OBJECTIVES: A regular inhaled corticosteroid (ICS) treatment is recommended to maintain symptoms, to stabilize disease progress and to reduce exacerbation risk for longer periods.  A retrospective database study was conducted to assess factors associated with ICS treatment persistence and adherence among patients with chronic obstructive pulmonary disease (COPD). METHODS: Patients ages 40 years and older with COPD (ICD-9-CM: 491.xx, 492.xx or 496.xx), and regular inhaled bronchodilator (≥3 prescriptions) and ICS (≥2 prescriptions) treatment were identified from pharmacy and medical claims data between January 1998 and December 2004. Medication persistence or treatment duration was measured as the time between initiating and discontinuing ICS therapy. Medication adherence was measured by medication possession ratio (MPR) using information about days supply and days between refills. Multivariable regression models, including season of ICS initiation, demographic characteristics, comorbidities and pre-term resource utilization patterns, were used to identify factors associated with better medication persistence and adherence. RESULTS: A total of 6873 patients were identified for analysis of persistence and adherence. Approximately 44% of patients remained on ICS treatment after 12 months. Mean (standard deviation) of MPR in the first year of treatment was 0.58 (0.30). Having commercial insurance, using specialist care, and having a spirometry test were associated with better persistence and adherence, whereas the number of chronic conditions had a negative impact. Age, census region and pre-term use of anticholinergics were also important determinants of persistence and adherence. Season of ICS treatment initiation, comorbid conditions and pre-term health care utilization had relatively minor impact. CONCLUSIONS: ICS treatment behavior can be explained not only by treatment needs but also by patient recognition about disease and treatment. Increased specialist care and improved patient education may enhance patient understanding of the importance of ICS maintenance therapy for COPD conditions.