Model of Functional Performance in Obese Elderly People With Chronic Obstructive Pulmonary Disease

AbstractPurpose: To test a theoretically and empirically supported model of the relationships among percent truncal fat (truncal obesity); disease severity (carbon monoxide diffusing capacity [DLCO]); symptoms (dyspnea); functional capacity (6-min walk test distance); and functional performance (functional performance index) of elderly people with chronic obstructive pulmonary disease (COPD).Design and Method: A model of functional performance was proposed us* ing a multidimensional framework as expounded by Leidy, and incorporating Wilson and Geary's model for the relationship between symptoms and functional status. Path analysis was used to examine the relationships among variables. The researchers used a descriptive, cross- sectional design. Subjects were phone screened and completed electrocardiography, physical examination, spirometry testing, and a 4-min walk test as part of initial screening. Enrolled subjects completed a whole-body dual-energy x-ray absorptiometry scan to measure truncal obesity, 6-min walk test, upper body functional performance test, and questionnaires. Subjects were grouped into normal weight, overweight, or obese according to body mass index.Results: The sample consisted of 76 people 55 years of age and older with mild to severe COPD. Percent truncal fat (truncal obesity) did not affect functional performance directly, but did affect it indirectly through dyspnea. The 6-min walk test distance, dyspnea, and DLCO accounted for 29% of the variability in functional performance.Conclusions: We believe that the effectiveness of pulmonary rehabilitation will be enhanced when nurses consider weight loss as a controllable factor for overweight and obese clients. The increasing prevalence of obesity in this population may dictate collaboration between dieticians and pulmonary rehabilitation nurses for effective rehabilitation programs.Clinical Relevance: These findings suggest that percent truncal fat (truncal obesity) may be an indirect factor in the performance of daily activities of people with COPD. We anticipate that clinicians will use knowledge derived from this study to develop interventions to reduce or minimize truncal fat (truncal obesity) and its effects on people with COPD.Key wordsObesity, chronic obstructive pulmonary disease, functional performance, elderly, modelChronic obstructive pulmonary disease (COPD) is the fourth-leading cause of chronic morbidity and mortality in the United States and is projected to rank fifth worldwide in 2020 as burden of disease according to the World Health Organization (WHO; WHO Global Initiative for Chronic Obstructive Lung Disease, 2006). Annual prevalence of obesity among U.S. adults 20 years of age and older has increased from 22.9% in 1994 to 32.2% in 2004. The prevalence is about 23% in adults 60 years of age and older (Centers for Disease Control and Prevention [CDC], 2007). When patients with COPD present with obesity as a comorbid condition, or vice versa, their morbidity and mortality risks are increased because obesity has been found to alter pulmonary function and diminish exercise capacity by its adverse effect on respiratory mechanics, resistance, and respiratory muscle function (Jordan & Mann, 2010).Presently, there is no cure for COPD, and therapy is aimed at reducing symptoms and improving function to improve quality of life (QoL). Functional status, according to Leidy's (1994) framework, is broadly conceptualized to include four dimensions: functional capacity, functional performance, functional reserve, and functional capacity utilization. This study focused on functional performance and functional capacity in relation to the model development.Older adults have more fat mass around their trunk, leading to increased waist circumference (Hughes et al., 2004); an area of major interest is to what extent abdominal fat has affected the work of breathing in the already compromised lungs of the COPD patient. …