Evaluation of the functional status of patients with chronic obstructive pulmonary disease via the modeling approach

Background: Chronic obstructive pulmonary disease (COPD) is common worldwide. COPD has negative effects on the quality of life of the patient due to restrictions on daily activities. It can cause a major healthcare burden according to the stage and grade of disease. Objective: The purpose of this study was to determine the physical and psychological functional capacity factors affecting patients' functional performance and to develop a COPD-specific functional status model using these factors. Methods: A group of randomly selected patients (n=183) diagnosed with COPD at a university hospital in Turkey comprised the study sample. Physical examinations were carried out on all patients and they completed questionnaires that included socio demographic and disease characteristics, the Hospital Anxiety and Depression Scale, Functional Performance Inventory and Short Form-36 Survey. The proposed theoretical model was analyzed in the LISREL program using the structural equation modeling approach. Results: We found that the independent latent variable of the physiological functional capacity yielded a significant positive effect on the dependent latent variable of functional performance, while the psychological functional capacity produced no significant effect. Conclusions: The COPD-specific functional status model should prove to be an effective and beneficial tool for issues such as treatment maintenance and for the preservation or improvement of patients' quality of life.