The Clinical Significance Of Mean Platelet Volume For Assessment Of Disease Activity And Severity In Systemic Lupus Erythematosus

Objective: Mean platelet volume(MPV),an indicator of platelet size,is thought to correlate with platelet activity.As a common and convenient indicator of inflammation,it has drawn more and more attention in the scopes of acute coronary syndrome,atherosclerosis,cardiovascular and cerebrovascular complications of chronic kidney disease(CKD)and rheumatoid arthritis(RA)in recent years.Systemic lupus erythematosus(SLE)is accompanied with significant platelet activation.Several literature reported that MPV could be a predictive biomarker for SLE and this parameter would be changed in paralled with the activity indexes.However,the conclusions are inconsistent.Then,this study was to explore the association between MPV and the disease activity in adult patients with SLE,and to provide a new simple and convenient index for the activity evaluation of SLE.Methods:In this retrospective study,699 cases who diagnosed as SLE in the First Affiliated Hospital of Suzhou University were included,and divided into four groups according to the SLEDAI-2000 as following,0-4 scores as the no active group(G1),5-9 scores as the mild active group(G2),10-14 scores as the moderate active group(G3),?15 scores as the severe active group(G4).According to kidney involvement or not,these cases were divided into lupus nephritis group and non-nephritis group.The laboratory parameters of each patient were recorded,including body mass index(BMI),platelet count(PLT),mean platelet volume(MPV),platelet distribution width(PDW),red blood cell count(RBC),hemoglobin(HB),white blood cell count(WBC),erythrocyte sedimentation rate(ESR),complement C3(C3),complement C4(C4),C-reactive protein(CRP),serum albumin(ALB),prealbumin(PA),24-hour urine protein(UTP)and estimated glomerular filtration rate(e GFR).SPSS22.0 was used to compare the differences of MPV among the four groups of SLE patients with different degrees of activity,as well as between lupus nephritis and non-lupus nephritis,and to evaluate the correlation between MPV and SLEDAI score.Results: Among 699 cases with SLE,103(14.7%),179(25.6%),274(39.2%)and 143(20.5%)patients were classified as G1 to G4,respectively.One-Way ANOVA analysis showed that MPV had no significant difference among groups(P=0.241).It showed statistically significant of PLT,RBC,HB,ESR,C3,C4,CRP,PA,ALB,UTP and e GFR with SLEDAI score in each group(P <0.05).Spearman correlation analysis showed that there was no significant correlation between MPV,PDW and SLEDAI score.There was a negative correlation between PLT,RBC,HB,C3,C4,ALB,PA and SLEDAI score.ESR,CRP,UTP were positively correlated with SLEDAI score.MPV is negatively correlated with PLT.Multivariate linear regression analysis suggested that SLEDAI score was independently associated with C3 and ALB.There were 346 cases(49.5%)in lupus nephritis group and 353 cases(50.5%)in non-nephritis group.There was no significant difference between the two groups in MPV(P = 0.322),while a significant one in PLT(P=0.017).Conclusions: This study showed,for the first time,that MPV has no association with the activity of SLE and lupus nephritis.It seemed that MPV has no advantage in assessing the severity of SLE,which is different from other people's previous researches.The traditional indexes,such as PLT,C3,C4,ALB,ESR,CRP,may reflect platelet activity,C3 and ALB are still independent biomarkers for SLE activity.