Role of Gait Speed, Strength, and Balance in Predicting Adverse Outcomes of Acutely Ill Older Outpatients

Aim To evaluate the ability of the Short Physical Performance Battery (SPPB) for predicting 1-year adverse outcomes of acutely ill older outpatients. Methods Prospective study with 512 acutely ill older outpatients (79.4 +/- 8.3 years, 63% female) in an acute care day hospital. The SPPB was administered at admission. Participants were classified as low (0-4 points), intermediate (5-8 points), or high (9-12 points) performance. Primary outcomes were new dependence in basic activities of daily living (ADL), hospitalization, and death at 1 year. Cox models tested whether the SPPB predicted outcomes after adjustment for sociodemographic factors, comorbidities and well-known geriatric conditions. We also estimated whether the chair-stand and balance tests improve the SPPB's ability to identify patients at high risk of adverse outcomes. Results Patients with intermediate or low SPPB performance were at higher risk of 1-year new ADL dependence (32% vs 13%: adjusted hazard ratio [aHR]=2.00; 95%CI=1.18-3.37; 58% vs 13%: aHR=3.40; 95%CI=2.00-5.85, respectively), hospitalization (43% vs 29%: aHR=1.56; 95%CI=1.04-2.33; 44% vs 29%: aHR=1.80; 95%CI=1.15-2.82), and death (18% vs 6%: aHR=2.54; 95%CI=1.17-5.53; 21% vs 6%: aHR=2.70; 95%CI=1.17-6.21). Use of all three components (versus gait speed alone) improved predictions of new ADL dependence (Harrell's C=0.73 vs 0.70;P=0.01), hospitalization (Harrell's C=0.60 vs 0.57;P=0.04), and death (Harrell's C=0.67 vs 0.62;P=0.04). Conclusions The SPPB is as a powerful tool for identifying acutely ill older outpatients at high-risk of adverse outcomes. The combination of the three components of the SPPB resulted in better predictive performance than gait speed alone.