Alzheimer's Disease is a Significant Risk Factor for Major Hip Fracture

Researchers found that AD was a significant enough risk factor for hip fracture that preventive interventions should be implemented.
Researchers found that AD was a significant enough risk factor for hip fracture that preventive interventions should be implemented.

Alzheimer's disease (AD) is a major risk factor for hip fracture, as well as mortality after hip fracture, according to a BMC Geriatrics study.1

Researchers from the University of Eastern Finland sought to determine whether the same factors predict hip fractures in patients with and without Alzheimer's disease, with the purpose of identifying ways to decrease the incidence of hip fractures. This is particularly important since the higher risk of falls and hip fractures in people with AD makes the disease a key determinant of healthcare costs. People with AD have also proven to have an increased risk of death after hip fracture compared to people who do not have AD.2

An exposure-matched cohort — the Medication and Alzheimer's disease (MEDALZ) cohort — included Finland residents who had been diagnosed with AD between 2005 and 2011 and who had no prior history of hip fracture. The cohort's age range was 34 to 105 years. The associations between sociodemographic characteristics, comorbidities, and medications and risk of hip fracture and mortality after hip fracture were assessed using Cox regression.

Incidence rates in the AD cohort were 2.19 (n of hip fractures = 4851) and 0.90 (n of hip fractures = 2336). Patients with AD had a higher relative risk of hip fracture during follow-up, and even though the risk of hip fracture increased steadily across aging in both the AD and non-AD cohorts (in both sexes), the incidence rate in the AD cohort remained consistently higher. Older age was associated with higher risk of hip fracture in both cohorts, but the association was stronger in the non-AD cohort.

Additionally, people in the AD cohort experienced hip fracture at a younger age than people in the non-AD cohort. Cardiovascular disease, stroke, diabetes, hip and knee replacements, and both behavioral and mental disorders were also more common in the AD cohort.

With regard to mortality following hip fracture, the average follow-up from hip fracture to death was 261 days (range 1 day to 7.6 years) in the AD cohort and 212 days (range 1 day to 7.6 years) in the non-AD cohort. A total of 2407 people with AD (49.6%) died after experiencing a hip fracture, while 923 people (39.5%) of people in the non-AD cohort died after experiencing a hip fracture.

While the study was limited to patients in the sample who were community-dwelling at the beginning of follow-up and data on such risk factors as smoking, bone mass density and weight changes were not available, the researchers confirmed the significance of AD as a risk factor for hip fracture and mortality after hip fracture. “The impact of AD on hip fracture risk appears to exceed the impact of other hip fracture risk factors,” according to Anna-Maija Tolppanen, PhD, lead researcher of the MEDALZ cohort. “Therefore, it would be important to develop and implement preventive measures that are suitable for persons with AD.”

References

  1. Tolppanen A-M, Taipale H, Tanskanen A, et al. Comparison of predictors of hip fracture and mortality after hip fracture in community-dwellers with and without Alzheimer's disease – exposure-matched cohort study [published online December 16, 2016]. BMC Geriatrics. 2016; doi: 10.1186/s12877-016-0383-2
  2. Baker NL, Cook MN, Arrighi HM, Bullock R. Hip fracture risk and subsequent mortality among Alzheimer's disease patients in the United Kingdom, 1988–2007. Age Ageing. 2011; 40(1):49-54.


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