Short Physical Performance Battery as a Crosswalk Between Frailty Phenotype and Deficit Accumulation Frailty Index

Background: Growing evidence supports the clinical importance of evaluating frailty in older adults, with its strong outcome relevance. We aimed to assess whether the Short Physical Performance Battery (SPPB) correlates with frailty status according to phenotype and deficit accumulation models and can be used as a link between these models.

Methods: We analyzed records of 1064 individuals from the Aging Study of Pyeongchang Rural Area, a population-based, prospective cohort from South Korea. Frailty was determined using the Cardiovascular Health Study (CHS) phenotype (phenotype model), 26- and 34-item frailty indices (deficit accumulation model). Associations of SPPB score and frailty with a composite outcome of mortality or long-term institutionalization were assessed. Crosswalks for SPPB, the CHS frailty phenotype, and the frailty index were created.

Results: The mean age of the study population was 76.0 years, and 583 (54.8%) were women. According to the CHS phenotype, 26- and 34-item frailty indices, 242 (22.7%), 161 (15.1%), and 280 (26.3%) participants, respectively, had frailty. Sensitivities/specificities for classifying CHS phenotype, 26- and 34-item frailty indices were 0.93/0.55, 0.71/0.84, and 0.80/0.83 by SPPB cut points of ≤9, ≤6, and ≤7, respectively. C-index of SPPB score (0.78) showed a predictive ability for the composite outcome that was comparable to that of CHS frailty phenotype (0.79), 26- (0.78), and 34-item frailty indices (0.79).

Conclusions: We could create a crosswalk linking frailty phenotype and frailty index from correlations between SPPB and frailty models. This result may facilitate clinical adoption of the frailty concept in a broader spectrum of older adults.