Prevalence of previously undiagnosed airflow limitation in patients who underwent preoperative pulmonary function test

Although being a rapidly expanding socioeconomical burden worldwide, chronic obstructive pulmonary disease (COPD) is often overlooked because of its insidious progression. Since spirometry is the primary tool for the diagnosis of COPD, physicians should be aware of the disease in any situation where interpreting spirometry. This study was to estimate the prevalence of undiagnosed COPD among patients who underwent spirometry as a preoperative evaluation for elective surgeries. Patients aged 40 years or older who completed routine spirometry as a preoperative evaluation for elective surgeries between January to December, 2000. Medical records were reviewed for medical history, clinical findings, smoking status, and discharge diagnoses for patients who demonstrated airflow limitation (AL), defined as FEV(1)/FVC<70% on spirometry. Of the 1031 patients who qualified for the study, 263 (26%) presented AL. Sixty-nine of these patients with AL (26%) had underlying conditions that could account for AL, such as asthma and previously diagnosed COPD. The remaining 194 patients with AL (74%) were suspected to have undiagnosed COPD, 90% of which was mild in severity. Only 30 (15%) of these patients appeared to be diagnosed have received a diagnosed as COPD by physician on this occasion. This study testifies that COPD is often unnoticed, and demonstrates that every spirometry, such as in preoperative evaluation, gives a clue to identify affected individuals, for which awareness of the disease is essential.