Unipedal stance test alone is as effective as combination of unipedal stance and timed up and go test for prediction of femoral fracture

Background: Unipedal stance test (UPS) and timed up and go test (TUG) are test to evaluate physical function of elderly. In Korea, we have national screening program, in which UPS and TUG are performed simultaneously to evaluate physical function of elderly. This study aimed to elucidate the effectiveness of UPS to predict femoral fracture is not inferior to combination of UPS and TUG. Method: We used data from National Screening Program for the Transitional Ages in Korea (2007 – 2011), in which UPS and TUG were performed simultaneously to participants of 66 years. We used Cox regression of UPS alone and combination of UPS and TUG to calculate hazard ratio for femoral fracture, adjusted for sex, depression, dementia, Parkinson's disease and comorbidities. And we calculated Harrell's C-index. Results: Total 1,423,509 participants were included. They were all 66 years old. 5.3% (75,713/1,423,509) was experienced fall before screening. About twelve percent (102,175/1,423,509) had abnormal UPS results, and 1.5% (12,211/1,423,509) had abnormal TUG results. Adjusted hazard ratio (aHR) for femoral fracture of UPS alone was 1.15 (95% CI 1.11 – 1.19), and Harrell's C-index was 0.640 (95% CI 0.636 – 0.644). And aHR of combination of UPS and TUG was 1.16 (1.12 – 1.21), and Harrell's C-index was 0.641 (0.637-0.644). Conclusion: UPS alone was not inferior to combination of UPS and TUG for prediction of femoral fracture. Because UPS is a convenient to perform in primary care, UPS alone could replace combination of UPS and TUG, current mass screening tool in Korea.