Impact of TCF7L2 rs7903146 on clinical presentation and risk of complications in patients with type 2 diabetes

Aims: TCF7L2 rs7903146 is the most impactful single genetic risk variant for type 2 diabetes. However, its role on disease progression, complications and mortality among people with type 2 diabetes at diagnosis remains unclear. Materials and Methods: We assessed the per allele impact of the rs7903146 T-allele on clinical characteristics and complication risk in 9231 individuals with type 2 diabetes at diagnosis and over a 10-year follow-up period. Log-binomial and robust Poisson regression analyses were used to estimate prevalence ratios for clinical characteristics and macro- and microvascular complications at diabetes onset, while Cox regression was applied to estimate the risk of complications post-diagnosis. Analyses were adjusted for sex, calendar year at birth, age at enrollment and diabetes duration. Results: The per T-allele impact was associated with 0.6 kg/m² (95% CI: 0.4, 0.8) lower BMI, 1.4 cm (95% CI: 1.0, 1.8) smaller waist circumference, 5.6% (95% CI: 4.2, 7.0) lower insulin secretion and 5.0% (95% CI: 3.3, 6.7) higher insulin sensitivity. Over 10 years, the per T-allele impact was associated with lower risks for major adverse cardiovascular events (0.87 [95% CI 0.79, 0.95]), myocardial infarction (0.82 [95% CI: 0.72, 0.93]) and heart failure (0.85 [95% CI 0.73, 1.00]), with no significant impact on microvascular complications. Conclusions: The TCF7L2 variant is associated with less obesity, lower insulin secretion and higher insulin action at diabetes onset, and decreased risk of cardiovascular events following type 2 diabetes onset.