Sex-specific handgrip strength thresholds for short-term mortality risk stratification in Mexican older adults: derivation in MHAS and validation in Mex-Cog.

PURPOSE: Handgrip strength (HGS) is widely used in geriatric assessment, but mortality-oriented thresholds may not be directly transportable across populations. We aimed to derive sex-specific HGS thresholds for short-term mortality in Mexican adults aged ≥50 years and evaluate their performance in a primary non-overlapping validation sample. METHODS: We conducted a secondary analysis of the Mexican Health and Aging Study and its ancillary Mex-Cog study. Sex-specific thresholds were derived in MHAS 2012 participants with HGS data and mortality follow-up through 2015 using receiver operating characteristic analysis and Youden's index. The derived thresholds were then applied without modification to a non-overlapping Mex-Cog 2016 validation sample, with mortality assessed through 2018 as a fixed-horizon binary outcome. Logistic regression models estimated associations with mortality. RESULTS: The derivation cohort included 1922 participants, of whom 95 (4.9%) died. HGS showed acceptable discrimination overall (AUC 0.7219, 95% CI 0.6688-0.7751), in men (AUC 0.7806, 95% CI 0.7101-0.8510), and in women (AUC 0.7347, 95% CI 0.6668-0.8026). The derived thresholds were ≤ 28 kg in men and ≤ 18 kg in women. In the primary non-overlapping validation sample (n = 966; 55 deaths), HGS at or below the threshold was associated with higher mortality after age- and sex-adjustment (OR 2.33, 95% CI 1.15-4.73) and in the expanded complete-case model (OR 2.13, 95% CI 1.02-4.43). CONCLUSION: Sex-specific HGS thresholds identified Mexican adults at higher short-term mortality risk and retained prognostic utility in a non-overlapping validation sample within the same study platform. These thresholds should be interpreted as practical markers of vulnerability rather than stand-alone predictors of individual mortality.