Association between mean platelet volume and severity of rheumatoid arthritis

INTRODUCTION: In recent years, it is suggested that platelet histogram indices, such as mean platelet volume (MPV) may be related to the activity of rheumatoid arthritis (RA). The aim of this study was to assess relationship between MPV and activity of rheumatoid arthritis. METHODS: Sixty consecutive patients fulfilling the American College of Rheumatology (ACR) criteria for RA were recruited from the rheumatology outpatient clinics in Semnan, Iran. Current disease activity score (DAS-28 score) was assessed at baseline, 2 months and 4 months after the admission time and beginning of the treatment schedule. Complete blood count (including MPV), C-reactive protein (CRP) and ESR were measured in each visit. MPV was analyzed by the Cell Dyne 3500 automated blood cell counter. RESULTS: There was a significant reduction in DAS-28 score within 4 months of total assessment (from 4.47 ± 2.24 versus 3.18 ± 1.55) (p < 0.001). There was no significant difference in MPV levels at the three study time points. No significant correlations were observed between the DAS-28 score and mean MPV levels at the same time points. The rate of positive CRP was decreased within the same period (p = 0.002); however, the trend of the changes in other laboratory parameters including MPV, platelet count and ESR values was not significant. The measurement of MPV value did not correlate with disease activity in RA patients within 4 months of treatment scheduling. CONCLUSION: Although therapeutic regimens, which improve RA manifestations, can reduce RA activity, they had no effect on MPV during this time period. It seems MPV may not be able to predict disease activity in RA patients.