Insulin Resistance Metabolic Score as a predictor of gestational diabetes mellitus: evidence from NHANES 1999-2016

Introduction: Background: gestational diabetes mellitus (GDM) is a prevalent condition during pregnancy, driven by β-cell dysfunction in an insulin-resistant state. Metabolic Score for Insulin Resistance (METS-IR), a surrogate marker that does not require insulin measurement, has demonstrated predictive value in several metabolic conditions. Its applicability in GDM populations, however, remains unclear. Objective: to explore the association between the METS-IR and GDM based on a cross-sectional study. Methods: data from NHANES (1999-2016) were utilized, covering 472 pregnant women. The link between METS-IR and GDM risk was examined via weighted logistic regression. Potential nonlinearity of this relationship was further investigated using RCS models. Subgroup analyses were conducted to examine variations in this association across different demographic groups. Results: after controlling for potential confounders, a positive correlation was identified between METS-IR and GDM risk (OR = 1.07, 95 % CI: 1.02-1.12). When METS-IR was divided into tertiles, the highest tertile (METS-IR > 41.95) demonstrated a 5.43-fold higher risk of GDM relative to the lowest tertile (METS-IR ≤ 34.61) (95 % CI: 1.87-15.75). Subgroup analyses suggested that this association was more evident in individuals over 25, with a high school education or less, low income, and non-drinkers (OR > 1, p < 0.05). Further interaction tests showed significant interactions between education level and the ratio of family income to poverty in the relationship between METS-IR and GDM (p < 0.05). Conclusion: METS-IR, a practical and cost-efficient metabolic index, shows promise as an early indicator of GDM risk.