Handgrip strength as a complementary test for mobility limitations assessment in acutely hospitalized oldest old

INTRODUCTION Clinically viable screening tools for detecting individuals at heightened risk for mobility limitations is warranted. However, it remains unclear in acutely hospitalized patients (> 75 years) whether handgrip strength might be a good predictor for "proxy" muscle strength. OBJECTIVE To examine the reliability and validity of handgrip strength test in acute hospitalized older adults in comparison with other standardized muscular strength tests, and (ii) to examine its ability to discriminate between presence and absence of mobility limitations. DESIGN Cross-sectional study. SETTINGS AND PARTICIPANTS A total of 223 patients (mean 86.5 years old, 46% women) admitted to a tertiary public hospital between 2016 and 2017 were recruited. METHODS Maximal (1RM) and power muscle output of the upper and lower extremity along with functional capacity (as assessed with Barthel index and the Short Physical Performance Battery [SPPB]), and cognitive function was measured at admission. Functional impairment (mobility limitations) was defined at SPPB≤7 points. Pearson's correlation and multivariable linear regression were evaluated between handgrip test and maximal and muscle power output as the reference method to assess concurrent validity. Receiver operating characteristic analysis was used to estimate handgrip strength cutoff point for likelihood of mobility limitations to assess predictive validity. RESULTS Findings show moderate-to-strong correlations between standardized muscular strength (reference methods) and handgrip strength test (r= 0.501 to 0.779). All muscular strength tests show moderate accuracy (area under curve >0.7). Handgrip strength shows the higher positive predictive value (87%), and therefore a lower number of false positives. The overall handgrip strength cutoff point for likelihood of mobility limitations was 18.4 kg for men and women. CONCLUSIONS AND IMPLICATIONS Handgrip strength may be a useful tool for detecting acutely hospitalized older who are at risk of mobility limitations and could aid in focusing interventions on those with higher risk.