Study On The Association Between Mean Platelet Volume/Platelet Count Ratio And The Short-term Outcome Of Acute Ischemic Stroke

BackgroundStroke has become the first cause of death and disability in adults in China,of which ischemic stroke is the most common type,accounting for about 87%of all strokes.With the development of the aging population,the incidence of ischemic stroke increases year by year,and the recurrence rate,disability rate and mortality rate remain high,causing a serious economic burden.Therefore,it is of great clinical value to find predictive indexes that may be related to the prognosis and outcome of ischemic stroke.Activated platelets play an important role in the progression of ischemic stroke by causing thrombosis and vascular occlusion.Mean platelet volume(MPV)is a sign of platelet activation and has a negative correlation with platelet count(PC).At present,the importance of MPV/PC ratio as a composite indicator in diseases of different systems has been widely concerned.Numerous studies have proved that the MPV/PC ratio is a powerful predictor of survival risk for cancer patients and is associated with mortality from ischemic cardiovascular diseases such as acute myocardial infarction.In terms of cerebrovascular disease,the MPV/PC ratio has been shown to be related to the risk of death in patients with ischemic stroke and pneumonia.However,there is no relevant research confirming whether the MPV/PC ratio can predict the functional prognosis of patients with acute ischemic stroke.ObjectiveThe purpose of this study was to investigate the correlation between the MPV/PC ratio and the short-term functional prognosis of acute ischemic stroke.MethodsThis study was a prospective observational cohort study.The data were from the ischemic stroke database of the First Affiliated Hospital of Zhengzhou University.Patients diagnosed with acute ischemic stroke in the department of neurology,department of neurological intervention and emergency department of the First Affiliated Hospital of Zhengzhou University from January 2015 to December 2017 were continuously included,and the first venous blood sample collection was completed within 24 hours after admission.All patients completed baseline data collection,neurological function assessment,venous blood sample collection,and MPV and PC level testing.Neurological function was assessed by the National Institute of Health stroke scale(NIHSS),and admission NIHSS?4 points was defined as mild acute ischemic stroke.The included patients with acute ischemic stroke were followed up by telephone or face to face 3 months after onset.Functional prognosis was assessed using the modified Rankin scale(mRS),and adverse functional prognosis(mRS score>2)was the endpoint event for a prospective observational cohort study.Statistical analysis was performed using SPSS 19.0(Statistical Product and Service Solutions version 19.0)and MedCalc 19.2.0 and R 3.6.3 software.The Kolmogorov-Smirnov test was used to assess the distribution of continuous variables.The continuous variables of normal distribution were expressed as mean ±standarddeviation.The continuous variable of non-normal distribution is represented by median(quartile spacing),and the Mann-Whitney U test is used for the difference analysis.Classification variables are expressed as numbers(percentages)and analyzed by chi-square test.Logistic regression analysis was used to evaluate the effect of MPV/PC ratio on functional prognosis of patients with acute ischemic stroke at 3 months after onset,and the odds ratio(OR)and 95%confidence interval(CI)were calculated.Gender,age,common risk factors for stroke(smoking within half a year,hypertension,previous stroke,coronary heart disease,atrial fibrillation,diabetes mellitus,hyperlipidemia)and admission NIHSS score were adjusted for in the multivariate analysis.Logistic regression analysis and Bootstrap method were used to test the interaction of multiplication and addition between MPV/PC ratio and other factors.Among them,the estimation of Bootstrap resampling and confidence interval can be realized by loading Boot software package in R language,and three important indicators of the interaction intensity of the additive model can be calculated:Relative excess risk due to interaction(RERI),attributable proportion due to interaction(AP)and synergy index(S)and the confidence interval of the three.When the confidence interval of RERI and AP contains 0 and the confidence interval of S contains 1,it is considered that the additive model interaction does not exist.The receiver operating characteristic(ROC)curve was plotted to obtain a cutoff value at the level of the MPV/PC ratio with the best accuracy(sensitivity and specificity)in identifying functional outcomes of acute ischemic stroke.The patients were divided into two groups according to the optimal truncation value,and the superimposed bar chart of the percentage of functional outcomes of patients with acute ischemic stroke 3 months after the onset was plotted.In addition,C statistics,integrated discrimination improvement(IDI)and net reclassification index(NRI)were used to evaluate the incremental predictive power of MPV/PC ratio over admission NIHSS score in functional prognosis of patients with acute ischemic stroke.All statistical analyses were performed by bilateral test at the level of bilateral=0.05.Results1.A total of 1158 patients with acute ischemic stroke were included.In the follow-up 3 months after the onset,56 patients(4.8%)were lost to follow-up,and 1102 patients finally entered the prognosis analysis.Within 24 hours,the MPV/PC ratio of patients with poor functional prognosis 3 months after the onset of acute ischemic stroke was significantly higher than that of the patients with good prognosis[39.45(32.02-53.85)vs.38.76(30.20-49.46)fL/1012/L;P=0.042],while there was no statistically significant difference between MPV and PC(P>0.05).2.Univariate logistic regression analysis showed that MPV(OR:1.163,95%CI:1.017-1.329,P=0.027),PC(OR:0.977,95%CI:0.994-1.000,P=0.036)and MPV/PC ratio(OR:1.011,95%CI:1.004-1.019,P=0.004)in patients with acute ischemic stroke were all associated with poor functional prognosis 3 months after onset.After multivariate logistic regression analysis was used to adjust for gender,age,smoking history within half a year,hypertension,previous stroke,coronary heart disease,atrial fibrillation,diabetes mellitus,hyperlipidemia and admission NIHSS scores,MPV(P=0.192)and PC(P=0.069)had no significant correlation with functional prognosis 3 months after the onset of acute ischemic stroke.The MPV/PC ratio was still a predictor of poor functional prognosis 3 months after the onset of acute ischemic stroke(OR:1.011;95%CI:1.002 1.020;P=0.021).The results of interaction test showed that there was no significant multiplicative and additive interaction between MPV/PC ratio and gender,smoking,hypertension,previous stroke,coronary heart disease,atrial fibrillation,diabetes,and hyperlipidemia,and there was an additive interaction between MPV/PC ratio and the severity of acute ischemic stroke.The results of subgroup analysis by multivariate logistic regression showed that in patients with mild acute ischemic stroke(admission NIHSS?4),the MPV/PC ratio was associated with the prognosis of adverse functions 3 months after the onset(OR:1.014;95%CI:1.0021.026;P=0.026),but not in patients with mild acute ischemic stroke(OR:1.008;95%CI:0.994 1.021;P=0.266).3.According to ROC curve analysis of functional prognosis 3 months after the onset of acute ischemic stroke,the optimal cut-off value of MPV/PC ratio was 29.57 fL/1012/L,with sensitivity of 88.46%and specificity of 23.37%.According to the optimal truncation value of MPV/PC ratio,1102 patients were divided into two groups:?29.57 and>29.57 fL/1012/L.The MPV/PC ratio of>29.57 fL/1012/L group had a significantly higher proportion of patients with poor functional prognosis(P<0.001).Compared with the admission NIHSS score alone,the comprehensive MPV/PC ratio and admission NIHSS score were 0.68%(P=0.037)for NRI and 4.17%(P=0.024)for IDI in patients with acute ischemic stroke.Conclusions1.The higher the MPV/PC ratio,the higher the risk of poor functional outcome 3 months after the onset of acute ischemic stroke.MPV/PC ratio can be used as a predictor of poor short-term functional prognosis in patients with acute ischemic stroke.2.Compared with patients with non-mild acute ischemic stroke,MPV/PC ratio has a stronger ability to predict short-term functional prognosis of patients with mild acute ischemic stroke.3.MPV/PC ratio can enhance the ability of admission NIHSS score to predict short-term functional prognosis of patients with acute ischemic stroke.