Résumé
Introduction and Objective: People with type 1 diabetes (T1D) face increased mortality risk from poor glycemic control and psychological disorders. This study explored the bidirectional relationship between HbA1c and diabetes distress (DD), a common yet underlooked dimension of T1D care. Methods: We analyzed data from 657 adults included in the SFDT1 cohort (51% female, mean age 44±13 years) with HbA1c (%) and Problem Areas in Diabetes (PAID) scores measured twice, one year apart (T0 & T1). HbA1c was categorized as ≤7%/7.1-8%,/>8%, and DD as low (PAID<40), high (40-54), or very high (≥55) at T0. Cross-lagged panel modeling evaluated stability and bidirectional effects between T0 and T1, adjusting for age, sex, and residual correlations. Results: People with HbA1c≤7% & PAID<40 at T0 showed high HbA1c stability (autoregressive coefficient, a=0.59, p<0.05) at T1 and a negative HbA1cT0→PAIDT1 effect (cross-lagged coefficient, c=-0.15, p<0.05), suggesting good glycemic and psychological control support long-term stability and reduce DD. HbA1c>8% & PAID≥55 at T0 demonstrated high HbA1c stability (a=0.57, p<0.05) at T1 and a positive HbA1cT0→PAIDT1 effect (c=0.37, p<0.05), indicating that poor control worsens DD over time in highly distressed individuals. Sensitivity analysis in those with no treatment change (N=484) confirmed these findings. In new automated insulin delivery (AID) system initiators between T0 and T1 (N=94), PAID≥40 at T0 was linked to high glycemic level persistence (a=0.69, p<0.05) and a positive PAIDT0→HbA1cT1 effect (c=0.26, p<0.05), highlighting DD's role in hindering AID benefits. Conclusion: A bidirectional link exists between HbA1c and DD, particularly in high-distress groups. Individuals initiating AID maintain their emotional burden, even when glycemic control improves. These findings highlight the need for stratified interventions targeting jointly glycemic control and distress to improve long-term outcomes in T1D.