Severity of COPD at initial spirometry-confirmed diagnosis: data from medical charts and administrative claims

Douglas W Mapel¹, Anand A Dalal², Christopher M Blanchette^3,4, Hans Petersen³, Gary T Ferguson^5
1Lovelace Clinic Foundation, Albuquerque, NM, USA; ²US Health Outcomes, GlaxoSmithKline, Research Triangle Park, NC, USA; ³Lovelace Respiratory Research Institute, Kannapolis, NC, USA; ⁴University of North Carolina Eshelmen School of Pharmacy, Chapel Hill, NC, USA; ⁵Pulmonary Research Institute of Southeast Michigan, Livonia, MI, USA

Purpose: This study was conducted to determine COPD severity at the time of diagnosis as confirmed by spirometry in patients treated in a US managed care setting.
Patients and methods: All patients with one or more inpatient stays, one or more emergency department visits, or two or more outpatient visits with diagnosis codes for COPD during 1994–2006 were identified from the Lovelace Patient Database. From this group, a subset of continuously enrolled patients with evidence in claims of a first available pulmonary function test or pulmonary clinic visit and a confirmatory claim for a COPD diagnosis was selected. Medical chart abstraction was undertaken for this subset to gather information for diagnosis and severity staging of each patient based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD.
Results: Of the 12,491 patients with a primary or secondary COPD diagnosis between 1994 and 2006, there were 1520 continuously enrolled patients who comprised the study cohort. Among the 648 eligible records from patients with evidence of a pulmonary function test, 366 were identified by spirometry as having COPD of GOLD stage I or higher (average percentage of predicted forced expiratory volume in 1 second: 60%): 19% were diagnosed at the stage of mild disease (GOLD stage I); 50% at moderate disease (GOLD stage II); and 31% at severe or very severe disease (GOLD stage III or IV, respectively). The majority of patients in these groups were not receiving maintenance treatment.
Conclusion: The results demonstrate a very low incidence of early-stage diagnosis, confirmed by a pulmonary function test, of COPD in a large US sample and support calls for increased screening for COPD and treatment upon diagnosis.

Keywords: lung function, Global Initiative for Chronic Obstructive Lung Disease (GOLD), detection, early treatment