Diabetes mellitus affects over 537 million adults worldwide, yet the impact of hyperglycemia on absorbable suture degradation remains poorly understood. This study evaluated the in vitro degradation of polyglycolic acid (PGA) and PGLA 910 copolymer sutures under glucose concentrations of 0, 300, and 600 mg/dL over 28 days. A total of 120 sutures (60 per material) were incubated at 37°C in phosphate-buffered saline with different glucose concentrations. Mechanical properties were assessed at baseline and at 7, 14, 21, and 28 days via tensile testing. Medium pH was monitored weekly, and surface morphology was characterized by scanning electron microscopy. PGLA 910 demonstrated higher baseline strength than PGA (14.56 ± 1.11 N vs. 13.37 ± 1.00 N; p < 0.001). Both materials maintained strength during the first 7 days (p = 0.080), but progressive loss occurred from day 14 onward. At day 28 in a glucose-free medium (0 mg/dL), PGA retained only 1.12 N (8.4% of initial strength), while PGLA 910 retained 3.81 N (26.2%; p < 0.001). SEM revealed more severe surface degradation in PGA than in PGLA 910. We conclude that PGLA 910 offers superior resistance to hydrolytic degradation, making it a more suitable choice for diabetic patients when extended mechanical integrity is required. However, both materials degrade extensively within 4 weeks and are unsuitable for applications requiring support beyond 3 weeks. The strong pH–strength correlation confirms the autocatalytic nature of the degradation mechanism.