Renal Transplant Hastalarında Asidozun Kemik Parametreleri Üzerine Etkileri

Abstract

Metabolic acidosis is a common complication after kidney transplantation and is most often caused by renal tubular acidosis (RTA). It is associated with decreased bone mineral density (BMD) and muscle wasting. The aim of our study is to investigate the effect of acidosis, which is one of the factors that can lead to bone loss, in patients who have undergone renal transplantation. 220 patients who were followed up with a diagnosis of kidney transplantation at the HUTF Nephrology outpatient clinic and had BMD measurements were included in our study. Demographic informations, primary renal disease, age at diagnosis, history of pretransplant dialysis, age at transplantation, cadaver or living donor, history of rejection, immunosuppressive drugs regimens and duration of use, cumulative glucocorticoid dose, additional diseases, laboratory features, BMD g/cm2,T-score and Z-score measured by DXA, history of osteoporotic fracture, sinecalcet and vitamin D using were evaluated. Patients were divided into 2 groups: HCO3< 23 mmol/L and HCO3≥ 23 mmol/L. The predictive ability of HCO3 level for osteoporosis and osteopenia was examined by ROC analysis. Univariate and multivariate regression analyzes were applied to determine risk factors associated with osteopenia and osteoporosis. In our study, the average age was 46.2±16.4 years. 51% of the patients were female and 49% were male. The HCO3 value of 48% of the patients was below 23 mmol/L. In the HCO3≥ 23 mmol/L group, the preemptive transplant rate (p=0.001) was significantly higher. In the HCO3≥ 23 mmol/L group, the history of rejection was less (p=0.001). In the HCO3< 23 mmol/L group, the average BUN value was higher (p<0.001), the median creatinine value was higher (p=0.001), the average eGFR value was lower (p<0.001), the average albumin value was lower (p=0.006). Lumbar osteopenia was seen at a significantly higher rate in the HCO3< 23 mmol/L group (p=0.02). Subgroup analysis was performed in patients with eGFR≥60 ml/min/1.73 m2. Lumbar osteopenia (p=0.003), lumbar osteopenia+osteoporosis (p=0.04), femoral osteoporosis (p=0.04), femoral osteopenia+osteoporosis (p=0.03) was seen at a significantly higher rate in the HCO3< 23 mmol/L group. When all patient groups are examined; HCO3 level (AUC: 0.616; p=0.015) was a statistically significant predictor of lumbar osteopenia. The sensitivity of HCO3<23 mmol/L in detecting lumbar osteopenia was 56% and the specificity was 63%. In the analysis performed in patients with eGFR ≥60 ml/min/1.73 m2, HCO3 level (AUC: 0.706; p=0.003) was a statistically significant predictor of lumbar osteopenia. In this group, the sensitivity of HCO3<23 mmol/L in detecting lumbar osteopenia was 70% and the specificity was 68%. In multivariate regression analysis; age (p=0.004), diabetes (p=0.02), hypothyroidism (p=0.01), HCO3<23 mmol/L (p=0.03) were risk factors for lumbar osteopenia. In the multivariate regression analysis performed in patients with eGFR≥60 ml/min/1.73 m2, diabetes (p=0.001), hypothyroidism (p=0.01), HCO3<23 mmol/L (p=0.003) were risk factors for lumbar osteopenia. Metabolic acidosis is one of the factors that causes bone loss after transplantation. In the future, prospective, multicenter studies that include invasive diagnostic methods such as bone biopsy will be effective in revealing possible risks for bone loss after transplantation and determining treatment modalities.