Nomogram analysis of the influencing factors of rapid renal decline in patients with biopsy-proven diabetic nephropathy in type 2 diabetes

HbA1c variability may be related to risk of poor prognoses in chronic kidney disease patients with type 2 diabetes mellitus (T2DM). The aim of this study was to investigate whether HbA1c variability is associated with rapid renal function decline and the related risk factors in type 2 diabetic nephropathy (DN).An observational analysis was performed on 387 DN patients who were diagnosed by kidney biopsy from January 2006 through January 2016 at the Department of Nephrology, Jinling Hospital Affiliated to Nanjing University. The rapid decliners were defined as an estimated glomerular filtration rate (eGFR) decline slope ≥ 5 mL/min/1.73m2/year. HbA1c variability and 24 baseline clinicopathologic parameters was evaluated using the least absolute shrinkage and selection operator regression (LASSO) and multivariate logistic regression. The nomogram method was applied to score the factors, and a scoring model was constructed.HbA1c variability positively correlated with the rate of renal function decline (r = 0.277; p < 0.001). Higher baseline eGFR, lower serum calcium concentration, glomerular lesions, arteriosclerosis, and interstitial fibrosis and tubular atrophy (IFTA) were selected into the nomogram. The calibration curve for the probability of survival showed good agreement between the prediction by nomogram and actual observation. The C-index for predicting survival was 0.811 (95% confidence interval (CI) 0.680 - 0.785).The proposed nomogram and score provide a useful risk estimate of fast renal function decline in patients with type 2 diabetic nephropathy.