• Physiologic, well-being, and coping resource predictors of functional performance in people with chronic obstructive pulmonary disease

      Wall, Mary Patricia; Thomas, Sue Ann, 1947- (2004)
      This cross-sectional study was conducted to examine the relationships among physiologic, well-being, and coping resource variables and their influence on functional performance in community-dwelling people with chronic obstructive pulmonary disease (COPD). The sample consisted of 119 patients (53.8% male, Mage = 68.17 +/- 8.45 years, 99.1% Caucasian). Two physiologic variables (forced expiratory volume in one second converted to a percent of a predicted value that is adjusted for height, age, gender, and race [FEV1%pred] and concomitant medical comorbidity), four well-being variables (depression, anxiety, happiness, and life satisfaction), two coping resource variables (perceived social support and mastery) and gender were proposed as predictors of functional performance. When functional performance was regressed on each proposed predictor individually (controlling for age) all except comorbidity and gender were significant predictors. However, the multiple regression of functional performance in all proposed predictors plus gender simultaneously showed that only depression (beta = -.707, p = .000), FEV1%pred (beta =.242, p =.000), gender (beta = -.189, p =.012), and the control variable of age (beta = -.322, p = .000) were significant predictors. These variables combined to explain 46% of the variance in functional performance. The low tolerance of depression (.411) indicates the possibility of multicollinearity with the other well-being and coping resource variables, although the bivariate correlations did not suggest this. Neither social support nor mastery was a mediator between depression and functional performance. Social support mediated the effects between anxiety and functional status, but mastery did not. Depressed participants reported worse functional performance than did non-depressed participants. Anxious participants reported worse functional performance than did non-anxious participants. Additional analyses showed that depression was a mediator between social support and functional performance, and between mastery and functional performance. Anxiety (beta = .253, p = .001), life satisfaction (beta = .230, p =.004), mastery (beta = -.236, p = .003), and social support (beta = -.152, p = .036) (but neither happiness nor the control variable of age) were significant predictors of depression.