Response to: time to mobilization in hours after surgery for hip fracture and 30-day mortality-a study on 36 229 patients from the Danish hip fracture registry

Dear Editor, We read with great interest the nationwide cohort study by Kristensen et al., Time to mobilization in hours after surgery for hip fracture and 30-day mortality, which analyzed over 36 000 patients from the Danish Hip Fracture Registry.1 Hip fracture remains one of the most common and serious orthopedic emergencies in older adults. While surgery is the only definitive treatment, postoperative mobilization is central to recovery. Current guidelines, including those from the UK National Institute for Health and Care Excellence (NICE), recommend mobilization on the day after surgery unless contraindicated.2 However, guidelines do not tend to differentiate between mobilization within 12, 24, or 36 hours. As one of the first studies to examine mobilization at such granular intervals within a large national cohort, this represents a robust and important contribution. And we commend the authors. The results are compelling: even modest delays in mobilization were associated with increased mortality. A clear pattern was evident across 12-hour bands, with the lowest mortality among patients mobilized within 12 hours. Compared with mobilization within 24 hours, mobilization at 24-36 hours was associated with an adjusted hazard ratio of 1.22 (95% CI 1.07-1.38). The use of stabilized inverse probability of treatment weighting strengthens confidence in the findings by attempting to address baseline imbalances. These findings align with emerging evidence linking early mobilization to reduced infection risk3,4 and lower long-term opioid use.5