Hip Fracture in Postmenopausal Women After Cessation of HT
Objective: Millions of women in the United States and across the globe abruptly discontinued postmenopausal hormone therapy (HT) after the initial Women's Health Initiative trial publication. Few data describing the effects of HT cessation on hip fracture incidence in the general population are available. We evaluated the impact of HT cessation on hip fracture incidence in a large cohort from the Southern California Kaiser Permanente health management organization.
Methods: In this longitudinal observational study, 80,955 postmenopausal women using HT as of July 2002 were followed up through December 2008. Data on HT use after July 2002, antiosteoporotic medication use, and occurrence of hip fracture were collected from the electronic medical record system. Bone mineral density (BMD) was assessed in 54,209 women once during the study period using the dual-energy x-ray absorptiometry scan.
Results: After 6.5 years of follow-up, age- and race-adjusted Cox proportional hazard models showed that women who discontinued HT were at 55% greater risk of hip fracture compared with those who continued using HT (hazard ratio, 1.55; 95% CI, 1.36-1.77). Hip fracture risk increased as early as 2 years after cessation of HT (hazard ratio, 1.52; 95% CI, 1.26-1.84), and the risk incrementally increased with longer duration of cessation (P for trend < 0.0001). Longer duration of HT cessation was linearly correlated with lower BMD (β estimate [SE]) = -0.13 [0.003] T-score SD unit per year of HT cessation; P < 0.0001).
Conclusions: Women who discontinued postmenopausal HT had significantly increased risk of hip fracture and lower BMD compared with women who continued taking HT. The protective association of HT with hip fracture disappeared within 2 years of cessation of HT. These results have public health implications with regard to morbidity and mortality from hip fracture.
Since the publication of the initial Women's Health Initiative (WHI) trial findings in June 2002, millions of women have discontinued postmenopausal hormone therapy (HT), and HT prescriptions have concordantly dropped. In a survey of US obstetrician-gynecologists, although 53% of clinicians reported that they were unlikely to change their HT prescription pattern after WHI, 93% of their patients were willing to discontinue HT, and 92% were less likely to request HT. It is clearly apparent that a large number of postmenopausal women abruptly stopped HT after the initial WHI publications. However, little epidemiologic research of the clinical outcomes associated with HT cessation has been evaluated in these women.
Protection from bone loss and fracture is a conclusive HT benefit. It is therefore conceivable that hip fracture risk, which is associated with a 25% case-fatality rate, has increased in the post-WHI era. However, this potential public health malady has not been examined in the general population. In a large cohort of 80,955 postmenopausal women who were using HT until June 2002, we calculated the hip fracture incidence after HT cessation compared with those who continued using HT.
Abstract
Objective: Millions of women in the United States and across the globe abruptly discontinued postmenopausal hormone therapy (HT) after the initial Women's Health Initiative trial publication. Few data describing the effects of HT cessation on hip fracture incidence in the general population are available. We evaluated the impact of HT cessation on hip fracture incidence in a large cohort from the Southern California Kaiser Permanente health management organization.
Methods: In this longitudinal observational study, 80,955 postmenopausal women using HT as of July 2002 were followed up through December 2008. Data on HT use after July 2002, antiosteoporotic medication use, and occurrence of hip fracture were collected from the electronic medical record system. Bone mineral density (BMD) was assessed in 54,209 women once during the study period using the dual-energy x-ray absorptiometry scan.
Results: After 6.5 years of follow-up, age- and race-adjusted Cox proportional hazard models showed that women who discontinued HT were at 55% greater risk of hip fracture compared with those who continued using HT (hazard ratio, 1.55; 95% CI, 1.36-1.77). Hip fracture risk increased as early as 2 years after cessation of HT (hazard ratio, 1.52; 95% CI, 1.26-1.84), and the risk incrementally increased with longer duration of cessation (P for trend < 0.0001). Longer duration of HT cessation was linearly correlated with lower BMD (β estimate [SE]) = -0.13 [0.003] T-score SD unit per year of HT cessation; P < 0.0001).
Conclusions: Women who discontinued postmenopausal HT had significantly increased risk of hip fracture and lower BMD compared with women who continued taking HT. The protective association of HT with hip fracture disappeared within 2 years of cessation of HT. These results have public health implications with regard to morbidity and mortality from hip fracture.
Introduction
Since the publication of the initial Women's Health Initiative (WHI) trial findings in June 2002, millions of women have discontinued postmenopausal hormone therapy (HT), and HT prescriptions have concordantly dropped. In a survey of US obstetrician-gynecologists, although 53% of clinicians reported that they were unlikely to change their HT prescription pattern after WHI, 93% of their patients were willing to discontinue HT, and 92% were less likely to request HT. It is clearly apparent that a large number of postmenopausal women abruptly stopped HT after the initial WHI publications. However, little epidemiologic research of the clinical outcomes associated with HT cessation has been evaluated in these women.
Protection from bone loss and fracture is a conclusive HT benefit. It is therefore conceivable that hip fracture risk, which is associated with a 25% case-fatality rate, has increased in the post-WHI era. However, this potential public health malady has not been examined in the general population. In a large cohort of 80,955 postmenopausal women who were using HT until June 2002, we calculated the hip fracture incidence after HT cessation compared with those who continued using HT.
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