Hip Protectors Fail the Fall Test in Nursing Homes

BOSTON, July 24 -- Hip protectors designed to lessen the impact of falls among older adults do not appear to reduce the incidence of hip fractures, researchers here found.

In a large clinical trial, nursing home residents actually had a higher rate of hip fracture when wearing foam-covered polyethylene pads than when unprotected (3.1% versus 2.5%, P=0.70), reported Douglas P. Kiel, M.D., M.P.H., of Harvard and Hebrew SeniorLife, and colleagues, in the July 25 issue of the Journal of the American Medical Association.

The results confirm "the growing body of evidence that hip protectors are not effective in nursing home populations," they wrote.

However, in an accompanying editorial Pekka Kannus, M.D., Ph.D., and Jari Parkkari, M.D., Ph.D., of the UKK Institute for Health Promotion Research in Tampere, Finland, cautioned that "these findings and those from past studies are not sufficient to make evidence-based recommendations for or against use of hip protectors among frail, nursing home residents."

These older adults in long-term care facilities have been reported to be at the highest risk of hip fractures, which are mostly associated with falls, Dr. Kiel and colleagues noted.

But, efficacy results with external hip protectors designed to absorb or redistribute the impact of a fall have been conflicting and trial design has been a problem as well, the researchers said. Furthermore, all trials had been done outside the United States.

So, the researchers conducted the Hip Impact Protection PROject (HIP PRO) to test the efficacy of a hip protector consisting of a hard polyethylene shield covered in foam and incorporated into undergarments (a product not currently commercially available).

In the study, residents at 37 nursing homes were randomized by nursing home to wear a hip protector on their left or right hip only, thus serving as their own controls.

Most participants had significant cognitive impairment and fewer than half could independently get out of bed or walk around. Only 41.5% were continent of urine most of the time; 57% had bowel continence. Few had had hip replacements (6.6%) or a history of hip fracture (15.7%).

At the 20-month planned interim analysis, the study was terminated for lack of efficacy. By that time, 1,042 nursing home residents had contributed 676 person-years of observation with a mean participation of 7.8 months.

In the intent-to-treat analysis, the incidence of hip fracture during the follow-up period showed no signal for benefit at 3.1% for protected hips compared with 2.5% for unprotected hips (P=0.70).

Adherence, monitored by three weekly unannounced visits to all participants, was 73.8% overall and over 80% for a third of the participants.

In the per protocol analysis of these 334 adherent patients, the incidence of hip fracture was similar between groups. There were 15 fractures of protected hips over 284 hip-years of observation whereas there were 10 fractures of unprotected hips over 284 hip-years of observation (5.3% versus 3.5%, P=0.42).

Likewise, more residents confirmed to have been wearing their protector at the time had a fracture to their protected hip rather than their unprotected hip (13 versus seven).

When patients were confirmed to have not been wearing the pads, hip fractures were evenly distributed between groups (six fractures to protected hips versus seven to unprotected).

The difference between groups was not significant for those who were independently mobile (3.8% protected hip versus 2.9% unprotected) or required support with walking (2.4% versus 2.1%, respectively).

Among the minority of patients (17.7%) who could answer questions about fear of falling, the mean change in this fear from baseline was a nonsignificant 0.22 on a five-point scale (P=0.78).

But, there were no adverse effects on skin or mobility reported from wearing the hip protector.

The researchers said their results confirm a Cochrane systematic review that found no evidence of hip protector efficacy overall.

"However, we cannot exclude the possibility that having only one hip protected could have modified the propensity to fall to the protected side," they noted.

"Also, we cannot exclude the possibility that residents purposely modified their gait to avoid falls or, in the midst of a fall, tried to fall on the side of the pad," they said, although they did note that the high prevalence of cognitive impairment made this an unlikely scenario.

Nevertheless, both the researchers and the editorialists concluded that further studies of hip protectors with better pad materials and better trial designs would be worthwhile.

"The importance of this health problem-falls and hip fractures among older adults-should make the work a compelling ongoing priority for health research throughout the world," Drs. Kannus and Parkkari concluded.

The study was funded by a grant from the National Institute on Aging and supported in part by the Lawrence J. and Anne Cable Rubenstein Charitable Foundation. The researchers reported no financial conflicts of interest.