OBJECTIVES: Several studies have shown that secondary fracture prevention programs such as Fracture Liaison Services (FLSs) are cost-effective. It is important to determine how visits attendance affects the health economic impact of FLSs with follow-ups. This study aims to assess the cost-utility of a FLS with a systematic follow-up according to visit compliance trajectories based on real-life data. METHODS: Clinical and administrative data from the Lucky Bone^TM FLS, a prospective cohort study conducted in Quebec (Canada), was used. Fragility fracture patients (>40 years) were investigated, treated and followed over two years. Group-based trajectory modelling (GBTM) was used to identify follow-up visits’ compliance trajectory groups. Markov decision analytics models were built using rates of investigation, treatment, persistence, and costs of the intervention. Published literature was used to complement data. A healthcare system perspective with a lifetime horizon was modelled (2-year cycles). Incremental cost-utility ratios (ICURs) were measured to compare costs (expressed as 2018 Canadian dollars) and quality adjusted life years (QALYs) between trajectories of follow-up and usual care. Costs and effects were discounted at 1.5%. RESULTS: The Lucky Bone^TM FLS enrolled 532 fragility fracture patients (85.7% women, mean age 63 years). Three trajectory groups were identified using the GBTM: high followers, intermediate followers, low followers; the probabilities of group-membership were 48.4%, 28.1% and 23.5%, respectively. The ICURs calculated for high, intermediate and low followers versus usual care were $29,118, $52,942 and $124,618 per QALY gained, respectively. When trajectories were combined to compare the FLS to usual care, the ICUR was $38,804 per QALY gained. CONCLUSIONS: The results of this study suggest that a FLS with a systematic follow-up is cost-effective when considering a $50,000 threshold. They also highlight the importance of better understanding what predicts patient retention into FLS program since patients are at risk of subsequent fragility fractures.