Abstract
The research group of the Type A Behavior Pattern Conference, Japan has developed a 122-item questionnaire called Japanese Coronary-prone Behavior Scale (JCBS) which assesses Japanese mentality, habits and daily behaviors as well as type A behavior pattern (TABP). In a previous study of the responses to the JCBS in 292 patients undergoing coronary angiography (CAG), we have proposed a 26-item subscale of the JCBS (Scale A) which discriminated patients with significant (≥75%) coronary stenosis from those without such stenosis with a total error count of 22%. In the present study, we examined if the Scale A predicts the presence of coronary stenosis among an independent group of patients.
The JCBS was administered to newly collected 158 male patients undergoing CAG (age, 57±9 years); 54 (35%) of them were patients with acute myocardial infarction (MI), 31 (20%) had a history of MI, and 20 (13%) had a history of percutaneous transluminal coronary angioplasty (PTCA). According to the CAG, 106 patients (67%) had significant (≥75%) coronary stenosis in at least one major coronary artery or branch (group CS+) and 52 had no such stenosis (group CS−). According to the discriminant score calculated by applying the previously defined canonical discriminant function on the responses to Scale A items, the patients were classified into two groups by the likelihood to have coronary stenosis.
The discriminant score of the Scale A predicted correctly the absence of coronary stenosis in 65% of group CS− patients and the presence of coronary stenosis in 71% of groups CS+ patients (total error count = 32% and χ2=18.8, P<0.001). Among 54 patients with acute MI, 10 patients belonged to group CS−. These patients showed a tendency to have a greater discriminant score than the rest of the patients in group CS- (P=0.082), while no such difference was observed between patients with and without acute MI in group CS+. None of the patients in group CS- had a history of MI or PTCA. In group CS+, there was no difference in the discriminant score between patients with and without previous MI or between those with and without a history of PTCA.
The results of this study indicate the validity of the JCBS Scale A as a predictor of significant coronary stenosis among male patients undergone CAG. Although several questionnaires have been reported in earlier studies to predict coronary artery disease, most of them have aimed to assess TABP. The Scale A is unique from these scales in that it assesses the behavioral characteristics which are not restricted in the concept of TABP. In this aspect, the Scale A seems to be a valuable measure of the characteristics of coronary-prone behavior among Japanese. Additionally, the discriminant score of the Scale A tended to be higher in patients with acute MI but having no significant coronary stenosis, suggesting that this scale may be also associated with the process of coronary artery obstruction by thrombus formation or vasospasm. To clarify the potential values of the JCBS Scale A, further studies are necessary on its associations with various features of coronary artery disease in wider ranges of population.
