OBJECTIVE: To evaluate utilization and asthma patient outcomes of inhaled salmeterol (long-acting beta-agonist [LABA]) alone and in combination with an inhaled corticosteroid (ICS) in a group-model managed care organization (MCO). METHODS: Using medical and pharmacy claims from a group-model MCO with approximately 175,000 covered lives, patients with a diagnosis of asthma receiving at least one inhaled salmeterol prescription during a 9-month (October 1, 2000 to June 30, 2001) period were identified. Patients were stratified into two groups, LABA and LABA/ICS, based on ICS utilization. Age, short-acting beta-agonist (SABA) use, and asthma-related emergency room (ER) visits and hospital admissions were assessed. A literature-validated medication use index was used to classify asthma severity. RESULTS: A total of 1025 asthma patients were identified (mean age 49.2 years, 61% female). Approximately 28% of patients were in the LABA group and 72% in LABA/ICS group. LABA/ICS patients were more likely to be greater than 19 years of age (87% vs. 82% in LABA group) and to receive a SABA prescription during the study period (63% vs. 43%). LABA/ICS patients had a disproportionate greater number of ER visits (22 [3%]) in comparison to LABA patients (2 [0.7%]). No hospitalizations were observed in either group. Regarding asthma severity, LABA patients had less severe forms of asthma; mild asthma (15% vs. 0% in LABA/ICS group), moderate asthma (40% vs. 13%), and severe asthma (45% vs. 87%). CONCLUSION: In comparison to inhaled salmeterol monotherapy, the addition of an ICS was a marker for more severe forms of asthma. Development of asthma quality improvement programs should consider this observation when evaluating asthma severity.