Do Nationally Representative Cutpoints for Clinical Muscle Weakness Predict Mortality? Results from 9 Years of Follow-up in the Health and Retirement Study

Abstract

Background: Muscle weakness, as measured by handgrip strength, is associated with cardiovascular and all-cause mortality; however, there are wide inconsistencies in the magnitude of these effects due to divergent definitions used to define muscle weakness across studies. Therefore, the objective of this study was to examine the relationship between previously defined sex-and race-specific cutpoints of clinical muscle weakness and early mortality. Methods: Data come from the 2006-2014 Health and Retirement Study. Time-varying clinical muscle weakness, as defined by handgrip strength cutpoints, was the primary exposure. Time to death, ascertained from the National Death Index, was the outcome of interest. The association between time-varying clinical muscle weakness and early mortality across a 9-year observation period was determined using Kaplan-Meier methods and extended Cox regression. Results: Out of the 8,326 individuals in the study, 1,799 deaths (21%) occurred during the observation period. Median follow-up time was 8.3 years (SD ±1.9 years). Weak individuals had a steeper decline in their survival trajectory, compared to non-weak individuals (Log-Rank test, p