Model of functional performance in obese elderly people with chronic obstructive pulmonary disease

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).

A model of functional performance was proposed using a multidimensional framework as expounded by Leidy, and incorporating Wilson and Cleary'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.

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.

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.

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.