Abstract
Background Although altered grip strength is a recognized predictor of various central nervous system disorders, large-scale clinical evidence linking it to delirium and postoperative delirium (POD) remains scarce. Using data from the UK Biobank (UKB), this study investigated the association between baseline grip strength and the future risk of incident delirium. Methods We analyzed 452,711 UKB participants without delirium at baseline. Grip strength was measured at study entry. Incident delirium was identified from hospital records using ICD-10 code F05. POD was defined by the occurrence of surgery before delirium diagnosis, using postoperative windows of 3 and 7 days. Accelerated failure time (AFT) were used in the primary analyses to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). The proportional hazards assumption was assessed using Schoenfeld residual tests. Because sex modified the associations of interest, sex-stratified analyses were performed. Restricted cubic spline analyses and Kaplan-Meier curves were used to characterize dose-response patterns and cumulative incidence. Results Over a median follow-up of 14.9 years, 7695 incident delirium events were identified. Lower baseline grip strength was associated with higher risks of incident delirium and POD. Sex modified these associations, particularly for incident delirium and POD defined within 3 days after surgery. In both males and females, restricted cubic spline analyses supported inverse associations between grip strength and the risks of incident delirium, POD within 3 days, and POD within 7 days. Kaplan-Meier curves showed higher cumulative incidence across decreasing grip strength tertiles. In fully adjusted models, lower grip strength remained associated with higher risks across outcomes in both sexes. The lowest grip strength tertile consistently showed the highest risk. In females, however, the intermediate tertile was associated with incident delirium but not with POD. Conclusion Lower baseline grip strength was independently associated with higher risks of incident delirium and POD, with modest sex-related differences in the strength of association. Grip strength measurement may offer a simple, noninvasive means of identifying individuals at increased risk of delirium-related outcomes.