Performance of COPD Screening Instruments Assessed in Low, Middle-Income Settings

Trishul Siddharthan, MD

A cross-sectional study into the discriminative accuracy of 3 individual screening tool for chronic obstructive pulmonary disease (COPD) concluded that the instruments were feasible to administer in low- and middle-income settings in Nepal, Peru, and Uganda.

Investigators called for further research into the performance of these instruments in other diverse settings and to determine whether their implementation is associated with improved clinical outcomes.

Trishul Siddharthan, MD, Division of Pulmonary and Critical Care at the Miller School of Medicine, University of Miami, and fellow investigators noted that a majority of recorded history of morbidity and mortality from COPD has been associated with low- and middle-income countries, along with significant economic effects.

The team conducted a multi-country, population-based study to assess the discriminative accuracy of 3 simple COPD screening tools across 3 diverse settings.

The Methods

The cross-sectional analysis of discriminative accuracy was conducted between January 2018 and March 2020 across 3 low- and middle-income settings including semi-urban Bhaktapur, Nepal, urban Lima, Peru, and rural Nakaseke, Uganda.

These sites were selected to evaluate the performance of the 3 featured screening tools that included the COPD Assessment in Primary Care to Identify Undiagnosed Respiratory Disease and Exacerbation Risk (CAPTURE), the COPD in LMICs Assessment questionnaire (COLA-6), and the Lung Function Questionnaire (LFQ).

Individuals from the 3 settings were eligible for participation in the study if they were 40 years or older, able to perform spirometry, and full-time residents in the prespecified catchment areas which was defined as having lived in the area for more than 6 months.

Field workers collected socioeconomic information, medical history, and data on exposure history to cigarettes and household air pollution which included exposure to wood, dung, coal, or agricultural crop waste.

Investigators established the primary outcome as the discriminative accuracy of the 3 screening instruments for identifying COPD as measured by area under receiver operating characteristic (ROC) curves (AUCs) using previously published thresholds.

Secondary outcomes included the sensitivity, specificity, and positive and negative predictive value (PPV and NPV, respectively).

The Findings

A total of 10,709 adults were enrolled in the study, with a mean age of 56.3 years.

Of these participants, 35% had ever smoked, and 30% were currently exposed to biomass smoke.

Investigators observed that the unweighted prevalence of COPD at the 3 sites was 18.2% (642/3534 participants) in Nepal, 2.7% (97/3550) in Peru, and 7.4% (264/3580) in Uganda.

Among 1000 COPD cases, 49.3% had clinically important disease (Global Initiative for Chronic Obstructive Lung Disease classification B-D), 16.4% had severe or very severe airflow obstruction, and 95.3% of cases were previously undiagnosed.

The area under curve (AUC) for the screening instruments ranged from 0.717 (95% CI, 0.677-0.774) for LFQ in Peru to 0.791 (95% CI, 0.770-0.809) for COLA-6 in Nepal, while the sensitivity ranged from 34.8% (95% CI, 25.3%-45.2%) for COLA-6 in Nepal to 64.2% (95% CI, 60.3%-67.9%) for CAPTURE in Nepal.

The mean time to administer all of the 3 instruments was 7.6 minutes (SD 1.11), and data completeness was 99.5%.

Though COPD morbidity and screening test performance varied by site, the investigators emphasized that the data on these tools were context dependent.

“Further research is needed to assess instrument performance in other low- and middle-income settings and to determine whether implementation is associated with improved clinical outcomes,” the team wrote.

The study, "Discriminative Accuracy of Chronic Obstructive Pulmonary Disease Screening Instruments in 3 Low- and Middle-Income Country Settings," was published online in JAMA Open Network.