Association of triglyceride-glucose-derived insulin resistance indices with first metatarsophalangeal joint cartilage thickness in type 2 diabetes

BACKGROUNDInsulin resistance (IR) has been linked to osteoarthritis; however, its relationship with cartilage thickness at the first metatarsophalangeal (MTP) joint in patients with type 2 diabetes (T2DM) remains unclear. AIMTo investigate the association between IR surrogates and articular cartilage thickness. METHODSWe included 98 adults with T2DM (196 first MTP joints) in this cross-sectional study.Cartilage thickness was measured by high-frequency ultrasound.IR surrogates, triglyceride-glucose (TyG) index, TyG-body mass index (TyG-BMI), TyG-waist circumference (TyG-WC), and TyG-waist-to-height ratio (TyG-WtHR), were calculated from fasting triglyceride and glucose levels, BMI, WC, and height.Generalized estimating equations (GEE) accounted for the within-subject correlation arising from bilateral joint measurements.Multivariable GEE models adjusted for sex, age, diabetes duration, joint side, hypertension, vitamin D level, peripheral neuropathy, use of statins, smoking history, and serum creatinine level were used to examine associations between IR surrogates and cartilage thickness. RESULTSIn multivariable linear GEE analyses, all four IR surrogates were significantly and inversely associated with cartilage thickness: TyG [β = -0.0337,95% confidence interval (CI): -0.0554 to -0.0120, P = 0.0023], TyG-BMI (β = -0.0007,95%CI: -0.0011 to -0.0002, P = 0.0047), TyG-WC (β = -0.0002,95%CI: -0.0003 to -0.0000, P = 0.0298), and TyG-WtHR (β = -0.0278,95%CI: -0.0516 to -0.0040, P = 0.0221).When cartilage thickness was dichotomized 4 / 27 (high-thickness group as reference), all four indices remained independently associated with increased odds of low thickness in multivariable logistic GEE analyses: TyG [odds ratio (OR) = 1.779, 95%CI: 1.069-2.961,P = 0.0266], TyG-BMI (OR = 1.011, 95%CI: 1.002-1.020,P = 0.0208), TyG-WC (OR = 1.003, 95%CI: 1.000-1.006,P = 0.0246), and TyG-WtHR (OR = 1.793, 95%CI: 1.095-2.936,P = 0.0203). CONCLUSIONHigher TyG and its derived indices (TyG-BMI, TyG-WC, and TyG-WtHR) are independently associated with lower cartilage thickness at the first MTP joint in patients with T2DM.Prospective studies are needed to assess their associations with longitudinal changes in cartilage thickness at this site.