2% versus 31.7%; p < 0.0001) associated with the use of once-weekly alendronate compared to once-daily alendronate or risedronate over the 12 months following the initial prescription [18]. A pharmacy database

study in the US also reported that only around one-third of patients taking daily bisphosphonates and around one-half using weekly administration achieved adequate adherence. Such findings have been reiterated in other healthcare systems such as France and the UK [19, 20]. More recently, monthly administration of ibandronate has been developed with the aim of increasing adherence further [21]. However, to date, there is little published information on whether adherence to a monthly regimen is indeed superior. The PERSIST Wortmannin supplier study [22] has compared 6-month persistence rates in women randomised either to monthly ibandronate MS-275 nmr together with a patient support programme or to weekly alendronate and reported higher persistence rates in the former group (56.6% versus 38.6%; p < 0.0001). However, the relative contributions of the dosing regimen and the patient support programme in improving persistence cannot be identified in this study. On the other hand, a study in the US reported

poorer JSH-23 solubility dmso adherence in women receiving monthly ibandronate than in a historical control group treated with weekly risedronate [23]. This study is difficult to interpret since the two groups were not compared at the same time using the same protocol and because the follow-up period did not start when treatment was initiated. Given the limited amount of comparative data on adherence to monthly bisphosphonate treatment, we have undertaken a pharmacoepidemiological study whose objective was to compare adherence to weekly and monthly bisphosphonate therapy in a cohort of post-menopausal women. Materials and methods This was a retrospective pharmacoepidemiological study conducted within the context of primary healthcare in France during 2007 using medical claims data from a national

prescription database. We examined the data collected during the year preceding and the year following the introduction of ibandronate in France (January 2007). Data source We used medical claims from the Thales longitudinal prescription database. Thales is a computerised network of 1,200 general practitioners (GPs) who contribute exhaustive anonymous GNAT2 data on patient consultations and treatment to a centralised electronic database, allowing subsequent follow-up of outcomes. Analyses performed using this database have been approved by the Commission Nationale de l’Informatique et des Libertés. GPs participating in the Thales network are selected to be representative of the French GP population according to three main criteria, namely, geographical area, age and gender. Activity and prescription habits of the panel have also been compared a posteriori with national data and shown to be representative [24]. The database includes routinely collected records for >1.6 million patients.