Dynamics of bone mineral disorders in elderly patients with chronic kidney disease

Fractures represent a significant socioeconomic burden worldwide. In chronic kidney disease, the incidence of fractures is five times higher than in the general population, with this disparity being particularly pronounced in advanced stages of renal dysfunction and among elderly patients. Hip fractures are four times more common in dialysis patients compared to the general population. In our prospective study, we analyzed mineral and bone disorder parameters in elderly patients with CKD, assessed FRAX calculator prognostic data in this patient cohort, and identified the most significant predictors of fracture development. The obtained data will be used to finalize the design of an information system for remote assessment of fracture risk over the next three years.

BACKGROUND. Mineral and bone disorders (MBD) are one of the leading complications in elderly patients with chronic kidney disease (CKD).

OBJECTIVE. To assess the three-year dynamics of mineral and bone disorders in patients with chronic kidney disease.

MATERIALS AND METHODS. The study included 50 patients with a mean age of (67.4 ± 1.6) year. For each patient, the 10-year fracture risk was assessed at baseline and after 3 years, along with comprehensive laboratory and instrumental examinations. Statistical analysis was performed using SPSS Statistics 22 software.

RESULTS. The overwhelming majority of patients had CKD stages 3–5 (76 %). The following CKD-MBD manifestations were recorded: secondary hyperparathyroidism, vitamin D deficiency/insufficiency across all CKD stages, and hyperphosphatemia predominantly in CKD5. Three patients had fracture history, 3 women experienced early menopause, and 4 patients received glucocorticoids for >3 months. Diabetes mellitus was the leading comorbidity (n = 21; 42 %). Osteoporosis was present in every third CKD patient (n = 15; 30 %). In the study cohort, 18 patients (n = 18; 36 %) required therapeutic intervention: native and active forms of vitamin D, calcium supplements, phosphate binders, bisphosphonates, and human monoclonal IgG2 antibody. During the three-year follow-up period, 7 patients (n = 7; 14 %) were lost to follow-up due to death: severe internal organ dystrophy resulting from intoxication caused by septic process (n = 1; 2 %), multiple organ failure (n = 3; 6 %), circulatory failure (n = 2; 4 %), and suicide (n = 1; 2 %). Additionally, 8 patients (n = 8; 16 %) experienced low-energy fractures. However, three years earlier, the FRAX scale had predicted fracture development within the next 10 years for only 4 of our patients (n = 4; 8 %). The recorded incidence of osteoporosis also increased by 12 %. Timely initiation of therapy could have prevented fracture development in the study group during the three-year observation period. The performed ROC analysis established the necessity of conducting both FRAX® and bone densitometry in elderly CKD patients, as their combined use enables effective identification of fracture risks and osteoporosis in patients with chronic kidney disease. Furthermore, the obtained results of factor analysis allowed identification of the most significant predictors of fracture development in CKD, while cluster analysis grouped these parameters into distinct categories.

CONCLUSION.

1. Osteoporosis by DXA was detected in every third elderly patient with CKD (n = 15; 30 %).
2. Only 8 % of CKD patients had a high 10-year fracture risk according to FRAX®. The values remained comparable after three years.
3. Despite the low 10-year fracture risk predicted by FRAX®, every sixth CKD patient (n = 8; 16 %) experienced a low-energy fracture during the 3-year follow-up.
4. The obtained data will be used to develop an information system for fracture risk assessment in elderly CKD patients within the next three years.
5. CKD patients require adequate anti-osteoporotic therapy to prevent the onset and progression of MBD.