Weighing the evidence for pharmacological treatment interventions in mild COPD; a narrative perspective

Respiratory Research

Table 1 Studies reporting symptom burden, health status, exacerbations and HCRU in patients with mild COPD^a

Study	Population	Relevant outcome measure(s)	Finding in mild COPD versus controls
Symptom burden and health status studies
Vaz Fragoso et al. 2016 [28]	Smokers with/without COPD (COPDGene cohort)	mMRC, SGRQ	Worse dyspnoea and HRQoL
Bridevaux et al. 2008 [29]	Never smokers or current and former smokers with COPD (SAPALDIA cohort)	SF-36	Worse HRQoL
Exacerbations and HCRU outcomes
Dransfield et al. 2017 [30]	Smokers with/without COPD (COPDGene cohort)	Exacerbations, FEV₁ decline	Exacerbations in mild COPD associated with greater FEV₁ loss versus GOLD 0/2/3/4; exacerbation rate was similar for mild COPD versus GOLD 0 controls
Lee et al. 2016 [31]	COPD	Exacerbations	Lower exacerbation rate in mild COPD^b (0.4) versus GOLD 3/4 (0.9)
Garcia-Aymerich et al. 2011 [32]	Participants from CHS and ARIC cohorts with/without COPD	Hospitalisations due to COPD	Increased hospitalisation risk in mild COPD (adjusted IRR 2.1 and 3.2) versus controls
de Marco et al. 2004 [9]	Younger adults (20–44 years) from the ECRHS cohort with/without COPD	Patient-reported HCRU^c	Greater HCRU in participants with COPD (all stages including stage 0) versus controls

Of the results identified by the search terms stated, only relevant, original studies including a mild or undiagnosed COPD population are shown. ARIC: Atherosclerosis Risk in Communities; CHS: Cardiovascular Health Study; COPD: chronic obstructive pulmonary disease; ECRHS: European Community Respiratory Health Survey; FEV₁: forced expiratory volume in 1 s; GOLD: Global Initiative for Chronic Obstructive Lung Disease; HCRU: healthcare resource utilisation; HLQ: health and labour questionnaire; HRQoL: health-related quality of life; IRR: incidence rate ratio; mMRC: modified Medical Research Council Dyspnea Scale; SF-36: 36-item Short-Form Survey; SGRQ: St George’s Respiratory Questionnaire; SAPALDIA: Swiss Study on Air Pollution and Lung Diseases in Adults. ^amild COPD defined as GOLD 0 and/or 1 COPD, unless otherwise stated.^bmild COPD defined as GOLD stage 1 and 2. ^cincluding medication use, doctor visits and hospitalisations due to COPD

ISSN: 1465-993X