Age-Related Differences in Health-Related Quality of Life in COPD: An Analysis of the COPDGene and SPIROMICS Cohorts

Abstract

Objective: Younger persons with COPD report worse health-related quality of life (HRQL) than do older individuals. The factors explaining these differences remain unclear. The objective of this article was to explore factors associated with age-related differences in HRQL in COPD.

Methods: Cross-sectional analysis of participants with COPD, any Global Initiative for Chronic Obstructive Lung Disease grade of airflow limitation, and ≥ 50 years old in two cohorts: the Genetic Epidemiology of COPD (COPDGene) study and the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS). We compared St. George's Respiratory Questionnaire (SGRQ) scores by age group: middle-aged (age, 50-64) vs older (age, 65-80) adults. We used multivariate linear modeling to test associations of age with HRQL, adjusting for demographic and clinical characteristics and comorbidities.

Results: Among 4,097 participants in the COPDGene study (2,170 middle-aged and 1,927 older adults) SGRQ total scores were higher (worse) among middle-aged (mean difference, -4.2 points; 95% CI, -5.7 to -2.6; P < .001) than older adults. Age had a statistically significant interaction with dyspnea (P < .001). Greater dyspnea severity (modified Medical Research Council ≥ 2, compared with 0-1) had a stronger association with SGRQ score among middle-aged (β, 24.6; 95% CI, 23.2-25.9) than older-adult (β, 21.0; 95% CI, 19.6-22.3) participants. In analyses using SGRQ as outcome in 1,522 participants in SPIROMICS (598 middle-aged and 924 older adults), we found similar associations, confirming that for the same severity of dyspnea there is a stronger association with HRQL among younger individuals.

Conclusions: Age-related differences in HRQL may be explained by a higher impact of dyspnea among younger subjects with COPD.

Trial registry: ClinicalTrials.gov; No.: NCT00608764 and No.: NCT01969344; URL: www.clinicaltrials.gov.

Keywords: COPD; aging; dyspnea; geriatrics; health status; obstructive lung disease; quality of life.

Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

SGRQ total score by age group in each cohort. All differences between middle-aged and older adult groups, in each cohort, are significant at P < .05. The box represents the interquartile range and the central line the median. COPDGene = Genetic Epidemiology of COPD; SGRQ = St. George’s Respiratory Questionnaire; SPIROMICS = Subpopulations and Intermediate Outcome Measures in COPD Study.

Figure 2

Average effect of different degrees of dyspnea on SGRQ total score by age group among participants in the Genetic Epidemiology of COPD study. mMRC = modified Medical Research Council. See Figure 1 legend for expansion of other abbreviation.

Figure 3

Average effect of different degrees of dyspnea on SGRQ total score by age group among participants in the Subpopulations and Intermediate Outcome Measures in COPD Study. See Figure 1 and 2 legends for expansion of abbreviations.