Background: Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide and has been the leading cause of death in China. Patients with COPD have significant decrements in their health-related quality of life (HRQL). It is necessary to identify the factors involved in worsening HRQL in order to improve the HRQL of COPD patients. However, evidence from longitudinal studies is limited. The aim of the study was to evaluate the determinants of the deterioration of HRQL in patients with COPD.
Methods: At baseline, a total of 491 patients with stable COPD received comprehensive assessments, including psychosocial and clinical variables, six minutes walk distance (6MWD), dyspnea grade measured by the 5-grade Medical Research Council (MRC) dyspnea scale, anxiety and depression measured by the hospital anxiety and depression scale and HRQL measured by St. George's Respiratory Questionnaire (SGRQ). Patients were then monitored monthly for 12 months to document COPD exacerbations. At the end of the study period, the SGRQ values were reassessed. A 1-year change in SGRQ total score ≥ 4 was defined as a deterioration of the HRQL and as the outcome. A total of 450 patients completed the 12-month follow-up and were analyzed in the present study.
Results: The age (mean ± SD) was (65.0 ± 10.6) years and 68.7% of subjects were men. The deterioration of the HRQL was 26.4%. In multivariate Logistic regression, independent and graded associations were found between the baseline MRC dyspnoea grade and the deterioration of HRQL (P = 0.012), OR 3.03 (95% CI 1.11-8.24) for patients with MRC dyspnoea grade ≥ 4 versus patients with MRC dyspnoea grade = 1. Similarly, the number of exacerbations during the follow-up was independently and gradually increased with the deterioration of HRQL (P < 0.001), OR 3.03 (95% CI 1.9-5.6) for the participants with exacerbations ≥ 3 versus participants with no exacerbation. The 6MWD evaluated by quartiles was negatively associated with the deterioration of HRQL with borderline statistical significance.
Conclusion: MRC dyspnea grade and the number of exacerbations impair the HRQL of patients with COPD.