Prognosis for Type 1 Diabetes with Diabetic Nephropathy between 2000 and 2020- Changes in Kidney Function Decline Over Time and Development of Cardiovascular Disease, Kidney Failure, and Mortality

Introduction: Individuals with type 1 diabetes (T1D) and diabetic nephropathy (DN) experience progressive kidney function decline and high risk of cardiovascular disease (CVD) and mortality. This study explored changes in kidney function decline in new-onset DN between 2000 and 2020 and provided an updated prognosis for risk of kidney failure, CVD, and mortality. Methods: This is a register-based cohort study in T1D with new-onset DN (severely increased albuminuria) between 2000 and 2020 at Steno Diabetes Center Copenhagen, Denmark. Data were derived from electronic health records and national registers. Kidney function development was expressed as trajectories of estimated glomerular filtration rate (eGFR) and measured GFR (mGFR) using mixed-effects models. The prognosis was presented in probabilities of developing complications, stratified by sex, prior CVD, and risk factor control by using simulations based on Poisson regression analysis. Results: The cohort comprised 591 individuals with median (interquartile range [IQR]) age at DN onset of 53 (39-66) years and 57% were male. In 283 participants, mGFR were available. Plots of eGFR trajectories illustrated tendencies toward higher eGFR in more recent years; however, this was not confirmed in mGFR trajectories. Poor risk factor control, prior CVD, and male sex impacted mortality and morbidity rates negatively. For men and women with fair risk factor control and no prior CVD, the 10-year mortality rate from onset of DN was 28% and 26%, respectively. For men and women with poor risk factor control and CVD prior to DN onset, the 10-year-mortality rate was 62% for each sex. Conclusion: The results do not support an improved prognosis for T1D and DN, emphasizing the urgent need for new therapeutic approaches.