The association of weight with the detection of airflow obstruction and inhaled treatment among patients with a clinical diagnosis of COPD.

BACKGROUND: Most patients with a clinical diagnosis of COPD have not had spirometry to confirm airflow obstruction (AFO). Overweight and obese patients report more dyspnea than normal weight patients, which may be falsely attributed to AFO. We sought to determine whether overweight and obese patients who received a clinical diagnosis of COPD were more likely to receive a misdiagnosis (ie, lack of AFO on spirometry) and be subsequently treated with inhaled medications.

METHODS: The cohort comprised US veterans with COPD (International Classification of Diseases, 9th Revision, code; inhaled medication use; or both) and spirometry measurements from one of three Pacific Northwest Veterans Administration Medical Centers. The measured exposures were overweight and obesity (defined by BMI categories). Outcomes were (1) AFO on spirometry and (2) escalation or deescalation of inhaled therapies from 3 months before spirometry to 9 to 12 months after spirometry. We used multivariable logistic regression with calculation of adjusted proportions for all analyses.

RESULTS: Fifty-two percent of 5,493 veterans who had received a clinical diagnosis of COPD had AFO. The adjusted proportion of patients with AFO decreased as BMI increased (P < .01 for trend). Among patients without AFO, those who were overweight and obese were less likely to remain off medications or to have therapy deescalated (adjusted proportions: normal weight, 0.69 [95% CI, 0.64-0.73]; overweight, 0.62 [95% CI, 0.58-0.65; P = .014]; obese, 0.60 [95% CI, 0.57-0.63; P = .001]).

CONCLUSIONS: Overweight and obese patients are more likely to be given a misdiagnosis of COPD and not have their inhaled medications deescalated after spirometry demonstrated no AFO. Providers may be missing potential opportunities to recognize and treat other causes of dyspnea in these patients.