The Establishment And Evaluation Of The Diagnostic Scoring System For Coronary Artery Disease In Patients With Diabetic Foot

Diabetic foot(DF) is the ulcer or gangrene of the foot or lower limb that caused by vascular lesions, neuropathy and infection of diabetes mullitus(DM), and is the most serious and one of the highest cost of treatment in chronic complications of DM. Coronary artery disease(CAD) is the leading cause of death of DM. DM is combined with silent myocardial ischemia(SMI) easily and atypical angina pectoris, because of autonomic neuropathy and increased endorphins, DF patients prone to sudden death because of SMI, early diagnose and timely treat CAD are particularly important in DF patients. Due to the limitation of movement, the screening examination methods of CAD is relatively limited in DF patients. Current screening methods suitable for CAD such as single-photon emission computed tomography myocardial perfusion(SPECT) and coronary computed tomography angiography(CCTA), which are expensive, so these examinations are not fit for all DF patients without angina pectoris symptoms. These screening methods are suitable for the high risk patients with CAD in patients with DF. Clinical characteristics of DF with CAD are analyzed retrospectively, the risk factors are analyzed for CAD in patients with DF, risk factor scores are assigned according to odds ratio(OR) values,the scoring system for diagnosis of CAD is established, and its application efficiency and accuracy are assessed.The research method included: first, a total of 445 patients with DF from were analyzed retrospectively with a case-control study method.These patients were divided into CAD group(n=372) and control group(n=73) according to the presence or absence of CAD. The general information and clinical indicators were collected, which included gender,age, BMI, smoking, duration of diabetes(year), hypertension, the temperature of foot skin, LVEF, ABI, fasting and 2h postprandial blood glucose, low-density lipoprotein cholesterol, fibrinogen and so on. The clinical differences were analyzed between the two groups. Risk factors were selected from clinical factors examined through multiple logistic regression analysis for CAD in patients with DF. Second, according to the OR value of the risk factors, established the scoring system for diagnosis of CAD in patients with DF. Third, application efficiency of diagnostic scoring system was tested by calculating area under the receiver operating characteristics(ROC) curve. The accuracy of diagnosis scoring system was evaluated through sensitivity, specificity, accuracy, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio.The results in this study included: first, age(OR=2.277, 95%CI :1.366~3.793, P=0.002), male sex(OR=2.473, 95%CI:1.213~5.044,P=0.013), BMI≥25kg·m-2(OR=2.904, 95%CI:1.404~6.008, P=0.004), the duration of diabetes≥10 years(OR=3.220, 95%CI:1.575~6.582, P=0.001),ABI≤0.9(OR=2.438, 95%CI : 1.167 ~ 5.096, P=0.018) and the chronic renal insufficiency(OR=2.876, 95%CI:1.159~7.140, P=0.023) were risk factors for CAD in DF patients. Second, the specific points of diagnostic score scheme for CAD in patients with DF were: age(<50 years=0 point,50~64 years=1 point, ≥65 years=2 points), sex(female=0 point, male=2points), the duration of diabetes(<10 years=0 point, ≥10 years=3 points),ABI( > 0.9=0 point, ≤0.9=2 points), BMI( < 25kg·m-2=0 point,≥25kg·m-2=3 points) and chronic renal insufficiency(absent=0 point,present=3 points). Third, for diagnosis scoring system, the area under the ROC curve was 0.758(0.682~0.835), the standard error was 0.039, the risk score cut-off points for diagnosis of CAD was 7. The sensitivity,specificity, accuracy, positive predictive value, negative predictive value,positive likelihood ratio and negative likelihood ratio of the scoring systemof the derivation cohort were 78.0%, 59.2%, 82.8%, 90.2%, 35.8%, 1.91 and 0.37.The conclusions in the study includes, first, the diagnostic scoring system for CAD in patients with DF is age score+sex score+the duration of diabetes score+ABI score+BMI score+chronic renal insufficiency score.Second, the risk score cut-off points of the scoring system for diagnosis of CAD was 7. When the risk score is ≥7 points, it suggests to make a definite diagnosis of CAD. When the risk score is <7 points, it can make a regular follow-up according to the patient’s condition. Third, the application effectiveness of the diagnosis scoring system is moderate.