Osteoporosis in the Oldest Old - From Diagnosis to Treatment: A Narrative Review

BACKGROUND: Osteoporosis and fragility fractures are major causes of disability, loss of independence, institutionalization, and mortality in the oldest old. Despite their exceptionally high fracture risk, adults aged ≥80 years remain underrepresented in randomized controlled trials. Diagnosis and treatment are complicated by the interaction of skeletal fragility with falls, sarcopenia, frailty, multimorbidity, cognitive and functional impairment, and competing mortality. SUMMARY: This narrative review discusses the diagnosis, fracture-risk assessment, non-pharmacological management, and pharmacological treatment of osteoporosis in the oldest old. Bone mineral density (BMD) remains central to osteoporosis diagnosis but incompletely characterizes fracture risk at advanced age. Previous and particularly recent fractures, prevalent vertebral fractures, falls, physical performance, nutritional status, and frailty provide complementary information. Interpretation of the Fracture Risk Assessment Tool FRAX® requires particular consideration in the oldest old because competing mortality may cause 10-year fracture probabilities to plateau or decline despite increasing age-specific fracture incidence; FRAXplus® incorporates additional risk modifiers, including falls and the number and recency of previous fractures. Non-pharmacological interventions addressing nutrition, muscle function, balance, and falls complement bone-directed pharmacotherapy. Available evidence does not indicate that chronological age itself attenuates the efficacy of osteoporosis pharmacotherapy, although direct randomized fracture-endpoint evidence in adults aged ≥80 years remains limited. Risedronate and, historically, strontium ranelate provide some of the clearest fracture data specifically in this age group, whereas evidence for most other therapies derives from older-subgroup analyses, skeletal efficacy studies, observational data, or extrapolation from pivotal trials. At advanced age, renal function, cognition, mobility, adherence, caregiver support, and continuity of care increasingly influence the translation of efficacy into clinical effectiveness. KEY MESSAGES: Fracture risk in the oldest old reflects the interaction of skeletal fragility with falls, frailty, sarcopenia, and functional reserve. Available evidence supports preservation of pharmacological antifracture efficacy with advancing age, but direct evidence in octogenarians and particularly nonagenarians remains scarce. Treatment feasibility and continuity of care become increasingly relevant at advanced age. Greater representation of the oldest old in clinical trials is needed, with particular attention to fracture outcomes, treatment sequencing, time to benefit, and outcomes relevant to independence and quality of life.