BACKGROUND: Currently, osteoarthritis (OA) is recognized as a systemic disease, wherein metabolic disturbances play a part in joint degeneration and elevated risk of mortality. This study investigates the prognostic value of the triglyceride-glucose (TyG) index in determining all-cause and cerebral cardiovascular mortality among OA patients, accentuating the necessity for customized interventions. METHODS: A cohort of osteoarthritis patients from the 1999-2018 NHANES was linked to the 2019 National Death Index (NDI) for mortality confirmation. TyG index correlation with all-cause and cerebral cardiovascular mortality was assessed using Cox regression and Kaplan-Meier curves. Non-linear associations were examined with restricted cubic splines, and a two-piecewise Cox model was built around the inflection point. RESULTS: A total of 4145 OA patients were followed for a median of 89 months, during which 1109 all-cause deaths and 427 cerebral cardiovascular-related deaths were observed. Restricted cubic splines showed an inverse L-shaped relationship between the TyG index and both types of mortality. The critical point was identified as 9.48, with a 1-unit increase associated with a 71% and 91% rise in adjusted all-cause and cerebral cardiovascular mortality, respectively (HR 1.71
95% CI 1.30, 2.26 and HR 1.91
95% CI 1.28, 2.86). Subgroup analyses revealed significant associations between the TyG index and elevated mortality risks among non-white OA patients and those with concurrent diabetes. CONCLUSION: In OA patients, the TyG index and mortality (both all-cause and cerebral cardiovascular) share an inverse L-shaped relationship, with identified thresholds at 9.48. This threshold offers valuable insight for risk assessment, thus promoting a shift towards personalized healthcare strategies founded on metabolic status for enhanced outcomes within OA populations. Key points • The TyG index predicts all-cause and cerebral cardiovascular mortality in OA patients. • An inverse L-shaped relationship between the TyG index and mortality was found, with a critical threshold of 9.48. • Non-white OA patients and those with diabetes show significant associations with elevated mortality risks, highlighting the importance of personalized care.