A new diagnostic tool for identifying individuals with undiagnosed asthma and/or chronic obstructive pulmonary disease (COPD) was recently developed. The study findings forming the basis for the creation of this tool, the Undiagnosed COPD and Asthma Population Questionnaire (UCAP-Q), were recently published in the European Respiratory Journal.

Although more than 500,000,000 people around the world have been diagnosed with chronic respiratory diseases (largely including asthma and COPD), research has indicated that this may be a significant underestimate, noted study authors. To detect undiagnosed cases of these diseases in which patients’ symptoms may have gone unnoticed or unreported, the US Preventive Services Task Force has encouraged an active case-finding approach rather than spirometry screening.

Because existing case-finding instruments for COPD and asthma, including the COPD Diagnostic Questionnaire (COPD-DQ) and the Asthma Screening Questionnaire (ASQ), have notable limitations, study authors decided to develop a new case-finding tool that could be used for both asthma and COPD. “Combining asthma and COPD detection into a single instrument is worthwhile, because despite their distinct pathophysiological differences, they present with the same symptoms (ie, dyspnea, wheeze, cough, and mucus production) and health care providers often have trouble distinguishing one condition from the other upon initial presentation,” the researchers noted.


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The investigators conducted 2 prospective, multicenter, cohort studies. The derivation study included a cohort of 1615 adult participants with no prior diagnosis of lung disease who experienced at least 1 respiratory symptom (eg, shortness of breath, prolonged coughing, wheezing, or increased mucus or sputum). Participants were randomly recruited by phone from 16 Canadian sites between June 2017 and March 2020. Asthma and COPD were confirmed via pre- and post-bronchodilator spirometry, said study authors, who then developed predictive questions via multinomial logistic regression with backward elimination. The 13-item UCAP-Q was subsequently developed with 92% sensitivity for asthma and 97% sensitivity for COPD, specificity of 17%, with an area under the curve (AUC) of 0.69 (95% CI, 0.64-0.74) for asthma and 0.82 (95% CI, 0.78-0.86) for COPD, said study authors.

The researchers then prospectively validated the questionnaire with another group of participants (ie, the validation cohort), which was selected in the same random manner as the derivation cohort between October 2020 and September 2021. The 471 validation cohort participants completed the UCAP-Q, COPD-DQ, and the ASQ. Those who scored at least 20 points on the COPD-DQ, more than 6 on the ASQ, or whose UCAP-Q responses indicated a 6% or higher probability of asthma or COPD underwent spirometry testing to confirm asthma and or COPD. Study authors’ analysis of validation cohort data for the UCAP-Q revealed sensitivities of 93% for asthma and 92% for COPD, specificity of 19%, with AUC’s of 0.70 (95% CI, 0.62-0.79) for asthma and 0.81 (95% CI, 0.74-0.87) for COPD.

Upon further comparative analysis of validation cohort data for the UCAP-Q, COPD-Q, and ASQ, study investigators found that the UCAP-Q predicted an asthma diagnosis with higher sensitivity than the ASQ/COPD-DQ (93% vs 76% sensitivity, respectively), and that “sensitivity for prediction of undiagnosed COPD (92%) was identical between the questionnaires.” Study authors further noted that the “AUC’s for UCAP-Q were higher compared to AUC’s for currently recommended case-finding questionnaires for asthma or COPD.”

The researchers concluded UCAP-Q “is reliable and sensitive in detecting undiagnosed cases of asthma or COPD, which should then be confirmed with spirometry.” Study limitations include: 1) the UCAP-Q is unvalidated in asymptomatic individuals; 2) some participants did not receive bronchial challenge tests; 3) contact bias; and 4) lack of ethnic diversity in the study cohorts.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

Reference

Huynh C, Whitmore GA, Vandemheen KL, et al. Derivation and validation of the UCAP-Q case-finding questionnaire to detect undiagnosed asthma and COPD. Eur Respir J. Published online March 24, 2022. doi:10.1183/13993003.03243-2021