Standardized questionnaires can effectively be used to help diagnose chronic obstructive pulmonary disease (COPD) in settings where healthcare resources may be limited, according to a new study.
The study, “Discriminative Accuracy of Chronic Obstructive Pulmonary Disease Screening Instruments in 3 Low- and Middle-Income Country Settings,” was published in JAMA.
About 90% of the morbidity and mortality related to COPD affects people who live in low- or middle-income countries where it can be difficult to diagnose and treat COPD, as there is often little or no access to necessary medical equipment or experts.
“It is important from a public health perspective to identify new ways to diagnose and treat COPD in resource limited settings,” Trishul Siddharthan, MD, an assistant professor at the University of Miami Miller School of Medicine and the study’s lead author, said in a press release.
An international team of scientists set out to test the diagnostic accuracy of three questionnaires: the COPD Assessment in Primary Care to Identify Undiagnosed Respiratory Disease and Exacerbation Risk (CAPTURE), the Lung Function Questionnaire (LFQ), and the COPD in LMICs Assessment (COLA-6) tool. All of these tools evaluate COPD-like symptoms on numerical scales, with higher scores indicating a higher disease risk, except for the LFQ.
These questionnaires were used to screen patients in three different settings: urban Lima in Peru, semi-urban Bhaktapur in Nepal, and rural Nakaseke in Uganda. Patients also underwent spirometry testing — a set of standard lung function tests — to assess the presence of COPD.
“Using simple tools to screen for COPD, or to identify people who need to go on to have confirmatory spirometry, would be a significant step to reducing the underdiagnosis of COPD in [low- or middle-income countries] while providing more effective use of available resources,” the researchers wrote.
A total of 10,709 people participated in the study across the three sites. Half of the participants were women, about a third had a history of smoking cigarettes, and all were 40 or older.
COPD rates based on spirometry measures were 17.7% in Bhaktapur, Nepal; 2.6% in Lima, Peru; and 6.9% in Nakaseke, Uganda. Overall, just under 10% of the people in the analysis had COPD, and just under half (49.4%) of COPD patients had clinically relevant disease.
Compared with those without disease, COPD patients were on average significantly older (62.5 vs. 55.6 years), more likely to be men (59.2% vs. 48.8%), and more commonly had a history of tobacco use (50.5% vs. 33.2%). COPD patients also tended to report poorer quality of life.
For each of the three questionnaires (CAPTURE, COLA-6, and LFQ), researchers calculated the area under the receiver operating characteristic curve, or AUC. Put simply, AUC is a statistical measure of how well a test can tell the difference between two things — in this case, having COPD or not. AUC values can range from 0.5 to 1, with values closer to 1 indicating a better ability to distinguish.
After statistical adjustments, AUCs for each questionnaire ranged from 0.717, for the LFQ in Peru, to 0.791, for COLA-6 in Nepal. Overall, these values reflect a fairly good diagnostic ability, according to researchers.
“COPD morbidity and screening test performance varied by site, emphasizing that the utility of these tools is context dependent,” the researchers wrote.
“Understanding local COPD prevalence and severity is crucial in determining whether the use of any of the screening strategies can be justified,” they wrote. “Even within countries there will be significant differences, including urban-rural disparities in COPD prevalence and access to diagnostics and treatment.”
The team also noted that, on average, each of the questionnaires took less than 10 minutes to complete, and were almost always completed fully.
“The 3 screening instruments evaluated in this study were feasible to deliver based on time-to-use by field researchers and completeness of data,” the researchers wrote.
Siddharthan added: “We found that screening instruments are easy to deliver and have reasonable sensitivity in ruling out the disease. The screenings can be feasibly delivered in low- and middle-income settings by lay community workers.”
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