SAT-524 Re-hospitalization And Mortality Outcome Following Atypical Femur Fracture

INTRODUCTION: Older women with proximal femur (hip) fractures have high morbidity and mortality; over 10% are re-hospitalized within 30 days of discharge and the overall mortality at 1 year is 20-25%. Outcomes differ for women with atypical femur fractures (AFF), although published findings have shown conflicting results. One study found a greater risk of death in patients with AFF (median survival 9 months) compared to non-AFF diaphyseal femur fractures, although AFF cases also had greater comorbidity burden (JCD 19:359-67, 2016). A second study found that mortality was much lower for patients with AFF compared to non-AFF diaphyseal fractures, with no deaths in the first year following fracture (JBMR 31:491-497, 2015). This study further examines morbidity and mortality in women who experienced an AFF, focusing on rehospitalization and all-cause mortality outcome in comparison to proximal femur fractures. METHODS: This retrospective cohort study used post-fracture outcome data from 112 women (age 67.1 ± 8.4, 63% Asian, 26% white, 11% all others) who experienced an AFF after initiating oral bisphosphonate therapy in 2002-2014. Exclusion criteria included use of intravenous bisphosphonates, teriparatide, denosumab, skeletal disorders, or advanced chronic kidney disease. Women were followed up to 1 year after the initial AFF event to determine rehospitalization outcome within 30 and 90 days of discharge. Mortality was examined at 6 months and 1 year after AFF, and results were compared to published findings for typical femur fractures occurring in the same healthcare setting. RESULTS: Among 112 women who had an AFF during 2002-2015, 38% were age 65-74 years and 22% age 75-84 years; none were age 85 and older. This contrasts with previous findings in older women with hip fracture where more than one-third were age 85 and older, the age subgroup with highest mortality (over 30%). Six women with AFF were re-hospitalized within 30 days (5.4%) and 10 within 90 days (8.9%), with principal indications for rehospitalization within 30 days relating to infection (3/6) and cardiac arrhythmia (2/6). Six-month and one-year mortality were extremely low at 0.9% overall, and by age group: 2% among age <65 years, 0% among women age 65-74 years and 0% among women age 75-84 years. These results contrast with much higher one-year mortality previously reported for women age 65-74 years (14%) and 75-84 years (18%) who experienced a proximal femur fracture within the same health plan setting. DISCUSSION: Women with AFF appear to have substantially different survival outcomes compared to women with typical femur (hip) fracture, consistent with findings reported in other studies. Whether these differences are primarily related to health status and physical function, or the relationship of chronic disease and (typical) fracture risk, should be further examined.