A Study of the Association between Alzheimerʹs Disease and Fractures in an Elderly Population

Purpose To examine the association between Alzheimerʹs disease and specific types of fractures in patients using a large electronic claims database. Methods The study population and controls for this cohort study were selected from a large U.S. managed care database (Ingenix LabRx Database™) ≥60 years of age with four years of continuous eligibility dating from January 1, 2001 through December 31, 2004. All patients were required to have a minimum one-year baseline assessment period. An index date was assigned to Alzheimerʹs subjects corresponding to the time of initial diagnosis (ICD-9-CM: 331.0). A total of 4,180 newly diagnosed Alzheimerʹs patients were 3:1 matched to 12,540 controls based on age, gender, and index date. Cox-proportional hazard models were used to assess the relationship while using propensity scores to control for various fracture risk factors. Results Post-index, a total of 511 (12.2%) fractures in the Alzheimerʹs cohort and 927 (7.4%) in the control group were identified. The adjusted hazard ratio (HR) relating Alzheimerʹs disease to any fracture type (ICD-9-CM: 800–829) was 1.51 (95% CI: 1.39–1.75). Specific fracture types associated with Alzheimerʹs disease were hip fractures (HR 1.80; 95% CI: 1.44–2.26), fractures of the neck/trunk (HR 1.25; 95% CI: 1.03–1.51), lower limbs (HR 1.55; 95% CI: 1.25–1.92), and upper limbs (HR 1.58; 95% CI: 1.29–1.93). No significant association was found between Alzheimerʹs disease and fractures of the skull/face (HR 1.08; 95% CI: 0.62–1.86). Other risk factors found to be associated with any fracture type included: cerebrovascular disease, glaucoma, osteoporosis/bisphosphonate use, incontinence, and antidepressant drug use. Conclusion A significant association was found between fractures of the hip, neck/trunk, lower or upper limbs and prior diagnosis of Alzheimerʹs disease.