25(OH)D level and vascular lesion scores in kidney histopathology as risk-stratification tool for predicting renal progression in people with type 2 diabetes.

Aim: To evaluate the potential of the combined individual vascular histopathological lesion and serum 25-hydroxy vitamin D [25(OH)D] level as predictors of outcomes in patients with diabetes and chronic kidney disease.

Methods: A total of 190 patients with type 2 diabetes and kidney disease stages 1-4 were retrospectively included. Kaplan-Meier analysis and the log-rank test were performed to assess renal survival differences. And the time-dependent receiver operating characteristic analyses were used to characterize the predictive accuracy. Hazard ratios for vascular lesion scores and 25(OH)D levels with renal outcomes were estimated using Cox proportional hazards regression models with follow-up time.

Results: Over a median follow-up of 23.78 (12.61, 37.14) months, 71 patients (37.4 %) experienced the renal outcomes. Enrolled patients with more severe vascular lesions had worse kidney function, heavier proteinuria, lower serum 25(OH)D levels, and higher prevalence of composite kidney outcomes. Baseline serum 25(OH)D was a significant independent risk factor for vascular lesion scores. The effect of serum 25(OH)D level on kidney prognosis was more pronounced in males and those with more exacerbated vascular lesions (score 2). The severity of vascular lesions and serum 25(OH)D levels were associated with unfavorable kidney outcomes. Accordingly, further time-dependent receiver operating characteristic curves confirmed that combined 25(OH)D level and vascular lesion score had a stable and reliable performance in renal outcomes prediction at short and long-term follow-up times.

Conclusions: 25(OH)D level and vascular lesion scores in kidney histopathology could serve as a useful risk-stratification tool for predicting renal progression in patients with type 2 diabetes.