Table 5– Multivariate analysis of physical activity (PA) changes and health-related quality of life (HRQoL) changes from baseline to 5-yr follow-up adjusted by relevant variables

Level of PA baseline/5 yrs	Model 1: total SGRQ score		Model 2: total CRQ score
Level of PA baseline/5 yrs	β-estimate	p-value	β-estimate	p-value
Low/low	Reference		Reference
Low/moderate-high	15.9	0.0005	8.7	0.05
Moderate/low	-0.7	0.87	2.6	0.56
Moderate/moderate	10.2	0.007	10.3	0.005
Moderate/high	18.4	<0.0001	14.8	0.0004
High/moderate-low	8	0.05	10.7	0.005
High/high	16.9	<0.0001	13.6	0.0003

SGRQ: St George’s Respiratory Questionnaire; CRQ: Chronic Respiratory Questionnaire. Positive values indicate an improvement in HRQoL, negative values indicate a decline in HRQoL. SGRQ score improvements have been changed to positive values and impairment has been changed to negative values. Multivariate models where the dependent variables were the change in the total SGRQ score (model 1) and the total CRQ score (model 2) from baseline to 5 yrs. The main independent variable in model 1 was the change in PA over the 5-yr period, adjusted by age, dyspnoea, forced expiratory volume in 1 s (% pred), hospital admissions for chronic obstructive pulmonary disease (COPD) exacerbations in the 2 yrs prior to enrolment, comorbidities and mental health status (measured by the short form (SF)-36 Mental Component Summary Scale (MCSS1)) at baseline, as well as by baseline HRQoL measured by the total SGRQ score. The main independent variable in model 2 was the change in PA over the 5-yr study period adjusted by hospital admissions for COPD exacerbations in the 2 yrs prior to enrolment and baseline mental health status (measured by the SF-36 MCSS1), as well as by the baseline HRQoL levels at the beginning of the study measured by the total CRQ score. The reference group for comparison in both models were those who had a low level of PA at the beginning and also at 5 yrs of follow-up.