who had high disease activity score (DAS28 > 5.1) were grouped as non-responders and were administered infliximab as a TNF-alpha blocker at the standard intravenous dose. Responders to the conventional therapy and non-responders were also compared. At baseline white blood cell (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), platelet count and mean platelet volume (MPV) were significantly higher in patients with RA. Mean platelet volume was positively correlated with DAS28 score (r = 0.27; p = 0.007). These markers of inflammation and platelet indices were substantially decreased after therapy. The reductions were similar in responders to conventional therapy and non-responders (TNF alpha group). In conclusion, we found that MPV was correlated with inflammatory markers and disease activity in patients with RA. Both anti-TNF-alpha and conventional therapy decreases markers of inflammation and platelet indices. MPV can reflect both disease activity and response to treatment.