The effect of vitamin D supplementation on fibroblast growth factor-23 in patients with chronic kidney disease: A systematic review and meta-analysis

This is a meta-analysis of randomized controlled trials (RCTs) investigating the effects of oral vitamin D supplementation on serum fibroblast growth factor-23 (FGF23) concentrations in patients with chronic kidney disease (CKD). Manuscripts were extracted from PubMed/MEDLINE, Scopus, and ISI Web of Science through February 2020. Subgroup analyses, sensitivity analysis, and meta-regression assessments were performed. A total of eight clinical trials with nine treatment arms were included in the final analysis. The pooled results showed no significant changes in circulating FGF23 following vitamin D supplementation compared to the control group (Standardized mean difference (SMD): 0.24; 95% confidence intervals (CIs): -0.03 to 0.50, p > 0.05). Subgroup analyses found that studies which had participants with a body mass index (BMI) higher than 25 kg/m² , with an intervention duration shorter than 15 weeks, using phosphate binder medications, and trials that were on both patients with CKD undergoing hemodialysis and patients without hemodialysis treatment produced significant increases in FGF23 when concentration compared with the control group. This meta-analysis provides evidence that vitamin D supplementation does not have a significant effect on plasma FGF23 levels. However, further high-quality trials are required to identify the influence of oral vitamin D supplementation on FGF23 levels in patients with CKD.

Longitudinal Assessment of PTH in Community-Dwelling Older Women-Elevations Are Not Associated With Mortality

Context:

In older women, the magnitude of elevated parathyroid hormone (PTH) and its consequence is unclear.

Objective:

To describe normal PTH profiles over time and the association with mortality.

Design and Participants:

There were 1044 community-dwelling women in the Malmö Osteoporosis Prospective Risk Assessment cohort (OPRA) who attended baseline (age 75 years). Follow-ups were attended by 715 (age 80 years) and 382 (age 85 years).

Main Outcome Measures:

PTH, estimated glomerular filtration rate (eGFR), 25-hydroxyvitamin D (25OHD) and mortality.

Results:

At age 75 years, PTH levels for most (n = 877, 88%) were within the normal reference range (NRR) (i.e., <6.9 pmol/L). Longitudinally, between ages 75 and 80 years, PTH increased in 60% of all women (n = 390) but increases of up to 50% above baseline values (64%; n=250) still resulted in PTH levels within the NRR. These women had lower 25OHD levels (74 vs 83 nmol/L, P = 0.001). Only when increases were >50% was PTH elevated beyond the NRR (mean 7.1 ± 3.3). Here, a pronounced decline in eGFR (56 vs 61 mL/min/1.73 m², P = 0.002) was found, despite no further changes in 25OHD. Extending the observational period until age 85 years gave similar results. Baseline PTH levels above NRR were associated with mortality (hazard ratio, 1.4; 95% confidence interval (CI), 1.1-1.8; P = 0.007), although not after adjustment for covariates (P = 0.082).

Conclusions:

Most women remained within normal PTH ranges despite large increases of up to 50%. PTH elevated above normal is not independently associated with mortality; impaired kidney function and low 25OHD status may be more prognostic in the very old.

Fabrication of lanthanum-based phosphate binder using cross-linked alginate as a carrier

Lanthanum carbonate loaded sodium alginate cross-linked beads were fabricated and used for phosphate binding.

Prevalence and determinants of parathyroid dysfunction in elderly patients on hemodialysis

BACKGROUND

The goal of this study was to investigate underlying factors of parathyroid dysfunction in elderly patients undergoing maintenance hemodialysis.

METHODS

A total of 286 patients on maintenance hemodialysis were included. Hemoglobin, serum creatinine (Scr), blood urea nitrogen (BUN), serum calcium, serum phosphorus (P), intact parathyroid hormone (iPTH), and serum albumin (Alb) were measured and analyzed both before and after dialysis.

RESULTS

A higher incidence of low iPTH level (<150 pg/l) was observed in the elderly group than that in the non-elderly group (55.8 vs. 36.7%, p < 0.05). Elderly patients had a shorter dialysis duration, lighter dry weight, lower concentrations of BUN, Scr, P, iPTH, Alb and standard protein nitrogen present rate (nPNA) compared to that of non-elderly group patients (p < 0.05).

CONCLUSIONS

Low iPTH level occurs more frequently in elderly hemodialysis patients. Furthermore, age, serum P, serum Alb and nPNA were independently associated with a low iPTH level.

VDRA therapy is associated with improved survival in dialysis patients with serum intact PTH ≤ 150 pg/mL: results of the Italian FARO Survey

BACKGROUND

Chronic kidney disease (CKD) patients affected by mineral bone disorders (MBD) have higher rates of all-cause and cardiovascular-related mortality. Approximately, one-third of dialysis patients have low serum parathyroid hormone (PTH) levels (≤ 150 pg/mL). However, the reason why these patients have higher mortality compared to patients with normal PTH levels has not yet been fully elucidated.

METHODS

The FARO study was performed on 2453 Italian patients followed prospectively from 28 dialysis centres over a 2-year period. Data were collected every 6 months and end points included time-to-death cumulative probability in patients with serum intact PTH (iPTH) ≤ 150 pg/mL and the effect of vitamin D receptor activation (VDRA) therapy. Kaplan-Meier curves and proportional hazards regression models stratified by PTH levels (i.e. ≤ 150 and >150 pg/mL) were used to determine cumulative probability of time-to-death and adjusted hazard ratios (HRs) for demographic, clinical and CKD-MBD treatment characteristics.

RESULTS

The cumulative probability of death was higher (P < 0.01) for patients with serum iPTH levels ≤ 150 pg/mL [25.1%, 95% confidence interval (CI): 22.1-28.5 at 18 months] versus those with serum iPTH levels within the normal range (18.0%, 95% CI: 16.1-20.1). In a model with time-dependent covariates restricted to time periods when patients had iPTH levels ≤ 150 pg/mL, lower mortality was observed in patients treated with VDRA [i.e. HR = 0.62, 95% CI: 0.42-0.92 for oral or intravenous (IV) calcitriol; HR = 0.18, 95% CI: 0.04-0.8 for IV paricalcitol] versus those not receiving any VDRA (P < 0.01) independently of other variables. Patients who received IV paricalcitol, compared with either oral or IV calcitriol, showed reduced mortality, but this was not statistically significant (HR = 0.3, 95% CI: 0.07-1.31, P = 0.11).

CONCLUSION

Results from this observational study suggest that VDRA therapy was associated with improved survival in dialysis patients, even with low serum iPTH levels.