Source: Collins BF, et al. Chest 2014;
146:1513-1520.

Some commonplace disorders can readily misdirect clinicians about the presence of other important diagnoses. For instance, in patients with chronic obstructive pulmonary disease (COPD), deterioration of cardiac function, leading to congestive heart failure, can easily be misinterpreted as worsening COPD since fatigue, exercise, intolerance, and dyspnea are common to both. Could obesity misdirect clinicians in their diagnostic process for COPD? This report from the Veterans Administration system suggests that it can.

Collins et al reviewed data of obese veterans diagnosed with COPD who had undergone spirometry. Approximately half of COPD patients did not demonstrate airflow obstruction (necessary for the diagnosis of COPD) upon spirometry. After spirometry was performed, obese persons were less likely than normal weight individuals to have inhaler medications decreased or discontinued. The data found that as the degree of obesity increased in these COPD patients, the likelihood that airflow obstruction would be found on spirometry decreased.

Although clinicians may be tempted to diagnose COPD based simply on symptoms alone, these data indicate that obese patients are particularly likely to be misdiagnosed with COPD, incurring potentially inappropriate medications and distracting clinicians from attaining a correct diagnosis to explain patients’ symptoms. Clinicians would be wise to follow clinical guidelines that indicate spirometry as the gold standard for COPD diagnosis.