OBJECTIVES: To evaluate persistence of weekly drug treatment with alendronate and risedronate over 12 months in primary care patients using the DIN-LINK observational database. METHODS: The DIN-LINK longitudinal patient database sourced from medical records in UK was used to identify and follow-up a cohort of patients with prescriptions for once weekly administration of alendronate or risedronate. Follow-up period was 12 month. The proportion of patients remaining on drug treatment was calculated with the Kaplan-Meier product-limit method. The log-rank test was used to evaluate the statistical significance of observed differences between treatment groups. Results were considered to be statistically significant if the corresponding p value was below 0.05. Analyses were performed using SPSS for windows release 11.5.1. RESULTS: In the database 2132 patients on weekly administration of alendronate and 356 patients on weekly administration of risedronate were identified. After 12 month 60.6% (95% CI 58% - 63%) of patients are remaining on alendronate and 69.7% (CI 65% - 74%)of patients are remaining on risedronate. The persistence with alendronate is different to risedronate (p = 0.0015). The compliance rate expressed as medication possession ratio (MPR) was 75.5% and 83.3% for alendronate and risedronate, respectively. CONCLUSIONS: Results demonstrate a higher compliance and persistence with weekly bisphosphonate than reported previously from analyses in US claims databases. In fact, the study reveals that patients taking once-a-week risedronate show a high compliance rate (MPR > 80%). It has previously been demonstrated that improving compliance in actual practice may significantly decrease osteoporosis related fracture risk. We conclude, that an once-a-week dosing regimen with risedronate provides favourable compliance and persistence to effectively prevent fractures.