The fracture risk after ischemic stroke (FRAC-Stroke) score is a useful diagnostic tool to identify individuals surviving ischemic stroke who are at risk for suffering low-trauma fracture within first year of stroke diagnosis. This type of information can be used to select those individuals that will benefit from densitometry screening or therapy with bisphosphonates, according to the results of a study published in JAMA Neurology.
The study took place between July 2003 and March 2012, and the consisted of 20,435 individuals. The primary outcome was the occurrence of new low-trauma fractures within the first year of discharge. Individuals studied included those hospitalized with ischemic stroke and later discharged alive from any of the 11 regional stroke centers listed in the Ontario Stroke registry. Those with hemorrhagic or inpatient stroke or ≤18 years were excluded. Controls consisted of a sample of 13,698 individuals admitted for stroke within 5 years.
Mean age of the individuals studied was 71.6±14 years, of which 9564 (46.8%) were women. A total of 741 individuals (3.6%) had low-trauma fracture within 1 year of their stroke. Older individuals (80-89 and 90-99 years) had a higher risk for fracture (adjusted hazard ratio [aHR] 2.23; 95% CI, 1.14-4.37 and adjusted hazard ratio [aHR] 1.69; 95% CI, 1.43-2.00, respectively). Other factors associated with low-trauma fracture were discharge modified Rankin score (mRS), rheumatoid arthritis, osteoporosis, falls, and previous fractures. Amongst controls, the predicted and observed rate of low-trauma fractures were comparable. Discharge mRS was an important discriminator of risk. The highest risk was seen in individuals with mRS 3 and 4, and the lowest was seen in bedbound individuals (mRS 5).
From lowest to highest FRAC-Stroke quintile, the cumulative incidence of 1-year low-trauma fracture increased from 1.3% in the lowest quintile to 9.0% in the highest quintile. The FRAC-Stroke score predicted low fractures risk with good discrimination (C statistic 0.70).
Limitations of this study included lack of accuracy regarding the diagnosis of low-trauma fractures as information was obtained from administrative health data. Also, information such as family history of hip fracture, smoking, alcohol use, weight, glucocorticoid use, or bone mineral density could not be obtained.
Study investigators concluded that the FRAC-Stroke risk score could aid clinicians in identifying high risk individuals at risk for low-trauma fracture within 1 year of stroke, and further aid in intervention planning. Individuals with stroke and 1-year risk >0.8% should be considered for bone densitometry screening. For high-risk individuals (1-year risk, ≥2.0%), the use of bisphosphonates could be considered regardless of bone mineral density.
Multiple authors declared associations with the pharmaceutical industry. Please see original reference for a full list of authors’ disclosures.
Smith EE, Fang J, Alibhai SM, et al. Derivation and external validation of a scoring system for predicting fracture risk after ischemic stroke in a Canadian cohort [published online May 13, 2019]. JAMA Neurol. doi:10.1001/jamaneurol.2019.1114