Iron-based phosphorus chelator: Risk of iron deposition and action on bone metabolism in uremic rats

Phosphate chelators are frequently used in patients with chronic kidney disease (CKD). New iron-based chelators remain understudied and offer a promising therapeutic option for the control of bone and mineral disorders of chronic kidney disease (BMD-CKD). We assessed the effect of the phosphorus chelator, chitosan-iron III (CH-FeCl), compared to calcium carbonate (CaCO₃) in BMD-CKD and the potential iron overload in uremic rats. Thirty-two animals were divided into four groups, namely the control, CKD, CKD/CH-FeCl, and CKD/CaCO₃ groups. CKD was induced by adding 0.75% (4 weeks) and 0.1% (3 weeks) adenine to the diet. The chelators were administered from week 3 through week 7. The renal function, BMD-CKD markers, and histomorphometry of the femur were assessed at week 7. The CKD group showed a significant increase in creatinine (83.9 ± 18.6 vs. 41.5 ± 22.1 µmol/L; P = 0.001), phosphate (3.5 ± 0.8 vs. 2.2 ± 0.2 mmol/L; P = 0.001), fractional excretion of phosphorus (FEP) (0.71 ± 0.2 vs. 0.2 ± 0.17; P = 0.0001), and FGF23 (81.36 ± 37.16 pg/mL vs. 7.42 ± 1.96; P = 0.011) compared to the control group. There was no accumulation of serum or bone iron after the use of CH-FeCl. The use of chelators reduced the FEP (control: 0.71 ± 0.20; CKD/CH-FeCl: 0.40 ± 0.16; CKD/CaCO₃ 0.34 ± 0.15; P = 0.001), without changes in the serum FGF23 and parathyroid hormone levels. Histomorphometry revealed the presence of bone disease with high remodeling in the uremic animals without changes with the use of chelators. The CH-FeCl chelator was efficient in reducing the FEP without iron accumulation, thereby paving the way for the use of this class of chelators in clinical settings in the future.     

Multilevel Correlates of Non-Adherence in Kidney Transplant Patients Benefitting from Full Cost Coverage for Immunosuppressives: A Cross-Sectional Study

Background

Adherence is the result of the interaction of the macro, meso, micro, and patient level factors. The macro level includes full coverage of immunosuppressive medications as is the case in Brazil. We studied the correlates of immunosuppressive non-adherence in post kidney transplant patients in the Brazilian health care system.

Methods

Using a cross-sectional design, adherence to immunosuppressives was assessed in a sample of 100 kidney transplant patients using a composite non-adherence score consisting of three methods (self-report [i.e., The Basel Adherence Scale for Assessment of Immunossupressives–BAASIS], collateral report, and immunosuppressive blood levels). Multilevel correlations of non-adherence were assessed (macro, meso, micro and patient level). Univariate and multivariate logistic regression was applied to assess the correlates of non-adherence.

Results

Our sample consisted primarily of male (65%), Caucasians (72%) with a mean age of 45.0 ± 13.5 years old, who received grafts from a living donor (89%), with a mean time after transplantation of 72.3 ± 44.4 months. Prevalence of non-adherence was 51%. Family income higher than five reference wages (21.6 vs. 4%; OR 6.46 [1.35–30.89], p = 0.009; patient level), and having access to private health insurance (35.3% vs. 18.4%; OR 2.42 [0.96–6.10], p = 0.04; meso level) were associated with non-adherence in univariate analysis. Only the higher family income variable was retained in the multiple logistic regression model (OR 5.0; IC: 1.01–25.14; p = 0.04).

Conclusions

Higher family income was the only factor that was associated with immunosuppressive non-adherence. In Brazil, lower income recipients benefit from better access to care and coverage of health care costs after transplantation. This is supposed to result in a better immunosuppressive adherence compared to high-income patients who have experienced these benefits continuously.