Mineral Bone Disorders in Chronic Kidney Disease Stages 3 and 4 With Special Reference to Bone Mineral Density...

Background Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a systemic complication characterized by biochemical disturbances in calcium, phosphate, parathyroid hormone (PTH), and vitamin D metabolism. These abnormalities impair bone strength and promote vascular calcification, increasing fracture and cardiovascular risk. Early CKD stages (3 and 4) provide an opportunity for detection and intervention. Data on Indian pre-dialysis populations remain limited. Objectives This study aimed to describe the clinical and biochemical characteristics of CKD-MBD in patients with CKD stages 3 and 4 and to assess bone mineral density (BMD) using dual-energy X-ray absorptiometry (DEXA) scan. Methodology This single-centre observational cross-sectional study was conducted in the Department of Nephrology, Gauhati Medical College, Guwahati, Assam, India, from May 2024 to April 2025. A total of 130 pre-dialysis CKD patients (Stage 3: n=72; Stage 4: n=58) were enrolled. Baseline demographic variables, comorbidities, clinical presentation, biochemical parameters (serum calcium, phosphate, intact parathyroid hormone (iPTH), 25-hydroxyvitamin D), and lumbar spine and bilateral femoral sites (right and left femur) were assessed using DEXA scan. BMD categories were classified as normal, osteopenia, or osteoporosis according to WHO criteria. A p-value <0.05 was considered statistically significant. Statistical analysis was performed using SPSS software. Results The mean age of the participants was 47.9±14.3 years; 59.2% were men. Compared to Stage 3, Stage 4 patients had significantly higher creatinine (2.86±0.46 vs 1.90±0.29 mg/dL, p<0.001), lower vitamin D (21.4±6.8 vs 32.2±7.6 ng/mL, p<0.0001), higher iPTH (329.7±92.2 vs 274.2±84.1 pg/mL, p=0.0006), and higher phosphate levels (p=0.0011). DEXA revealed lower T-scores in Stage 4 at all sites (p≤0.0004). Osteoporosis prevalence was 44.8% in Stage 4 versus 18.1% in Stage 3 (p=0.0014). Conclusion CKD-MBD begins early in stages 3 and 4, with progressive biochemical derangements and significant bone loss. The study demonstrated an association between advancing CKD stage and lower bone mineral density. While DEXA may aid in bone health assessment in CKD patients, further longitudinal studies are needed to establish its predictive and screening utility.