OBJECTIVE: Obstructive lung disease is a leading cause of morbidity and mortality worldwide. Some patients are readmitted, but currently predicting parameters for identifying these patients are lacking. The aim of this study was to quantify the incdence of readmission in chronic obstructive lung disease and to identify determinants for hospital readmission. METHODS: We conducted a cohort study using the PHARMO record linkage system, including demographic details and complete medication histories of more than two million community-dwelling residents in the Netherlands from 1985 onwards. Eligible patients were adult users of inhaled corticosteroids (ICS) with an admission for obstructive lung disease. The outcome parameter was readmission within afollow-up period of one year. RESULTS: We identified 605 ICS users with an admission for chronic obstructive lung disease, 132 of these patients were readmitted. Readmission was associated with a high Chronic Disease Score (adjusted HR 2.4; 95% CI 1.1-5.3). Patients using short courses of systemic corticosteroids only (adjusted HR 0.5; 95% CI 0.4-0.8) or combined with antibiotics (adjusted HR 0.4; 95% CI 0.2-0.6) were at decreased risk of readmission. The effect of high-dose ICS use varied over time. CONCLUSIONS: Treatment of exacerbations out of the hospital was associated with a decreased risk of readmission, while patients with multiple chronic diseases are at increased risk of readmission for obstructive lung disease. These patients should be educated and should be invited to consultation more often to be able to detect exacerbation in an early phase and start treatment as early as possible.