Guidelines recommend the confirmation of a COPD diagnosis with spirometry. ICD-9-CM diagnostic codes are used frequently to identify patients with COPD for administrative purposes. However, coding the diagnosis of COPD does not require spirometric confirmation. The purpose of this study was to determine how often the discharge diagnoses of COPD is supported by spirometric measurements in the VA health system.
We reviewed records of patients hospitalized for COPD in a VA teaching hospital between 2005 and 2015. Individuals were counted once; rehospitalizations for COPD in the same time frame were excluded. Patients’ records were assessed for presence of spirometric measurements and for spirometric evidence of COPD.
There were 1278 discharges with the principal diagnosis of COPD and allied conditions in the time frame. A total of 826 discharged-patients were included. Among them, 21% had no spirometric measurements, 12% were unable to perform the breathing maneuvers correctly, 56% had spirometric evidence of airways obstruction and 11% had normal pre or post bronchodilator FEV1/FVC measurements. Older patients were more likely to fail the spirometry or have no documented spirometry. Younger patients were more likely to have the first spirometry after their COPD hospitalizations.
Caution must be taken when using the discharge diagnosis database to measure health care outcomes and determine resource management. Efforts are needed to assure that patients clinically suspected to have COPD are tested with spirometry to improve the accuracy of diagnosis of COPD.