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Learn how PTH levels before dialysis affect PTH control during dialysis

17 October 2020

What is the relationship between the PTH level before dialysis and the risk of refractory SHPT during the first year of dialysis?

According to new data published by Dr Nahid Tabibzadeh* and colleagues, levels of parathyroid hormone (PTH) prior to initiation of dialysis predict PTH levels and therapeutic strategies during the first year of dialysis.1 A summary of the findings and a link to the full journal article are provided below.

Study goal

Optimal control of secondary hyperparathyroidism (SHPT) during non-dialysis chronic kidney disease (ND-CKD) may reduce the risk of parathyroid gland hyperplasia and associated resistance to SHPT therapy during dialysis.1–4 However, the evidence for optimal PTH targets and therapeutic strategies in ND-CKD patients is weak.1

The goal of this study by Dr Nahid Tabibzadeh and colleagues, first published online in the journal Nephrology Dialysis Transplantation in October, 2020, was to investigate the relationships between PTH levels prior to initiating dialysis and patient characteristics, treatment patterns and PTH control during the first year of dialysis.1

Study design

Dr Tabibzadeh and colleagues evaluated data from phases 4 to 6 (2009 to 2018) of the Dialysis Outcomes and Practice Patterns Study (DOPPS), a multiphase prospective cohort study of patients ≥18 years old who were treated with in-centre haemodialysis in 21 countries.1 They began by stratifying 5,683 incident dialysis patients into seven groups by PTH level, measured immediately prior to initiation of dialysis.1 The groups were less than 50 (5%), 50 to 100 (9%), 100 to 150 (9%), 150 to 300 (30%), 300 to 450 (19%), 450 to 600 (11%) and greater than 600 (16%) pg/mL.†1 The researchers then explored the monthly prevalence of active vitamin D (AVD) and calcimimetics prescriptions over the first year of dialysis, along with the risk of having a PTH level greater than 600 pg/mL after 9 to 12 months of dialysis.1

Results

Compared with the 30% of patients who were initiated on dialysis with a PTH between 150 and 300 pg/mL, the 16% who were initiated on dialysis with a PTH greater than 600 pg/mL:1

  • Were more likely to have a PTH greater than 600 pg/mL 9 to 12 months after initiating dialysis despite receiving more aggressive management during dialysis
  • Were more likely to be prescribed AVD and calcimimetics during the first year of dialysis
  • Had lower serum 25-hydroxyvitamin D (25D) levels before initiation of dialysis
  • Had higher serum phosphate and total alkaline phosphatase levels before initiation of dialysis
  • Were younger and more likely to be black

The risk of having a PTH greater than 600 pg/mL 9 to 12 months after initiation of dialysis was 29% for patients who were initiated on dialysis with a PTH greater than 600 pg/mL and only 7% for patients who were initiated on dialysis with a PTH between 150 and 300 pg/mL.1 The adjusted risk difference between the two patient groups was 19%, demonstrating a robust association.1

A summary of the study is provided in the shareable infographic below.

infographic

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Key takeaways

Based on these results, Dr Tabibzadeh and colleagues concluded that:1

  • A high PTH prior to initiation of dialysis is a major risk factor of having a high PTH 9 to 12 months after initiating dialysis, despite greater use of AVD and calcimimetics
  • Earlier control of PTH and bone and mineral parameters, such as phosphate and 25D, may influence outcomes during dialysis
  • Earlier control of PTH may also help to reduce costs during dialysis by reducing the requirement of PTH-lowering medications

You can read the full article published by Dr Tabibzadeh and team right now on the Nephrology Dialysis Transplantation website.

 

Footnotes and references

*Renal Physiology Department, APHP Hôpital Bichat, Université de Paris; Paris, France.

To convert pg/mL to pmol/L, multiply by 0.106.5

 

1. Tabibzadeh N et al. Nephrol Dial Transplant. 2021;36(1):160–9.

2. Rodriguez M et al. Am J Renal Physiol. 2005;288:F253–64.

3. Fukuda N et al. J Clin Invest. 1993;92:1436–43.

4. Gogusev J et al. Kidney Int. 1997;51:328–36.

5. Kidney Disease: Improving Global Outcomes (KDIGO) Work Group. Kidney Int. 2009;76(Suppl. 113):S1–S130.