Table 2

Overview of baseline variables included in the study

Variable	Variable type	Values	Register used
Sociodemographic variables
Age	Continuous		CRS
Sex	Categorical, binary	1=Female 2=Male	CRS
Cohabitation status	Categorical, binary	1=Living alone 2=Cohabiting	DST
Health status variables
Comorbidity, CCI	Count		DNPR
BMI	Continuous		DrKOL
Smoking status	Categorical	0=Non-smoker 1=Former smoker 2=Current smoker	DrKOL
MRC dyspnoea scale	Categorical, ordinal	Range: 1–5	DrKOL
FEV₁ % of expected	Continuous		DrKOL
Former asthma diagnosis	Categorical, binary	0=No 1=Yes	DNPR
Medication at baseline	Categorical	0=No medication 1=LAMA 2=LABA 3=LABA+ICS 4=LABA+LAMA 5=LABA+LAMA+ICS
No of moderate pneumonias	Count		NPR
No of severe pneumonias	Count		DNPR
No of moderate non-pneumonic exacerbations	Count		NPR
No of severe non-pneumonic exacerbations	Count		DNPR

BMI, body mass index; CCI, Charlson Comorbidity Index; CRS, Civil Registration System; DNPR, Danish National Patient Register; DrKOL, Danish Register for Chronic Obstructive Pulmonary Disease; DST, Statistics Denmark; FEV₁, forced expiratory volume in 1 s; ICS, inhaled corticosteroid; LABA, long-acting beta-agonist; LAMA, long-acting muscarinic antagonist; MRC, Medical Research Council; MRC, Medical Research Council.