Background: COPD is a significant cause of morbidity and mortality. Guidelines recommend the confirmation of a COPD diagnosis with spirometry. Limited evidence exists, however, documenting the frequency of spirometry use in clinical practice.
Methods: The National Committee for Quality Assurance recruited five health plans to determine the proportion of patients ≥ 40 years old with a new diagnosis of COPD who had received spirometry during the interval starting 720 days prior to diagnosis and ending 180 days after diagnosis. Patients were identified via International Classification of Diseases, Ninth Revision diagnostic codes for encounters during the period July 1, 2002, through June 30, 2003. For each patient, the participating plans provided patient demographic and claims data from administrative data systems.
Results: Participating health plans covered 1,597,749 members with a total of 5,039 eligible COPD patients identified. Patients in the 40 to 64 age range had the highest percentage of new COPD diagnoses. Women were also slightly more likely to undergo spirometry (33.5% vs 29.4%, p = 0.001). Approximately 32% of patients with a new diagnosis of COPD had undergone spirometry in the specified interval. Spirometry frequency was lowest in older patients, with the lowest frequency in those ≥ 75 years old.
Conclusions: Our study suggests that approximately 32% of a broad range of patients with a new COPD diagnosis had undergone spirometry within the previous 2 years to 6 months following diagnosis. In addition, spirometric testing appeared to decrease with increasing age. As opposed to a prior report, women were not less likely to have undergone spirometry. This study shows that spirometry is infrequently used in clinical practice for diagnosis of COPD and suggests opportunities for practice improvement.