Comparative Effectiveness of Functional Tests in Fall Prediction After Hip Fracture

Abstract

Objectives: To assess the validity of 4 functional tests in predicting falls within the first year after hip fracture.

Design: Prospective study of functional tests shortly after hip surgery and incident falls during 12 months' follow-up.

Setting and participants: The sample comprised 173 adults with acute hip fracture, aged 65 years and older (79% women, 77% community dwelling, mean age 84.2 years), who participated in a clinical trial of vitamin D or home exercise.

Methods: We assessed 4 functional tests [Timed Up and Go test (TUG), grip strength, and knee flexor and extensor strength in the nonoperated leg] by trained study physiotherapists at baseline (1-12 days after hip fracture surgery). During 12 months' follow-up, we ascertained all fall events by monthly personal phone calls, a telephone hotline, and a patient diary. Then we compared TUG and strength test performance at baseline between future single fallers, recurrent fallers, and nonfallers over the 12-month follow-up. All analyses adjusted for age, body mass index, gender, 25-hydroxyvitamin D status at baseline, days of follow-up, and treatment allocation (the original trial tested vitamin D treatment and/or a home exercise program).

Results: Ninety-two of 173 (53%) participants fell and experienced 212 falls. Participants who became recurrent fallers (n = 54) had significantly longer TUG times at baseline than those who did not fall (n = 81) in the following 12 months (mean TUG for recurrent fallers = 71.6 seconds, SD = 8.2 seconds, vs mean TUG for nonfallers = 51.4 seconds, SD = 6.9 seconds; P = .02). There were no significant differences in TUG times between single fallers and nonfallers. For all 3 strength tests, there were no significant differences between single fallers, recurrent fallers, and nonfallers.

Conclusions and implications: In this population of frail older adults recruited shortly after hip fracture surgery, only the TUG test discriminated between future recurrent fallers and nonfallers over a 12-month follow-up. Because of the high incidence and serious consequences of falls in older adults after a hip fracture, it is very important to identify practical and clinically related tests to predict repeated falls in the first year after a hip fracture, which is of great public health importance.

Keywords: Falls; Timed Up and Go test; functional assessments; grip strength; hip fracture; knee flexor and extensor strength.