A clinical study of COPD severity assessment by primary care physicians and their patients compared with spirometry

Primary care physicians often do not use spirometry to confirm the diagnosis of chronic obstructive pulmonary disease. This project was designed to see how well physicians' impressions about their patients' chronic obstructive pulmonary disease severity correlate with the severity of airflow obstruction measured by spirometry and to assess whether spirometry results subsequently changed the physicians' opinions about chronic obstructive pulmonary disease severity and treatment.

We performed a multicenter, cross-sectional, observational study conducted in 83 primary care clinics from across the United States. A total of 899 patients with a clinical diagnosis of chronic obstructive pulmonary disease completed a questionnaire and spirometry testing. Physicians completed a questionnaire and case report forms. Concordance among physician ratings, patient ratings, and spirometry results was evaluated.

Physicians' chronic obstructive pulmonary disease severity ratings before spirometry were accurate for only 30% of patients with evaluable spirometry results, and disease severity in 41% of patients was underestimated. Physicians also underestimated severity compared with patients' self-assessment among 42% of those with evaluable results. After spirometry, physicians changed their opinions on the severity for 30% of patients and recommended treatment changes for 37%. Only 75% of patients performed at least 1 high-quality spirometry test; however, the physicians' opinions and treatment decisions were similar regardless of suboptimal test results.

Without performing spirometry, physicians are likely to underestimate their patients' chronic obstructive pulmonary disease severity or inadequately characterize their patients' lung disease. Spirometry changed the physicians' clinical impressions and treatments for approximately one third of these patients; thus, spirometry is a valuable tool for chronic obstructive pulmonary disease management in primary care.