A screening questionnaire was able to identify “clinically significant” chronic obstructive pulmonary disease (COPD) in more than 40% of undiagnosed adults with the disease at that level taking part in a clinical trial, a recent study reported.
Although further changes to the COPD Assessment in Primary Care to Identify Undiagnosed Respiratory Disease & Exacerbation Risk (CAPTURE) questionnaire would improve its sensitivity in detecting COPD cases, the tool has the potential to be helpful in identifying people in primary care who would benefit from a COPD test.
“CAPTURE was designed to be easy for physicians to use. The screening is simple, takes less than a minute, and helps identify adults with trouble breathing who should be evaluated further,” Antonello Punturieri, MD PhD, program director of the Chronic Obstructive Pulmonary Disease/Environment Program at the National Heart, Lung, and Blood Institute (NHLBI), said in a National Institutes of Health press release.
“The goal with trying to find COPD is to treat it earlier, which will … hopefully prevent their disease from progressing,” added Fernando J. Martinez, MD, a principal study investigator and chief of the Pulmonary and Critical Care Medicine division at Weill Cornell Medicine in New York.
The study, “Discriminative Accuracy of the CAPTURE Tool for Identifying Chronic Obstructive Pulmonary Disease in US Primary Care Settings,” was published in JAMA.
Goal is easy and low-cost start to more definitive COPD diagnosis
Nearly 16 million people in the U.S. are diagnosed with COPD, but the actual number could be higher as many are unaware of having the condition, a government agency reports.
One reason is that COPD symptoms, which can include persistent coughing, shortness of breath, wheezing, and chest pain, might not be evident or specific enough for a diagnosis. Another is the underuse of spirometry, the gold standard for assessing lung function and diagnosing COPD, in primary care settings.
CAPTURE, developed with NHLBI support, is intended for use during primary care visits to help doctors identify patients with severe enough COPD to benefit from treatment.
Screening with CAPTURE starts with five questions to assess a person’s exposure to smoke or air pollution, breathing problems, fatigue, and acute (within past year) respiratory illnesses. The questionnaire is scored from zero to six, and those with scores of five or six are immediately flagged for further testing.
People with medium scores — two to four — are guided to take a peak expiratory flow rate breathing test, which checks lung health by measuring how much air they can forcefully exhale and how quickly. Test results lower than 250 L/min for women and 350 L/min for men also flag a person for further COPD testing.
The CAPTURE questionnaire was among a group of similar low-cost diagnostic tools tested previously in countries with limited access to necessary medical equipment or expertise.
To assess how well the full CAPTURE tool works, researchers in the U.S. designed a multicenter clinical trial (NCT03581227) to evaluate its sensitivity (ability to accurately detect COPD) and specificity (ability to identify those without COPD) during primary care visits by adults, ages 45 to 80, without a COPD diagnosis.
Their trial enrolled 4,325 people, 63% women, with at least one visit to any of 100 participating primary care centers between Oct. 12, 2018, and April 1, 2022. Participants’ mean age was 61.6, half were obese (49.9%) by body-mass index measures, 18.3% had asthma or used inhaled respiratory medications, and 44.6% had smoked at least one cigarette at some point, while 13.2% reported being current smokers.
Participants were assessed using CAPTURE during their visit and then underwent spirometry analysis for a more definitive diagnosis. Clinically significant, meaning moderate or severe, COPD was diagnosed on the basis of the forced expiratory volume (FEV1) and the FEV1 and forced vital capacity (FVC) ratio, both common measures of lung function. FEV1 measures how much air a person can forcibly exhale in one second, while FVC measures the total amount of air exhaled during that test.
233 of 532 people flagged for moderate-to-severe COPD via questionnaire
The CAPTURE questionnaire — with or without the additional peak expiratory flow rate test — identified 532 (12.3%) participants as positive for clinically significant COPD, including 233 (43.8%) based on questionnaire scores of five or six. Of 110 people (2.5%) with clinically significant COPD diagnosed through spirometry tests, 53 had been flagged by CAPTURE as possible COPD patients. In this group, the screening tool showed a sensitivity of 48.2% (correctly identified COPD cases), and a specificity of 88.6%, incorrectly identifying 11.4% as having COPD.
“Patients with a positive screening result for clinically significant COPD were significantly more likely … than patients with a negative screening result to have asthma or use daily inhaled respiratory medications (43.6% vs 14.8%, respectively), currently smoke (25.1% vs 11.5%), have COPD Assessment Test scores of 10 or greater (77.3% vs 30.6%), and report 1 or more respiratory illnesses within the prior 12 months (24.7% vs 7.2%),” the researchers reported.
Among those with a positive screening results but not clinically significant COPD, 10.2% had mild disease.
“There is a high degree of respiratory burden in primary care, and physicians need to ask about it and do the appropriate testing to determine if symptoms are driven by COPD or another process so that patients can get the right treatment,” said MeiLan K. Han, MD, a principal study investigator and professor of medicine in the Division of Pulmonary and Critical Care at the University of Michigan at Ann Arbor.
“Within this US primary care population, the CAPTURE screening tool had a low sensitivity but a high specificity for identifying clinically significant COPD,” the researchers concluded, and further optimization is needed.
Optimization possibilities include alterations to the approach and composition of its questions and to the definition of clinically significant COPD used to develop the tool. Such changes, the research team noted, need to maintain a balance between sensitivity and specificity, and retain the simplicity needed for CAPTURE to be easily used in primary care.