Frequent monitoring of mineral metabolism in hemodialysis patients with secondary hyperparathyroidism: associations with achievement of treatment goals and with adjustments in therapy

Abstract

Background: Dialysis guidelines in Japan recommend more frequent measurement of mineral metabolism markers than the Kidney Disease: Improving Global Outcomes guidelines. However, the extent to which frequent marker measurement contributes to achievement of target ranges and to therapy adjustment is unknown. Methods: This multicenter cohort study involved 3276 hemodialysis patients with secondary hyperparathyroidism. Data on laboratory measurements and drug prescriptions were collected every 3 months. Main exposures were frequencies of measuring serum calcium and phosphorus [weekly/biweekly/monthly (reference)] and serum parathyroid hormone (PTH) [monthly/bimonthly/trimonthly (reference)] levels. Outcomes were achievement of guideline-specified ranges of mineral metabolism markers when serum levels were over, and maintenance of ranges when levels were already within, respective specified ranges, use of intravenous vitamin D receptor activator (VDRA) and initiation of cinacalcet use. Associations were examined via generalized estimating equations. Results: When serum marker levels exceeded the target range, weekly measurement of calcium and phosphorus was positively associated with achievement of the guideline-specified calcium range [adjusted odds ratio (AOR): 1.57, 95% confidence interval (CI) 1.09–2.26] but not phosphorus range (AOR: 0.99, 95% CI 0.74–1.33). Monthly measurement of PTH was positively associated with achievement of the guideline-specified PTH range (AOR: 1.14, 95% CI 1.01–1.27). When serum marker levels were within the guideline-specified range, increased frequency of measurements was not associated with in-range maintenance of marker levels for any of the three mineral markers assessed. Regarding treatment regimen, relatively frequent measurement of serum calcium and phosphorus was positively associated with cinacalcet initiation and relatively frequent measurement of serum PTH with cinacalcet initiation and intravenous VDRA use. Conclusions: Our results suggest that increasing frequency of measurements is helpful when serum marker levels exceed the target range, partially via adjustment in the therapeutic regimen. We found no evidence that frequent measurements are helpful when mineral levels are already within target ranges.

The Frequency of Routine Blood Sampling and Patient Outcomes Among Maintenance Hemodialysis Recipients

“…They found no evidence that more frequent measurements were of value when calcium, phosphorus, and PTH were already in target range. 17 Recent work by our group highlighted the stability of target achievement for anemia and CKD-MBD parameters after a de-escalation of blood sampling frequency from monthly to every 6 weeks at a single dialysis program in Ontario. 18 No change in mortality was observed after this change in practice.…”

Algoritmo de diagnóstico y tratamiento del hiperparatiroidismo secundario en la enfermedad renal crónica avanzada

“…Sin embargo, en aquellos pacientes con PTHi elevada y expuestos a intervenciones terapéuticas, la medición mensual (cuatro semanas) de esta hormona se relaciona con un mejor control (Fig. 2) 14 .…”

Chronic Kidney Disease-Mineral and Bone Disorder in Asia

“…Furthermore, routine laboratory tests for Japanese dialysis patients still remain more frequent than those recommended by the KDIGO, even after the bundling of dialysis fees. We analyzed whether such frequent tests were really beneficial and found that among those who had serum parameters above the upper limit of the ranges, more frequent tests were associated with better achievement of the target ranges [41] .…”