OBJECTIVES: Current treatment guidelines for COPD recommend the use of bronchodilators for the management of patients with mild to moderate disease and adding inhaled corticosteroids for severe patients and patients with repeated exacerbations. This analysis evaluates COPD patients initiating treatment with either an inhaled corticosteroid or an anticholinergic to determine adherence to treatment guidelines. METHODS: In a retrospective database study, continuously enrolled patients aged 18 years and older with COPD (COPD only or COPD+asthma), who initiated therapy during year 2002 with either an inhaled corticosteroid or an anticholinergic (first fill date identified as index date) were included in the analyses. The severity of identified subjects was determined using two methods: respiratory disease-related health care utilization; and charlson comorbid score during the one-year baseline period. Presence of comorbid conditions was also determined. RESULTS: Of the 8392 patients identified as having COPD, 467 (5.56%) initiated an inhaled corticosteroid and 495 (5.90%) initiated an anticholinergic. Using respiratory related healthcare utilization in the baseline period as a proxy for disease severity, 82% of inhaled corticosteroid users were low utilizers, 14% were moderate utilizers and 4% were high utilizers whereas 53% of anticholinergic users were low utilizers, 31% were moderate utilizers and 16% were high utilizers. At baseline, mean Charlson comorbidity score was significantly lower among inhaled corticosteroid users (0.88) as compared to anticholinergic users (1.32). Also, at baseline anticholinergic users had a significantly higher percentage of patients with comorbid diagnosis of congestive heart failure, atherosclerosis, coronary heart disease, hypertension, mental illness and other lung disease. Results were also consistent in the COPD only group. All differences were significant at p<0.05. CONCLUSION: Patients initiating an inhaled corticosteroid appeared to be less severe as indicated by lower health care utilization, lower Charlson comorbid score and fewer comorbid conditions than those patients initiated on anticholinergics.