Current guidelines recommend using spirometry for patients with respiratory symptoms to confirm a diagnosis of COPD. “However, only one-third of patients with a clinical diagnosis of COPD receive spirometry, which can lead to possibly incorrect diagnoses and suboptimal care,” says Arianne K. Baldomero, MD, MS. “Without spirometry, patients with COPD can be underdiagnosed or over diagnosed. Underdiagnosis can delay the initiation of appropriate treatments, whereas overdiagnosis can lead to higher healthcare utilization and unnecessary therapies.”

Evaluating Reasons Why Patients Are Missing Spirometry

Previous research has suggested that poor access to spirometry may be partly to blame for the underuse of this test, but it is unclear how factors other than access might contribute to underutilization. “Studies have shown that patients without spirometry often lack health insurance and or their local clinics do not have spirometry testing available,” says Dr. Baldomero. “However, it’s important to look more deeply into other reasons as to why patients are missing spirometry.”

For a retrospective study published in Chronic Obstructive Pulmonary Diseases, Dr. Baldomero and colleagues sought to identify factors associated with spirometry underutilization for patients who were less likely to face “widely recognized” access barriers related to travel, insurance, and availability of spirometry. “We evaluated patients who lived in urban cities and who received care in highly specialized Veterans Affairs medical centers to minimize the impact of potential problems with travel, lack of insurance, or testing barriers,”
explains Dr. Baldomero. Patients were included in the analysis only if their primary care clinic was in an academically affiliated tertiary level facility with spirometry available.

Spirometry Underutilization Persists Even in Patients With Fewer Barriers

Of the 24,300 patients included in the study, nearly 60% underwent spirometry. When compared with patients younger than 55, those aged 75 to 84 had an adjusted OR (aOR) for undergoing spirometry of 0.80, while patients aged 85 and older had an aOR of 0.47. When compared with patients who had a Charlson Comorbidity Index (CCI) score of 3 or higher, those with a CCI of 0 had an aOR for undergoing spirometry of 0.60. Patients who had not seen a pulmonary specialist had lower odds of receiving spirometry (Table).

“Underutilization of spirometry to confirm the diagnosis of COPD persists among patients who are less likely to have barriers related to travel, insurance, and availability of spirometry,” Dr. Baldomero says. “In this group of patients who did not have well-recognized barriers to spirometry testing, those who were less likely to receive spirometry included individuals who were older, had not seen a lung specialist, and had fewer underlying medical conditions. In addition to improving access to spirometry, these factors should be considered when designing programs to improve COPD care.”

Target Patients Who Are Least Likely to Receive Spirometry

Considering that spirometry continues to be underutilized in the management of COPD, expanding access alone is likely to be insufficient to address underutilization. “In patients who have a previous clinical diagnosis of COPD, it might still be worthwhile to use spirometry to confirm the diagnosis,” says Dr. Baldomero. “We should consider targeting patients who are least likely to receive spirometry, such as older patients and individuals with fewer underlying medical conditions.”

Efforts are needed to address guideline adherence. “In future studies, we’re interested in exploring the potential impact of barriers to accessing care and receipt of other guideline recommended COPD care, such as optimal inhaler therapies and tobacco cessation,” Dr. Baldomero says. “We also plan to perform qualitative interviews to explore barriers to and recommendations for receiving COPD care from the perspective of patients, clinic staff, and healthcare leaders. By understanding the barriers as the first step, we can start to think of innovative ways to address key issues to improving delivery of COPD care.”