Diagnostic Accuracy of the Short Physical Performance Battery for Detecting Frailty in Older People

Background: The Short Physical Performance Battery (SPPB) is widely used to predict negative health-related outcomes in older adults. However, the cutoff point for the detection of the frailty syndrome is not yet conclusive. Objective: The aim of this study was to determine the diagnostic value of the SPPB for detecting frailty in community-dwelling older adults. Design: This was a population-based cross-sectional study focusing on households in urban areas. A total of 744 people who were 65 years old or older participated in this study. Methods: Frailty was determined by the presence of 3 or more of the following components: unintentional weight loss, self-reported fatigue, weakness, low level of physical activity, and slowness. Diagnostic accuracy measures of the SPPB cutoff points were calculated for the identification of frailty (individuals who were frail) and the frailty process (individuals who were considered to be prefrail and frail). Receiver operating characteristic curves were constructed. Odds ratios for frailty and the frailty process and respective CIs were calculated on the basis of the best cutoff points. A bootstrap analysis was conducted to confirm the internal validity of the findings. Results: The best cutoff point for the determination of frailty was <= 8 points (sensitivity = 79.7%; specificity = 73.8%; Youden J statistic = 0.53; positive likelihood ratio = 3.05; area under the curve = 0.85). The best cutoff point for the determination of the frailty process was <= 10 points (sensitivity = 75.5%; specificity = 52.8%; Youden J statistic = 0.28; positive likelihood ratio = 1.59; area under the curve = 0.76). The adjusted odds of being frail and being in the frailty process were 7.44 (95% CI = 3.90-14.19) and 2.33 (95% CI = 1.65-3.30), respectively. Limitations: External validation using separate data was not performed, and the cross-sectional design does not allow SPPB predictive capacity to be established. Conclusions: The SPPB might be used as a screening tool to detect frailty syndrome in community-dwelling older adults, but the cutoff points should be tested in another sample as a further validation step.