Objectives: This study, measuring the prevalence of chronic obstructive pulmonary disease (COPD), examined (1) whether a single survey question asking explicitly about diagnosed COPD is sufficient to identify US adults with COPD and (2) how this measure compares with estimating COPD prevalence using survey questions on diagnosed emphysema and/or chronic bronchitis and all 3 survey questions together.

Methods: We used data from the 2012-2014 National Health Interview Survey to examine different measures of prevalence among 7211 US adults who reported a diagnosed respiratory condition (ie, emphysema, chronic bronchitis, and/or COPD).

Results: We estimated a significantly higher prevalence of COPD by using a measure accounting for all 3 diagnoses (6.1%; 95% CI, 5.9%-6.3%) than by using a measure of COPD diagnosis only (3.0%; 95% CI, 2.8%-3.1%) or a measure of emphysema and/or chronic bronchitis diagnoses (4.7%; 95% CI, 4.6%-4.9%). This pattern was significant among all subgroups examined except for non-Hispanic Asian adults. The percentage difference between measures of COPD was larger among certain subgroups (adults aged 18-39, Hispanic adults, and never smokers); additional analyses showed that this difference resulted from a large proportion of adults in these subgroups reporting a diagnosis of chronic bronchitis only.

Conclusions: With the use of self- or patient-reported health survey data such as the National Health Interview Survey, it is recommended that a measure asking respondents only about COPD diagnosis is not adequate for estimating the prevalence of COPD. Instead, a measure accounting for diagnoses of emphysema, chronic bronchitis, and/or COPD may be a better measure. Additional analyses should explore the reliability and validation of survey questions related to COPD, with special attention toward questions on chronic bronchitis.