Spearman’s r for correlations between days of lost productivity and age, FEV1% predicted values, comorbidities and exacerbations of respiratory symptoms in hospital-recruited COPD cases, population recruited-COPD cases and population-recruited control subjects
| Age | FEV1, % of predicted | Number of comorbid conditions | Number of events, exacerbations of respiratory symptoms | |
|---|---|---|---|---|
| Hospital-recruited COPD cases, Spearman’s r | r=0.154; p=0.12 | r=−0.390; p<0.001 | r=0.341; p<0.001 | r=0.071; p=0.478 |
| Population-recruited COPD cases, Spearman’s r | r=0.035; p=0.80 | r=−0.214; p=0.124 | r=0.28; p=0.039 | r=0.246; p=0.075 |
| Population-recruited controls, Spearman’s r | r=0.023; p=0.81 | r=−0.136; p=0.163 | r=0.156, p=0.108 | r=0.20, p=0.038 |
The significance of bold is P<0.05.
COPD, here defined by FEV1/FVC<0.7 postbronchodilation and FEV1 <80% of predicted values.
COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity.