Persistent empiric COPD diagnosis and treatment after pulmonary function test showed no obstruction

BACKGROUND: Health-care providers often diagnose and empirically treat COPD without a confirmative pulmonary function test (PFT) or even despite a PFT that is not diagnostic of obstructive lung disease. We hypothesized that a portion of patients continue to carry a persistent empiric COPD diagnosis and receive treatment with bronchodilators and inhaled steroids after a PFT shows no obstruction. METHODS: We retrospectively reviewed single PFT sessions with both spirometry and plethysmography in 1,805 subjects. We included subjects who had a normal PFT or a restrictive ventilatory defect. Persistent empiric COPD diagnosis and treatment were defined when subjects with normal PFTs or a restrictive ventilatory defect continued to carry a health-care provider COPD diagnosis or receive treatment with bronchodilators and/or inhaled glucocorticoids, respectively, after a PFT showed no obstruction. RESULTS: One quarter of subjects with FEV₁/FVC ≥ lower limit of the normal range had nonspecific PFT abnormalities. We included 473 subjects with normal PFTs and 382 with a restrictive ventilatory defect (n = 855). Persistent empiric COPD diagnosis (60 of 855, 7% prevalence) was associated with current (odds ratio [OR] = 44.7, P < .001) and former smoking (OR = 17.3, P < .001) and older age (OR = 1.03/y, P = .005). Persistent empiric treatment (208 of 855, 24%) was associated with empiric COPD diagnosis (OR = 24.6, P < .001), female sex (OR = 1.75, P = .002), current (OR = 2.04, P = 0.040) and former smoking (OR = 1.53, P = 0.029), interstitial lung disease (OR = 2.09, P = .001), other respiratory diagnosis (OR = 3.17, P < .001), and obstructive sleep apnea (OR = 1.79, P = .006). CONCLUSIONS: Persistent empiric COPD diagnosis was 7%, but persistent empiric treatment was common.