Plasma D-dimer levels are associated with disease progression in diabetic nephropathy: a two-center cohort study

Background: This study aimed to investigate the relationship between plasma D-dimer levels, clinicopathological features, and clinical outcomes in patients with biopsy-proven diabetic nephropathy (DN).Methods: A total of 137 patients with biopsy-proven DN were enrolled in this two-center cohort study. Patients were stratified into tertiles based on plasma D-dimer levels. We investigated the relationship between plasma D-dimer levels and clinical outcomes, including a composite of death, a 40% decline in estimated glomerular filtration rate (e-GFR) from baseline, or end-stage renal disease (ESRD) (defined as e-GFR < 15 mL/min/1.73 m(2) or need for renal replacement therapy including hemodialysis, peritoneal dialysis, or kidney transplantation), assessed using Cox regression models with adjustment for confounders.Results: At baseline, the mean age was 52.61 +/- 11.63 years, and the mean e-GFR was 58.02 +/- 28.77 mL/min/1.73 m(2). During a median 26-month follow-up period, 65 (47% of patients) achieved clinical outcomes. Compared with the low plasma D-dimer level group, those with higher plasma D-dimer levels were more likely to have higher 24-h proteinuria (p = .002), lower e-GFR (p = .001), lower hemoglobin (p = .001), a higher glomerular lesion class (p = .03), and higher interstitial fibrosis and tubular atrophy (IFTA) scores (p = .002). After adjustment for demographic, DN-specific covariates, and treatments, it was observed that a higher tertile of plasma D-dimer was nonlinearly associated with an increased risk of the clinical outcomes (Hazard Ratio (HR) for tertile 2 vs. 1, 1.7; 95% Confidence Interval (CI), 0.80-3.75; HR for tertile 3 vs. 1, 2.2; 95% CI, 0.93- 5.27; for trend = .001) in the Cox hazards models.Conclusion: In this study, DN patients with higher levels of plasma D-dimer had higher 24-h proteinuria, lower e-GFR, a higher glomerular lesion class, and higher IFTA scores. Furthermore, a high level of plasma D-dimer was nonlinearly associated with DN progression.