Short physical performance battery como preditora de mortalidade em idosos da comunidade

Abstract

The Short Physical Performance Battery (SPPB) is an instrument for assessing physical performance widely used in research among the elderly in multiple settings both at national and international levels. The scientific literature has mentioned an association of the SPPB with adverse health outcomes, however, the accuracy of this instrument for the outcome mortality is not well established and there is a scarcity of studies in Brazil. This study aimed to analyze if the SPPB scale has predictive ability for mortality among community-dwelling older adults. This was an observational study, with longitudinal design (2017-2020), which used data from previous research (baseline 2017, n= 411), conducted with community-dwelling older adults living in urban area on the district of Macapá-AP. Socioeconomic, clinical and health variables, physical performance and mortality were collected. The predictive ability of SPPB was established by multivariate Cox regression analysis, with death as the outcome. In addition, survival analysis was performed using the Kaplan-Meier method, considering a 95% confidence interval (CI) and 5% significance level (p<0.05), through the Statistical Package for Social Sciences (SPSS), version 25.0. To determine the cut-off points to discriminate mortality, Receiver Operating Characteristic (ROC) curves were constructed, with the parameters of area over the ROC curve (AUC), by means of the MedCalc program, version 11.4.4. During the follow-up of the study (2017-2020), 34 (8.3%) deaths and 336 (81.8%) survivors were found among the elderly in the sample. Kaplan-Meier survival curves indicated that seniors with worse levels of performance on the SPPB scale and the balance and gait speed tests had a lower probability of survival compared to seniors with better levels. The adjusted multivariate Cox regression model pointed to SPPB score as a predictor for mortality (hazard ratio, HR= 0.72; 95%CI: 0.59-0.88. Elderly with very poor and low physical performances on SPPB had higher risks for mortality (HR= 9.67; 95%CI: 1.20-77.65; HR= 4.06; 95%CI: 1.09-15.01), respectively. As for the subtests, those with low performances in the balance test (HR= 0.54; 95%CI: 0.36-0.81) and walking speed (HR= 0.50; 95%CI: 0.33-0.76) had higher risks for the outcome death, and the same was reproduced for low scores in the categories in each of the tests, balance (2 points, HR= 5.86; 95%CI: 1.84-18.61) and walking speed (2 points, HR= 5.07; 95%CI: 1.76-14.58). The area under the ROC curve analysis for men was 0.655 (95%CI: 0.57-0.74; p= 0.044) and for women was 0.667 (95%CI: 0.60-0.73; p= 0.029). A cut point ≤ 9 on the SPPB scale was a discriminating criterion for mortality in elderly subjects of both genders. Therefore, elderly with worse physical performance on the SPPB scale had shorter survival and higher risk of death compared to those with better performance. The total SPPB score, as well as the balance and gait speed tests were predictors of mortality in the sample studied. Moreover, the SPPB is accurate in predicting mortality among community-dwelling elderly.