J C Lo1, C D Grimsrud2, S M Ott3, M Chandra4, R L Hui5, B Ettinger4. 1. Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA. Joan.C.Lo@kp.org. 2. Department of Orthopedic Surgery, Kaiser Permanente Oakland Medical Center, 3600 Broadway, Oakland, CA, 94611, USA. 3. Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA. 4. Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA. 5. Pharmacy Outcomes Research Group, Kaiser Permanente California, 1800 Harrison Street, Oakland, CA, 94612, USA.
Abstract
In a northern California population of older women who were treated with oral bisphosphonate drugs, the incidence of atypical femur fracture, a rare complication of treatment, increased with longer duration of bisphosphonate exposure. These findings align with those previously reported in an independent southern California population. INTRODUCTION: The age-adjusted incidence of atypical femur fracture (AFF) reported in southern California increased with bisphosphonate (BP) exposure, ranging up to 113 per 100,000 person-years for 8-10-year exposure. This study examines the incidence of AFF in a northern California population. METHODS: Women age 45-89 years who initiated oral BP during 2002-2014 in Kaiser Permanente Northern California were followed for AFF outcome, defined by a primarily transverse diaphyseal femur fracture through both cortices, with focal periosteal/endosteal hypertrophy, minimal trauma, and minimal/no comminution. Total BP exposure was determined from dispensed prescriptions. The incidence of AFF, calculated for 2-year BP categories ranging from < 2 to > 10 years, was age-adjusted using the 2000 US Census. RESULTS: Among 94,542 women, 107 experienced an AFF during or < 1 year after BP cessation (mean exposure 6.6 ± 3.0 years and total days' supply 5.7 ± 2.8 years at AFF). A strong relationship between AFF incidence and increasing BP exposure was seen, more than doubling for each 2-year category until 8-10 years. Among women with 2- to < 4-year BP, the crude and age-adjusted incidence was 18 and 9 per 100,000 person-years but increased over 2- and 5-fold for women with 4- to < 6- and 6- to < 8-year BP, respectively. For those receiving ≥ 8-year BP, the crude and age-adjusted incidence peaked at 196 and 112 per 100,000 person-years exposure. CONCLUSION: Incidence of AFF increases markedly after 4-6 years of BP. These trends align with southern California and confirm a strong BP duration-related risk of this rare but serious event.
In a northern California population of older women who were treated with oral bisphosphonate drugs, the incidence of atypical femur fracture, a rare complication of treatment, increased with longer duration of bisphosphonate exposure. These findings align with those previously reported in an independent southern California population. INTRODUCTION: The age-adjusted incidence of atypical femur fracture (AFF) reported in southern California increased with bisphosphonate (BP) exposure, ranging up to 113 per 100,000 person-years for 8-10-year exposure. This study examines the incidence of AFF in a northern California population. METHODS: Women age 45-89 years who initiated oral BP during 2002-2014 in Kaiser Permanente Northern California were followed for AFF outcome, defined by a primarily transverse diaphyseal femur fracture through both cortices, with focal periosteal/endosteal hypertrophy, minimal trauma, and minimal/no comminution. Total BP exposure was determined from dispensed prescriptions. The incidence of AFF, calculated for 2-year BP categories ranging from < 2 to > 10 years, was age-adjusted using the 2000 US Census. RESULTS: Among 94,542 women, 107 experienced an AFF during or < 1 year after BP cessation (mean exposure 6.6 ± 3.0 years and total days' supply 5.7 ± 2.8 years at AFF). A strong relationship between AFF incidence and increasing BP exposure was seen, more than doubling for each 2-year category until 8-10 years. Among women with 2- to < 4-year BP, the crude and age-adjusted incidence was 18 and 9 per 100,000 person-years but increased over 2- and 5-fold for women with 4- to < 6- and 6- to < 8-year BP, respectively. For those receiving ≥ 8-year BP, the crude and age-adjusted incidence peaked at 196 and 112 per 100,000 person-years exposure. CONCLUSION: Incidence of AFF increases markedly after 4-6 years of BP. These trends align with southern California and confirm a strong BP duration-related risk of this rare but serious event.
Authors: Joan C Lo; Romain S Neugebauer; Bruce Ettinger; Malini Chandra; Rita L Hui; Susan M Ott; Christopher D Grimsrud; Monika A Izano Journal: BMC Musculoskelet Disord Date: 2020-12-03 Impact factor: 2.362
Authors: Wei Zhou; Jeroen G J van Rooij; Peter R Ebeling; Annemieke J M H Verkerk; M Carola Zillikens Journal: Curr Osteoporos Rep Date: 2021-02-15 Impact factor: 5.096
Authors: Nitesh D Dhanekula; Gareth Crouch; Karen Byth; Sue Lynn Lau; Albert Kim; Edward Graham; Andrew Ellis; Roderick J Clifton-Bligh; Christian M Girgis Journal: JBMR Plus Date: 2022-02-17
Authors: Wei Zhou; Hanh H Nguyen; Denise M van de Laarschot; Tet Sen Howe; Joyce S B Koh; Frances Milat; Jeroen G J van Rooij; Joost A M Verlouw; Bram C J van der Eerden; Mark Stevenson; Rajesh V Thakker; M Carola Zillikens; Peter R Ebeling Journal: JBMR Plus Date: 2022-07-03