Impact of Dyspnea on Adults With Respiratory Symptoms Without a Defined Diagnosis

Abstract

Background: We investigated dyspnea; its associated risk factors; and its impact on health care utilization, quality of life, and work productivity in adults with undiagnosed respiratory symptoms.

Research question: What is the impact of dyspnea in adults with undiagnosed respiratory symptoms?

Study design and methods: This population-based study included 2,857 adults who were experiencing respiratory symptoms. These individuals had not been previously diagnosed with any lung conditions and were recruited from 17 Canadian centers using random digit dialing. Each participant underwent spirometry testing both before and after using a bronchodilator to determine if they met the diagnostic criteria for COPD, asthma, or preserved ratio impaired spirometry (PRISm), or if their spirometry results were normal. An age-matched control group (n = 231) was similarly recruited using random digit dialing. A dyspnea impact assessment score from 0 to 100 was produced using questions from the COPD Assessment Test and St. George's Respiratory questionnaire.

Results: Individuals with PRISm (n = 172) reported more impactful dyspnea (mean score, 63.0; 95% CI, 59.5-66.4) than those with undiagnosed asthma (n = 265; mean score, 56.6; 95% CI, 53.9-59.3) or undiagnosed COPD (n = 330; mean score, 57.5; 95% CI, 55.1-59.9). All groups reported significantly more impactful dyspnea than the control group (mean score, 13.8; 95% CI, 11.8-15.7). Patient-specific risk factors including age, sex, BMI, smoking, and comorbidities explained 20.6% of the variation in dyspnea. An additional 12.4% of the variation was explained by disease classification and another 1.7% by the severity of lung function impairment assessed with spirometry. After adjusting for age, sex, and BMI, greater dyspnea impact was associated with increased health care utilization, lower quality of life, and reduced work productivity.

Interpretation: Our findings showed that in community-based adults with undiagnosed respiratory symptoms, those identified with PRISm experienced the greatest impact of dyspnea. Dyspnea imposes burdens on the health care system and is associated with impaired quality of life and work productivity.

Keywords: COPD; asthma; case finding; dyspnea.

Figure 1

Study flow diagram demonstrating the case finding and control group recruitment and allocation. ASQ = Asthma Screening Questionnaire; COPD-DQ= COPD Diagnostic Questionnaire; CF = cystic fibrosis; MI = myocardial infarction; PRISM = preserved ratio impaired spirometry.

Figure 2

Box plot demonstrating dyspnea impact according to spirometry disease classification. The center line marks the median. The boxes span the interquartile range (IQR). The outer fences are set at distances 1.5 × IQR from the box. Outliers appear as plotted dots.