In Asian countries, patients with COPD are mostly under the care of primary care physicians. Synonyms for COPD, which include chronic bronchitis and chronic emphysema, complicate the diagnostic labeling. Doctors who practice alternative/traditional medicine do not differentiate asthma from COPD, resulting in the underdiagnosis of COPD. The diagnosis is usually based on a clinical history of persistent respiratory symptoms in a cigarette smoker, as spirometric documentation of fixed airflow limitation is not routine. In tertiary care practice, a spiromet-ric determination is often included. In Japan, COPD is underdiagnosed in the population, where a large epidemiologic study found that 90% of people with COPD, based on spirometry findings, did not have a prior diagnosis of the condition, which is comparable to a corresponding 63% reported in the National Health and Nutrition Examination Study in the United States. In Japan, in a primary care setting of smokers followed up for nonrespiratory conditions, 31% were found to have COPD based on screening spirometry findings, which is within the range of 14 to 46% reported in the United States.
Pulmonary tuberculosis is a major confounder in the diagnosis of COPD as the sequelae from healed tuberculosis include restrictive, obstructive, or mixed restrictive-obstructive pulmonary dysfunction, which could modify the interpretation of the spirometric evaluation. In addition, pulmonary tuberculosis often coexists with COPD, as regions with high prevalence rates of pulmonary tuberculosis, such as Indonesia, China, and Vietnam, also experience high cigarette smoking rates.