Abstract S58 Table 1

General CART modelling for detecting moderate-severe COPD*

Prediction variables	Risk status	Definition of group	% population	% cases	Risk
Test sample results
Questionnaire data only	High	Reports doctor-diagnosed COPD/emphysema or any dyspnoea or smoking >20 years	54.3	87.2	13.0
Questionnaire data only	Low	Rest of the sample	45.7	12.8	2.3
Prebronchodilator PEF and questionnaire data	High	PEF/Ht² ⩽2.2	21.6	83.8	31.4
Prebronchodilator PEF and questionnaire data	Low	PEF/Ht² >2.2	78.4	16.2	1.7
Validation sample results
Questionnaire data only	High	Reports doctor-diagnosed COPD/emphysema or any dyspnoea or smoking >20 years	55.4	87.5	12.6
Questionnaire data only	Low	Rest of the sample	44.6	12.5	2.2
Prebronchodilator PEF and questionnaire data	High	PEF/Ht² ⩽2.2	21.8	83.9	30.7
Prebronchodilator PEF and questionnaire data	Low	PEF/Ht² >2.2	78.2	16.1	1.6

Forced expiratory volume in 1 5 (FEV₁) <80% predicted.
*Postbronchodilator FEV₁/FVC <LLN.
CART, classification and regression tree modelling; COPD, chronic obstructive pulmonary disease; FVC, forced vital capacity; LLN, lower limit of normal; PEF, peak expiratory flow.