Kim TY, et al. - An ASBMR task force analyzed females, treated for either ≥5 years with oral alendronate in the Fracture Intervention Trial Long-term Extension (FLEX) or ≥3 years with intravenous zoledronic acid in the Health Outcomes and Reduced Incidence with Zoledronic acid Once Yearly-Pivotal Fracture Trial Extension I (HORIZON-PFT E1), with reassessment 2-3 years later, to compare the changes in BMD and procollagen type I N propeptide, PINP, after oral or intravenous bisphosphonate use. Three years after bisphosphonate discontinuation, they assessed a greater proportion of subjects in FLEX with total hip BMD loss and greater rises in PINP exceeding the least significant change (LSC). They considered that despite a longer treatment course, alendronate might have a more rapid offset of drug effect than zoledronic acid.