Risk of fall-related injury requiring medical care is higher in elderly patients, women and non-white races with lower limb amputations than in other populations, according to data published recently in the Journal of Rehabilitation Medicine.
According to the study, fall-related injuries account for 20% of nearly $20 billion in annual cost of accidental injury in the United States, yet there is little data assessing risk in community-dwelling lower limb amputees.
Christopher Kevin Wong, PT, PhD, OCS, associate professor of Rehabilitation and Regenerative Medicine at Columbia University Medical Center, conducted a study to explore these risks and identify a predictive model for fall-related injury.
Patients and parameters
Following a prospective longitudinal cohort design, the study included 41 community-dwelling adults with bilateral or unilateral lower limb amputations of any etiology or surgical level.
Most of the patients were men and mean age was 56.9 years. Mean time since amputation was 6.7 years.
The subjects attended an initial outpatient assessment session to complete a demographic and medical information questionnaire, self-report prosthetic use for mobility and balance confidence scales and complete a performance-based balance assessment.
Medical information included age, sex, race, weight, height, medical comorbidities, amputation etiology and level, years since amputation, prosthesis use and number of falls in the past 12 months.
More than half of the patients reported a history of at least one fall within the previous 12 months in both the injured and uninjured groups. During the study, of the 11 patients who had a fall-related injury, 10 had amputations of vascular etiology.
Follow-up data were obtained by telephone or in person at support group meetings or prosthetic clinic visits every 6 months for periods of up to 4 years.
“We looked at all sorts of different variables,” Wong told O&P News. “But I think what makes this study unique is that we followed patients for such a long period of time.”
Primary outcome measures included self-reported falls and fall-related injury. Fall frequency was categorized as no fall, a single fall or repeated falls. Fall-related injury severity was defined as requiring no medical care, a visit to the emergency room or physician, hospitalization or surgery.
Prosthetic use for mobility was assessed with the Houghton scale, which quantifies daily prosthesis wear, use of the prosthesis, walking aids and perceived stability walking on various terrains. The subjective perception of balance confidence was assessed with the self-reported Activities-specific Balance Confidence scale, assessing confidence when performing 16 common activities of daily living. Balance ability was assessed by testers trained to administer the Berg Balance Scale.
Study results showed 56.1% of patients reported at least a single fall and 26.8% experienced a fall-related injury requiring medical care. Results also showed that 73.2% of patients received no care because they did not experience a fall or the fall resulted in only minor injuries.
The incidence of fall-related injury was 14.1 per 1,000 person-months and greater fall frequency correlated with greater injury severity.
“I think it is interesting [because this] number is much greater than the rate of falls in other types of people known to be at fall risk,” Wong said. “Older people for instance, living in institutions, are at risk to fall but that number is smaller than the risk for amputees.
“In other words, people with amputations, even though they are living in the community and therefore probably healthier than people living in an institution, are still at a greater risk for fall-related injury.”
Older age in lower limb amputees correlates with increased hospitalization due to fall-related injury and also associated with greater incidence of vascular disease, which could lead to poor health, decreased activity and reduced risk due to the decreased opportunity to fall.
Women were nearly six-times more likely than men to experience fall-related injury. Injury rate among women was 5.88-times that among males throughout the study period. Women in general are also particularly vulnerable to fractures of the lumbar spine, pelvis and hip following a fall.
“This is one of the surprises,” Wong said. “Usually, men are at greater risk than women because the theory goes: men are more risk-taking. So the fact that women were [at higher risk] was interesting.”
In addition, findings showed after adjusting for vascular etiology, patients of non-white race were 13-times more likely to experience fall-related injury than those of white race.
Amputation etiology was not a significant independent predictor for fall-related injury when adjusting for age, sex and race.
There were some limitations to the study, Wong said. The small sample size limited the number of variables considered for the final model, producing results that show correlation, not causation.
No attempts were made to specify precipitating circumstances of the fall, the specific injury experienced or the outcome of any recovery. The clinic or support group from which the patients were recruited was not recorded, current medications were not documented and the time of injury was approximate due to the self-reported data.
Additionally, while minor injuries such as scrapes and bruises that did not require medical care, were unlikely to incur substantial health care costs, they could have an impact on overall prosthetic function.
No other prospective longitudinal study of fall-related injury in people with amputations could be identified for comparison.
The study findings warrant future research and prevention strategies, such as wellness or physical therapy programs, prosthetic components and safety education, Wong said. Further study into the economic status of people with lower limb amputation and costs of fall-related injury are also warranted.
“We should be working as clinicians, doing more to figure out how we can prevent falls and fall-related injuries,” Wong said. “We are not sure how to do that yet, but that is where current research is going.”
Wong recently published another study in which a clinical prediction rule assesses which amputees would be successful independent community ambulators after one year. He said it could be useful to spot patients who are not headed for ambulation and get them greater access to care before a fall occurs. – by Shawn M. Carter
- Wong CK. J Rehabil Med. 2016;doi:10.2340/16501977-2042.
Disclosure: Wong reports the research was supported in part by grant 1 R49 CE002096 from the National Center for Injury Prevention and Control of the CDC to the Center for Injury Epidemiology and Prevention at Columbia University.