Triglyceride–glucose (TyG) index as a surrogate marker of insulin resistance for lung cancer risk and related outcomes: a systematic review and meta-analysis

The triglyceride–glucose (TyG) index is a surrogate marker of insulin resistance (IR). The role of this marker in lung cancer has not yet been systematically evaluated. In this study, we conducted a systematic review and meta-analysis to evaluate the role of TyG in lung cancer incidence, clinical features, and preliminary prognostic evidence. We systematically searched PubMed, Web of Science, Embase, Scopus, and the Cochrane Library on 24 May 2026 to identify studies evaluating TyG in lung cancer. We included observational studies that investigated the association between lung cancer and the TyG index, excluding preclinical studies. We used a random-effects meta-analysis to compare TyG between lung cancer and no-cancer populations, reporting standardized mean differences (SMDs) with 95% confidence intervals (CIs). Eight studies were identified, with reported study-level sample sizes totaling 717,108; because two studies used UK Biobank data, this total may include overlapping participants. Four studies had sufficient data for the meta-analysis comparing TyG levels. The meta-analysis showed significantly higher TyG levels in lung cancer patients than in controls (SMD 0.537, 95% CI 0.165 to 0.910, P = 0.0047), a similar finding in the NSCLC subgroup (SMD 0.575, 95% CI 0.056 to 1.093, P = 0.0299). Heterogeneity was extreme ( I 2 = 98.4%), and the 95% prediction interval crossed the null (− 0.80 to 1.87). The pooled result also became statistically non-significant after omitting Yan et al. (SMD 0.44, P = 0.0552). Only one study reported survival outcomes. Higher TyG levels were associated with lung cancer-related outcomes in the available studies; however, the pooled estimate was highly heterogeneous and sensitive to an individual study. TyG should therefore be considered an investigational biomarker rather than an established screening or prognostic tool.