OBJECTIVES: Women with PMO are most often treated with bisphosphonates (BPs), as well as with strontium ranelate (SR) and raloxifene (RLX). However, a high percentage of patients are not persistent after 1 year of therapy, which can compromise treatment effectiveness (Imaz I, Osteoporos Int 2010) and thus increase the risk of fractures. The objective was to estimate the persistence to PMO treatments in a region of Spain (Catalonia) representative of the Spanish population. METHODS: This database analysis included women with PMO from 6 primary care centers, aged ≥ 50 years who initiated BPs (alendronate, ibandronate, risedronate), SR or RLX between January 1, 2004 and June 30, 2008. Patients with cancer, other bone diseases, hospitalization>30 days or <1 year follow-up data were excluded. Persistence was measured at 1, 2 or 3 years according to prescriptions dispensed at office-based pharmacies. Three patients’ cohorts were analyzed: patients with ≥1 year (cohort 1), ≥2 years (cohort 2) and ≥3 years (cohort 3) follow-up. Patients with no access to medication for >1 month were considered non-persistent and a switch to another PMO treatment was considered a discontinuation. In a secondary analysis, switch was not considered a discontinuation. Statistics were performed using Kaplan-Meier methodology. RESULTS: A total of 3,049 patients (mean age±SD; 68.3±9.7 years) were included in cohort 1; 30% were persistent after 1 year (95%CI:27.5-32.5). In cohort 2 (n=2698; 68.9±9.3 years) persistence was 35% (CI:32.6-36.2) and 16% (CI:13.6-19.2) after 1 and 2 years respectively. In cohort 3 (n=2163; 68.4±9.5 years) persistence was 36% (CI:33.9-37.9), 20% (CI:18.3-21.7) and 9% (CI:5.9-12.1) after 1, 2 and 3 years, respectively. The results were similar by drug and frequency of administration, and also when switch was not considered a discontinuation. CONCLUSIONS: In this Spanish population of postmenopausal women with osteoporosis, persistence to treatment was poor, even when a switch was not considered a discontinuation.