Comparative study of prevalence and predictors of altered bone mineral density in type 2 diabetes mellitus and diabetic kidney disease: A single-center analysis

Background: Diabetes mellitus (DM), particularly type 2 DM (T2DM), is highly prevalent in India and is associated with systemic complications, including chronic kidney disease (CKD) and reduced bone mineral density (BMD). Diabetic kidney disease (DKD), a major microvascular complication of DM, contributes to mineral and bone disorders (CKD) through altered calcium–phosphate metabolism, secondary hyperparathyroidism, and elevated fibroblast growth factor-23 (FGF23). Aim: To compare the prevalence and predictors of altered BMD and bone turnover markers in patients with T2DM and DKD. Materials and Methods: This hospital-based cross-sectional study was conducted over 2 years at a tertiary care center and included 150 participants: 75 with T2DM (without kidney disease) and 75 with DKD. Participants underwent clinical evaluation, laboratory testing (including serum calcium, phosphorus, intact parathyroid hormone (iPTH), 25(OH) Vitamin D, FGF23, and urinary albumin-creatinine ratio), and imaging (dual-energy X-ray absorptiometry scans and renal ultrasonography). DKD diagnosis was based on ADA and Kidney Disease: Improving Global Outcomes 2020 guidelines. Results: DKD patients had significantly worse kidney function (serum creatinine 1.52 ± 0.35 vs. 0.84 ± 0.14 mg/dL; P < 0.001), higher glycated hemoglobin (8.23% vs. 7.75%; P = 0.004), iPTH (117.14 vs. 23.49 pg/mL; P < 0.001), and FGF23 levels (344.10 vs. 62.52 pg/mL; P < 0.001). High bone turnover was noted in 44% of DKD patients versus 0% in DM ( P < 0.001). Surprisingly, spine BMD T-scores were better in DKD (−2.37 vs. −3.14; P = 0.023), while hip BMD showed no significant difference. Serum phosphorus was significantly higher in DKD ( P < 0.001), and Vitamin D levels were lower, nearing significance ( P = 0.058). Conclusion: DKD patients exhibit significantly altered bone mineral metabolism, with higher bone turnover and PTH/FGF23 levels compared to T2DM without nephropathy. These findings underscore the need for integrated renal and skeletal health monitoring in diabetic populations. Larger, multicenter longitudinal studies are warranted to validate these findings and guide management strategies.