Validity and Utility of a Modified Short Physical Performance Battery Assessment and Scoring Approach in Middle-Aged and Older Adults

Abstract

OBJECTIVES: Despite the widespread usage of the Short Physical Performance Battery (SPPB), psychometric limitations in the SPPB have impeded its use for outcome monitoring and clinical decision making. We propose an alternative assessment and scoring approach for the SPPB, and we compared the modified and the original SPPB on their discriminative and clinical value concerning the risk of prefrailty/frailty, probable sarcopenia, and restricted life-space mobility (RLSM).

DESIGN: Cross-sectional study conducted from June 2018 to August 2023.

SETTING AND PARTICIPANTS: A community-dwelling sample of 2331 participants [mean (SD), 66 (7.5) years; 71% women] completed a survey and fitness assessment.

METHODS: SPPB scores, FRAIL (fatigue, resistance, ambulation, illness, and loss of weight) scores, handgrip strength, and Life-Space Assessment scores were obtained from all participants. SPPB modifications involved (1) increasing the difficulty of the full-tandem balance test and (2) adopting a continuous scoring system. Participants with a FRAIL score ≥1, a weak handgrip strength (<18 kg for women and <28 kg for men), and a Life-Space Assessment <60 points were classified as having prefrailty/frailty, probable sarcopenia, and RLSM, respectively. Discriminative validity was evaluated using multivariable logistic regression and area-under-the-curve (AUC) analyses, whereas clinical utility was assessed using decision curve analysis.

RESULTS: The proposed modifications significantly reduced the ceiling effect of the SPPB (original vs modified SPPB: 70% vs 27%, P < .001) and improved its discriminative validity for prefrailty/frailty, sarcopenia, and RLSM outcomes (AUC increments, 0.03-0.08; P values < .001). In decision curve analyses, these improvements translated to greater net benefit particularly in the 10% to 20% decision risk range.

CONCLUSIONS AND IMPLICATIONS: Although requiring further validation in diverse populations and longitudinal studies, the proposed modifications to the SPPB have the potential to widen its scope of use and facilitate more accurate risk stratification and granular outcome monitoring in community-dwelling adults.