Operationalizing Short Physical Performance Battery (SPPB) with muscle strength and power: predicting adverse events in older adults from the ilsirente study

Background and aims: The present study examined associations between Short Physical Performance Battery (SPPB) indexes operationalized according to lower limb muscle strength and power and the incidence of adverse events in older community-dwellers. Methods: This was a prospective cohort study of octogenarians who lived in the mountain community of the Sirente geographic area in Central Italy. Participants completed the SPPB under standardized conditions. Lower limb muscle power was estimated according to results from the 5-time sit-to-stand (5STS) test using validated equations. Then, four SPPB indexes were created by replacing 5STS test results with muscle power measures. Outcomes were assessed 24 months after baseline and included falls, fractures, and death. Results: Data of 255 older adults (mean age: 85.8 ± 4.8 years; women: 67.0%) were examined. Binary regression analysis indicated that conventional SPPB was significantly associated with the incidence of falls (Odds ratio [OR] = 0.841, [95% confidence interval [CI]] = 0.758, 0.934), fractures (OR = 0.837, 95%CI = 0.702, 0.998), and death (hazard ratio = 0.961, 95%CI = 0.934, 0.999). However, no significant results were found when SPPB was operationalized according to muscle power parameters. Area under the curve (AUC) results indicated that SPPB indexes had lower accuracy for distinguishing participants at higher risk of negative events. Discussion and conclusions: Results of the present study indicate that conventional SPPB, but not SPPB indexes operationalized according to lower limb muscle power, was significantly associated with the incidence of negative events in older adults. However, SPPB indexes were not good to identify older adults at higher risk of experiencing negative events.