Exploring the Incidence and Risk Factors of Diabetic Nephropathy in Type 1 Diabetes: Insights from a Retrospective Cohort Study in Northwest China

Abstract

Purpose: The study aimed to investigate the incidence of diabetic nephropathy (DN) and their relationship with certain risk factors in patients with type 1 diabetes (T1D) across hospitals in Gansu Province, China.

Methods: There were 434 T1D patients recruited from Gansu Province, China, in the present retrospective cohort study between January 2016 and December 2024. Patients were divided into two groups: (i) patients with T1D but without DN and (ii) type 1 diabetic nephropathy (T1DN). Eligibility for T1DN patients included a T1D diagnosis coupled with urine albumin to creatinine ratio ≥ 30 mg/g. Lifetable method helped determine the cumulative T1DN incidence, and Cox regression helped analyze the associated risk factors. The correlation between predictors (eg, age, serum creatinine (Scr)), and T1DN was assessed with restricted cubic spline curves depending on Cox proportional hazards regression models.

Results: The five-year cumulative incidence of T1DN was 29.89%. T1DN risk factors included diabetic ketosis/ketoacidosis (hazard ratio (HR): 1.623, 95% confidence interval (CI): 1.099-2.454, P =0.015) and high Scr levels (HR: 1.003, 95% CI: 1.001-1.006, P =0.010). However, age (HR: 0.534, 95% CI: 0.306-0.710, P < 0.001) and high-density lipoprotein cholesterol (HDL-C) (HR: 0.528, 95% CI: 0.261-0.851, P =0.013) showed a negative association. Significant relationships were not observed with other variables studied, including hypertension, fasting plasma glucose, and postprandial glucose. The dose-response relationship suggested that age, HDL-C, and Scr levels were non-linearly associated with five-year cumulative DN incidences in patients with T1D.

Conclusion: Younger age and lower HDL-C levels were identified as risk factors for DN in patients with T1D. Additionally, diabetic ketosis/ketoacidosis and elevated Scr levels were associated with increased DN risk. Early diagnosis and treatment of dyslipidemia are warranted in patients with T1D. Furthermore, close monitoring of patients with diabetic ketosis/ketoacidosis or high Scr levels is crucial for DN management in these patients.

Keywords: cumulative incidence; risk factors; type 1 diabetes; type 1 diabetes nephropathy.

Figure 1

Cumulative incidence of type 1 diabetic nephropathy estimated in different groups using the life-table method. (A) Age <18 years (blue line) and age ≥18 years (red line). (B) Patients without (blue line) and with (red line) diabetic ketosis.

Figure 2

Restricted cubic spline (RCS) analysis of the association between predictors and the risk of type 1 diabetic nephropathy. (A) Association between age and the risk of diabetic nephropathy. (B) The relationship with serum creatinine (Scr), and (C) the association with high-density lipoprotein cholesterol (HDL-C). Four knots are placed at the 20th, 40th, 60th, and 80th percentiles of the predictor value range. Solid lines represent the fitted RCS curves, whereas dashed lines indicate the 95% confidence intervals. X-axes represent the continuous predictor variables, and Y-axes represent the relative risk of diabetic nephropathy.