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

Abstract

Background: 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. Objectives: 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. Patients and Methods: 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. Results: 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. Conclusions: 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.