Dyspnea refers to a subjective sensation of breathing
discomfort.1 In a study involving a community-based
population aged > 70 years, the prevalence of dyspnea
was found to be 32%.2 Dyspnea can lead to limitations in
daily activities, reduced exercise tolerance, and
heightened mortality risks.3
Dyspnea not only affects individuals with diagnosed
respiratory conditions but also poses a signiﬁcant
burden on those with undiagnosed conditions. In a
systematic review by Müller et al,4 the combined
prevalence of dyspnea in the adult general population
across 11 studies was estimated to be 10%. Dyspnea can
arise from a broad spectrum of underlying factors,
including both respiratory and nonrespiratory
conditions. Studies have revealed that dyspnea is not
solely attributable to respiratory conditions but is also
heavily inﬂuenced by cardiovascular deconditioning and
by nonrespiratory factors, including psychosocial, social,
and environmental determinants.5,6
Dyspnea is a prevalent symptom with consequences that
extend beyond its physiologic implications. A study in
European patients with COPD explored the burden of
dyspnea and identiﬁed potential correlates. The study
revealed that higher dyspnea impact correlated with
lower health-related quality of life, increased work
impairment, and a higher frequency of emergency
department visits.7
The three objectives of our study were as follows: (1) to
evaluate the impact of dyspnea in adults from the
general population who had no prior diagnosis of
respiratory disease but who reported having signiﬁcant
respiratory symptoms in the past 6 months; (2) to
identify associated risk factors for dyspnea and estimate
their inﬂuence on the symptom; and (3) to explore the
relationship between dyspnea and health care utilization,
quality of life, and work productivity in adults with
undiagnosed respiratory symptoms.
Study Design and Methods
Recruitment of Undiagnosed Cases and Healthy
Control Patients
Between June 2017 and January 2023, adults aged$ 18
years were recruited through a two-step process into the
Undiagnosed COPD and Asthma Population (UCAP)
study, a multicenter caseﬁnding study. Approval for
the study was obtained from the research ethics boards
of the 17 participating study sites across Canada.
Informed, written consent was provided by all study
participants.
Both landlines and cellphones within a 90-minute radius
of any of the 17 study sites were dialed randomly. A
Take-home Points
Study Question: How profoundly are adults with
undiagnosed respiratory symptoms affected by
dyspnea?
Results: In community-based adults with undiag-
nosed respiratory symptoms, those identiﬁed with
preserved ratio impaired spirometry experienced the
greatest impact of dyspnea, followed by those with
undiagnosed asthma or COPD. Greater dyspnea
impact was associated with increased health care
utilization, lower quality of life, and reduced work
productivity.
Interpretation: Dyspnea imposes burdens on the
health care system and is associated with impaired
quality of life and work productivity.
ABBREVIATIONS: ASQ = Asthma Screening Questionnaire; BD =
bronchodilator; CAT = COPD Assessment Test; PCA = principal
component analysis; PRISm = preserved ratio impaired spirometry;
SGRQ = St. George’s Respiratory Questionnaire
AFFILIATIONS: From The Ottawa Hospital Research Institute (J. B., E.
G., K. L. V., G. G. A., S. M., and S. D. A.), University of Ottawa,
Ottawa, ON; the Desautels Faculty of Management (G. A. W.), McGill
University, Montreal, QC; the Department of Medicine (C. B.), The
University of British Columbia, Vancouver, BC; the Centre de
recherche (L.-P. B. and A. C.), Institut de cardiologie et de pneumo-
logie de Québec, Université Laval, Quebec, QC; the Cumming School
of Medicine (S. K. F.), University of Calgary, Calgary, AB; the
Department of Medicine (E. P.), University of Saskatchewan, Regina,
SK; the Firestone Institute for Respiratory Health (R. A. M.), McMaster