In moderate-severe chronic obstructive pulmonary disease (COPD), long-acting bronchodilators (LBs) are recommended to improve the quality of life. The aims of this study were to measure adherence to LBs after discharge for COPD, identify determinants of adherence, and compare amounts of variation attributable to hospitals of discharge and primary care providers, i.e. local health districts (LHDs) and general practitioners (GPs). This cohort study was based on the Lazio region population, Italy. Patients discharged in 2007-2011 for COPD were followed up for 2 years. Adherence was defined as a medication possession ratio >80%. Cross-classified models were performed to analyse variation. Variances were expressed as median odds ratios (MORs). An MOR of 1.00 stands for no variation, a large MOR indicates considerable variation. We enrolled 13,178 patients. About 29% of patients were adherent to LBs. Adherence was higher for patients discharged from pneumology wards and for patients with GPs working in group practice. A relevant variation between LHDs (MOR = 1.21, p = 0.001) and GPs (MOR = 1.28, p = 0.035) was detected. When introducing the hospital of discharge in the model, the MOR related to LHDs decreased to 1.05 (p = 0.345), MOR related to GPs dropped to 1.22 (p = 0.086), whereas MOR associated with hospitals of discharge was 1.38 (p < 0.001). Treatments with proven benefit for COPD were underused. Moreover, a relevant geographic variation was observed. This heterogeneity raises equity concerns in access to optimal care. The reduction of variability among LHDs and GPs after entering the hospital level proved that differences we observe in primary care partially 'reflect' the clinical approach of hospitals of discharge.
Keywords: Adherence to long-acting bronchodilators; COPD; cross-classified multilevel models; discharge from hospital after an acute exacerbation; geographic variation; primary care providers.