Objective To explore the correlation between platelet to lymphocyte ratio(PLR),neutrophil to lymphocyte ratio(NLR)and carotid atherosclerotic(CAS)plaque in patients with type 2 diabetes(T2DM),and the predictive value of PLR and NLR for T2DM complicated with CAS plaque.Methods A total of 369 T2DM patients admitted to the Department of Endocrinology,the Third Affiliated Hospital of Xinxiang Medical University from September 2019 to November 2021 were se-lected as research subjects.The clinical data such as gender,age,course of disease,body mass index(BMI),systolic blood pressure(SBP),diastolic blood pressure(DBP),personal history,and history of past illness of patients were collected by searching the electronic medical record system.Neutrophil(NC)count,lymphocyte count(LC)and platelet(PLT)count were detected by fully automated blood routine analyzer,and PLR,NLR were calculated;the levels of fasting blood glucose(FBG),total cholesterol(TC),triglycerides(TG),high-density lipoprotein-cholesterol(HDL-C)and low-density lipoprotein-cholesterol(LDL-C)were detected by biochemical analyzer;the level of glycosylated hemoglobin(HbA1c)were detected by high-performance liquid chromatography.The T2DM patients were divided into T2DM uncomplicated with CAS plaque group(n=94)and T2DM complicated with GAS plaque group(n=275)based on whether they complicated with CAS plaque or not;the general clinical data,blood indicators,and PLR,NLR of patients were compared between the two groups.The T2DM patients were divided into non plaque group(group A,n=94),1 plaque group(group B,n=79),2 plaque group(group C,n=89),and 3 or more plaques group(group D,n=107)based on the number of CAS plaques;the indicators with statistical differences between T2DM uncomplicated with CAS plaque group and T2DM complicated with CAS plaque group of patients were compared among the four groups.According to the PLR quartile,the patients were divided into P1 group(PLR≤94.87,n=93),P2 group(94.87＜PLR≤117.30,n=91),P3 group(117.30＜PLR ≤ 148.53,n=93),and P4 group(PLR＞148.53,n=92),and the detection rate of CAS plaques of patients was compared among the four groups;according to the NLR quartile,the patients were divided into N1 group(NLR≤1.59,n=92),N2 group(1.59＜NLR≤1.93,n=92),N3 group(1.93＜NLR≤2.50,n=93),and N4 group(NLR＞2.50,n=92),and the detection rate of CAS plaque of patients was compared among the four groups.The risk factors of T2DM complicated with CAS plaque was analysed by multivariate logistic regression analysis,and the predictive efficacy of PLR and NLR for T2DM complicated with CAS plaque were evaluated by receiver operating characteristic(ROC)curve.Results The age,course of T2DM,proportion of patients combined with hyper-tension,SBP,PLR,and NLR of patients in the T2DM complicated with CAS plaque group were significantly higher than those in the T2DM uncomplicated with CAS plaque group,while LC and TG levels were significantly lower than those in the T2DM uncomplicated with CAS plaque group(P＜0.05);there was no significant difference in gender,proportion of patients com-bined with hyperlipidemia,proportion of smoking history,proportion of drinking history,and the levels of DBP,BMI,NC,PLT,TC,HDL-C,LDL-C,FBG,HbA1c between the T2DM uncomplicated with CAS plaque group and T2DM complicated with CAS plaque group(P＞0.05).The age,proportion of patients combined with hypertension,course of T2DM,SBP,PLR,and NLR of patients in group B,group C,and group D were significantly higher than that in group A,while LC level was significantly lower than that in group A(P＜0.05).The TG level of patients in group D was significantly lower than those in group A(P＜0.05);there was no statistically significant difference in TG level of patients among group A,group B,and group C(P＞0.05).The age,proportion of patients combined with hypertension,and course of T2DM of patients in group C and group D were significantly higher than those in group B,while the SBP of patients in group D was significantly higher than that in group B(P＜0.05);there was no statistically significant difference in SBP of patients between group C and group B(P＞0.05).The age,proportion of patients combined with hypertension,course of T2DM,and SBP of patients in group D were significantly higher than those in group C(P＜0.05).There was no statistically significant difference in the levels of LC,TG,and PLR of patients among group B,group C,and group D(P＞0.05).The NLR of patients in group D was significantly higher than that in group B(P＜0.05);there was no statistically significant difference in NLR of patients between group C and group B(P＞0.05),and there was no statistically significant difference in NLR of patients between group D and group C(P＞0.05).The detection rate of CAS plaques of patients in P1 group,P2 group,P3 group,and P4 group showed a significant increase trend(x2=30.610,P=0.000);and the detection rate of CAS plaques of patients in N1 group,N2 group,N3 group,and N4 group showed a significant increase trend(x2=35.170,P=0.000).Multivariate logistic regression analysis showed that age,PLR,and NLR were independent risk factors for T2DM complicated with CAS plaque(odds ratio=1.107,1.017,1.940;P＜0.05).The opti-mal cutoff value of PLR in predicting T2DM complicated with CAS plaque was 119.95,with an area under the curve of 0.680,a sensitivity of 54.7％,and a specificity of 76.3％;the optimal cutoff value of NLR in predicting T2DM complicated with CAS plaque was 1.97,with an area under the curve of 0.698,a sensitivity of 56.5％,and a specificity of 79.6％.Conclusion PLR and NLR are associated with T2DM complicated with CAS plaque,which are independent risk factors for T2DM compli-cated with CAS plaque,and have certain predictive value for T2DM complicated with CAS plaque.