Prediction of Quality of Life by Type D Personality and Illness Perception Factors in Patients With Coronary Artery Disease: A Structural Equation Model

Coronary artery disease (CAD) is a common cause of death and disability, with the mortality incidence of 167 per 100,000 people. The Known physical cause of coronary heart disease (CHD) can predict only 50% of CHD incidence. Recently, health psychologists pay attention to the key role of nonbiological factors such as psychological factors in CHD. The aim of this study was to examine the direct and indirect relationships between type D personality and quality of life in CHD patients and create a conceptual model. In this cross- sectional study, 99 CAD patients were finally selected from the patients referred to the angiography unit of Mostafa- KHomeini Hospital in Tehran, Iran, from April to June 2012. The questionnaires used to gather data were type D personality scale, quality of life scale and illness perception scale. To design the model, we used analysis of Moment Structures (AMOS) software because the suggested model was a kind of structural equation models. Ninety-nine CHD patients, with the mean age of 59.7 years (age range, 20 - 86) were studied and 58.8% of them were males. Cronbach’s alpha for quality of life and type D personality questionnaires were calculated 0.93 and 0.81, respectively. Forty-eight significant parameters estimated in the model that is fitted with the chi-square = 67.905, degrees of freedom = 57 and P-value = 0.153. The type D personality was related to quality of life in patients with CHD directly or indirectly by a mediator of the perception of illness. Diagnosing type D personality and knowing about the effect of these perceptions can help physician to identify patients with prone personality and prevent them from the disease by changing their lifestyle