One-Hour Post-Load Glucose Is Associated with Multisystem Complications in People Living with Obesity.

Background

Obesity is associated with a broad range of complications that frequently develop before the onset of type 2 diabetes mellitus (T2DM). Identifying early metabolic markers associated with such complications is essential for improving risk stratification and supporting complication-driven therapeutic strategies. Plasma glucose measured at 1 h during the oral glucose tolerance test (OGTT) has emerged as a sensitive marker of early dysglycemia and adverse cardiometabolic outcomes, but its relationship with established obesity-related complications in individuals without diabetes remains incompletely characterized. We aimed to investigate the association between 1 h post-load plasma glucose levels during OGTT and obesity-related complications in adults living with obesity without T2DM.

Methods

This observational cross-sectional study included 47 adults with obesity evaluated during their first visit to obesity clinics. Individuals with T2DM or prior use of anti-obesity pharmacotherapy were excluded. All participants underwent a standard 75-g OGTT with plasma glucose and insulin measurements at fasting, 1 h, and 2 h. Obesity-related complications were recorded retrospectively through structured questionnaires, clinical assessment, and medical record review. Between-group comparisons were performed using non-parametric tests, and repeated OGTT measurements were analyzed using non-parametric longitudinal models.

Results

Higher 1 h post-load glucose levels were observed in participants with arterial hypertension (p < 0.001), dyslipidemia (p = 0.020), metabolic dysfunction-associated steatotic liver disease (p = 0.005), impaired glucose tolerance (p = 0.027), obesity hypoventilation syndrome (p = 0.039), urinary incontinence (p = 0.038), and chronic kidney disease (p = 0.048). In most comparisons, 1 h post-load glucose demonstrated stronger discriminatory capacity than fasting or 2 h glucose values. Insulin levels increased markedly after glucose loading in all participants, reflecting generalized insulin resistance, but showed limited ability to discriminate between complication phenotypes.

Conclusions

In people living with obesity without T2DM, elevated 1 h post-load plasma glucose during OGTT is consistently associated with multisystem obesity-related complications. These findings support the clinical relevance of 1 h post-load glucose as an integrated marker of early metabolic and systemic burden that may inform complication-driven risk stratification in obesity. Due to the observational study design, causality cannot be inferred.