The effect of health-related quality of life and physical activity on time to first exacerbation in chronic obstructive pulmonary disease patients.

Introduction: It is known that there is a relationship between severe exacerbations of chronic obstructive pulmonary disease(COPD) requiring hospitalization with loss of forced expiratory volume in one second (FEV1), impaired quality of life, and increased mortality. The aim of this study was to investigate factors [health-related quality of life with COPD Assessment Test (CAT), physical activity, FEV1, PaO2] affecting the time to first exacerbation (TTFE) after discharge in patients hospitalized with exacerbation.

Materials and methods: Seventy-five patients who were hospitalized due to COPD acute exacerbation were included in the study and were prospectively monitored. First exacerbation after discharge was recorded. During the first three days of hospitalization, patients were fitted with a pedometer on any of these days; 24-hour step counts were recorded and CAT was administered through face-to-face interviews. Data on age, sex, PaO2, FEV1, and comorbidities were recorded. The median value of the CAT scores of the participants were taken as the cut-off point. High scores were considered as an indicator of poor quality of life. Cox regression models were created for multivariate analyses and hazard ratios (HR) with 95% confidence interval (95% CI) provided.

Result: There was a statistically significant relationship between the TTFE and CAT score (p= 0.001), FEV1 (pred %) (p= 0.02) and PaO2 (p= 0.02). No statistically significant relationship was found between TTFE and the number of steps used as an indicator of physical activity (p= 0.3). In multivariate analysis, age and sex adjusted CAT and PaO2 significantly affected the TTFE (HR= 2.06 CI 95%= 1.17-3.65 and HR= 5.50 CI 95%= 2.09-14.49, respectively) while adjusted FEV1 (pred %) was not significantly affected the TTFE (HR= 1.54 CI 95%= 0.88-2.70).

Conclusions: The results of this study suggest that using CAT may be an easy-to-apply and practical tool to help identify patients with an increased risk of exacerbation. No significant correlation was found with the daily number of steps, which is an easily measurable indicator of physical activity.