Study goal

The main goal of this study was to investigate the consistency with which nephrologists in the US follow KDIGO’s 2017 guidelines on testing and retesting for abnormalities in CKD–MBD analytes, such as elevations in parathyroid hormone (PTH) and reductions in 25-hydroxyvitamin D (25(OH)D).¹

Study design

An analysis was conducted of data from 2010 to 2019 in IBM Explorys, an electronic database with over 50 million US patient health records.¹ After creating cohorts of stage 3, 4 and 5 chronic kidney disease (CKD) patients:¹

1. The ordering of tests related to CKD–MBD abnormalities during follow-up was assessed
2. The incidence of post-treatment retesting was estimated
3. The rates of testing and post-treatment retesting were compared against KDIGO’s CKD–MBD guidelines
4. Predictors of retesting were explored

Study results

The study included large stage 3, 4 and 5 CKD cohorts¹

Table 1 presents the numbers of stage 3, 4 and 5 CKD patients included in the study and their respective mean follow-up.

Table 1. The numbers of stage 3, 4 and 5 CKD patients and their mean follow-up¹

Adapted from Wetmore JB et al. 2021.¹

Testing for CKD–MBD abnormalities was lower than is recommended by KDIGO^1,2

The number of patients tested for CKD–MBD abnormalities was suboptimal, with the lowest number of tests being ordered for PTH, 25(OH)D and phosphorus (Table 2).¹

Table 2. The percentages of stage 3, 4 and 5 CKD patients tested for CKD–MBD abnormalities vs the KDIGO testing guidelines^1,2

^†Frequency determined by baseline level and CKD progression.^{2 ‡}Frequency determined by baseline level and therapeutic interventions.^{2 §}More frequently in the presence of elevated PTH.²

Adapted from Wetmore JB et al. 2021¹ and KDIGO Work Group 2017.²

Post-treatment retesting of PTH, 25(OH)D and phosphorus was lower than is recommended by KDIGO^1,2

The patterns of post-treatment retesting of PTH, 25(OH)D and phosphorus are presented in Table 3 and once again reflect suboptimal adherence levels.¹

Table 3. Patterns of post-treatment retesting of PTH, 25(OH)D and phosphorus in stage 3, 4 and 5 CKD patients vs the KDIGO testing guidelines^1,2

^¶Frequency determined by baseline level and therapeutic interventions.^{2 ǁ}Ergocalciferol or cholecalciferol.² **Frequency determined by baseline level and CKD progression.^{2 ††}For example, calcitriol, paricalcitol or doxercalciferol.¹

Adapted from Wetmore JB et al. 2021¹ and KDIGO Work Group 2017.²

Few effective predictors of post-treatment retesting were identified¹

Although female gender appeared to be associated with a lower rate of phosphorus retesting, age, sex and race were generally not associated with retesting of PTH, 25(OH)D and phosphorus.¹

The rate of retesting of phosphorus appeared to increase in a dose-response fashion according to the pretreatment phosphorus level.¹ Pretreatment levels of PTH and 25(OH)D were not associated in a graded fashion with the likelihood of post-treatment retesting, as they would have been if KDIGO’s guidelines had been followed.¹

Key takeaways

• Rates of testing and post-treatment retesting for CKD–MBD-related abnormalities were lower than is recommended by KDIGO¹
• In the cases of PTH and 25(OH)D, pretreatment levels were not associated with the likelihood of post-treatment retesting¹
• By suboptimally adhering to KDIGO guidelines, nephrologists are missing opportunities to treat CKD–MBD abnormalities, which leaves room for the potential development of serious bone and cardiovascular complications^3,4

To read the full paper by Wetmore et al., please refer to the Kidney International Reports website.

For a summary of KDIGO’s guidelines on CKD–MBD management, download our KDIGO CKD–MBD Quick Reference Guide, accessible via the Download page.

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