Any Bone Break Increases Risk for Subsequent Fracture in Older Women

Nancy A. Melville

May 11, 2021

No matter where an initial fracture occurs in a postmenopausal woman, there is a subsequent increased risk of another fracture, with the risk surprisingly highest in the youngest postmenopausal group and among certain minorities, new data indicate.

"To our knowledge, no previous prospective study has reported detailed patterns of subsequent fracture locations after initial fracture according to age strata among women in the US," the authors note in their article published online May 5 in EClinicalMedicine.

The results show that a first fracture of the lower arm or wrist, upper arm, or shoulder, upper leg, knee, lower leg, or ankle — as well as those of the hip or pelvis — were associated with an approximately three- to sixfold increased risk for subsequent fractures. The findings have important implications for clinicians, says lead author Carolyn J. Crandall, MD, professor of medicine at the David Geffen School of Medicine at the University of California, Los Angeles.

"By not paying attention to which types of fractures increase the risk of future fractures, we are missing the opportunity to identify people at increased risk of future fracture and counsel them regarding risk reduction," she said in a press statement.

Commenting on the research, Michael R. McClung, MD, stressed this message to clinicians needs to be underscored.

"This paper is one of a series of papers highlighting the fact that having a previous fracture is a risk factor for subsequent fractures," he told Medscape Medical News.

"This has been known for a very long time, but it is a point still not appreciated by patients and primary care doctors, so having another study pointing this out is important," emphasized McClung, of the Oregon Osteoporosis Center in Portland.

30% of Women's Health Initiative Participants Had a Fracture

For the study, Crandall and colleagues evaluated data on 157,282 women between the ages of 50 and 79 who were enrolled in the Women's Health Initiative between 1993 and 2018.

The women were a mean age of 63.1 years and 47,126 (30%) experienced an incident fracture during the study period.

With a mean follow-up of 15.4 years, each type of fracture was associated with an increased risk of a subsequent fracture after adjusting for age, race/ethnicity, body mass index (BMI), hormone therapy use, and other factors.

A wide range of initial risk fractures — including an initial lower arm or wrist fracture (aHR, 4.80), upper arm or shoulder fracture (aHR, 5.06), upper leg fracture (aHR, 5.11), knee fracture (aHR, 5.03), lower leg/ankle fracture (aHR, 4.10), and spinal fracture (aHR, 6.69) — increased the risk of sustaining a subsequent hip fracture. 

For initial fractures of the lower arm or wrist, there was an increased risk of a subsequent fracture of the upper arm/shoulder, upper leg, knee, lower leg/ankle, hip/pelvis, and spine (adjusted hazard ratios [aHRs] ranged from 2.63 to 5.68). 

"The finding that knee fracture has the same prognostic value for subsequent fracture as hip or wrist fracture is a novel key finding, as knee fracture is generally not considered 'osteoporotic'," the authors note.

The risk of fracture after sustaining an initial hip or pelvis fracture was exceptionally high – with as much as a 27-fold higher risk of a subsequent upper leg (nonhip) fracture (aHR, 27.18).

"Thirty-four percent of women who experienced initial hip or pelvis fracture experienced a subsequent nonhip fracture," the authors note.

However, the risks associated with an initial hip fracture are already well established, and the study's more notable findings are the risks of other bone breaks, Crandall told Medscape Medical News.

"The (increased risk with hip fracture) is a rather substantial result," she said. "However, the more major point of this study is that no matter where the initial fracture happened, the risk of the future fracture was elevated."

Don't Disregard Risks in Younger Women, Racial/Ethnic Groups

The findings regarding age are also important. The highest risk was observed in the youngest postmenopausal age group of 50-59 years (aHR, 6.45), which decreased slightly in the 60-69 age group (aHR, 6.04) and further decreased in the 70-79 age group (aHR, 4.99).

"This was a surprise, and it highlights that clinicians should not disregard initial fractures among young postmenopausal women," Crandall told Medscape Medical News.   

Even greater increased risks for a subsequent fracture following an initial lower extremity fracture were observed in non-Hispanic Black women, Hispanic or Latina women, and women of Asian Pacific Islander ethnicity, ranging from ninefold to 14-fold, versus a sevenfold risk among non-Hispanic White women.

"This has public health implications because it means that we may have been missing the opportunity to prevent fractures among younger postmenopausal women and underrepresented racial/ethnic groups," Crandall noted.

Is Risk Greatest 1-2 Years After the Initial Fracture?

The findings suggest that current treatment guidelines may need to be revisited in light of inconsistencies regarding when, and for which fracture types, to initiate treatment.

"It will be important to determine whether existing risk calculators can be adapted (or new calculators developed) to help refine decision-making to determine which of the women with fractures other than hip or vertebral fractures should be treated," the authors write.

McClung said a randomized controlled trial of osteoporosis treatment in people who present with all types of fractures would help determine whether having a knee or a wrist fracture does indeed warrant such therapy.

He further commented that future studies should evaluate the shorter- versus longer-term risks.

"The most recent research suggests that the risk of having a second fracture is much higher in the first year or two after the first or incident fracture," he observed.

"So, the next stage in research with this dataset would be to ask not what happens over a 10-year timeframe but what happens over the first year or two after the fracture."

The study was funded by the National Heart, Lung, and Blood Institute. Crandall has reported no relevant financial relationships. McClung has reported being a consultant and on the speakers bureau for Amgen and being a speaker for Alexion.

EClinicalMedicine. Published online May 5, 2021. Full text

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