JCEM: Serum phosphate, a neglected indicator in the clinical treatment of primary hyperparathyroidism

Typical primary hyperparathyroidism (PHPT) is characterized by high parathyroid hormone concentration, high serum and urine calcium content, low serum phosphate (P) concentration, and detection of serum calcium (Ca) level for the diagnosis of PHPT It is very important and is included in the standard of asymptomatic PHPT (aPHPT) surgical treatment recommended by the latest international guidelines together with 24-hour urine calcium (UCa)
.

Serum and urine P levels have nothing to do with the diagnosis of PHPT, nor are they included in the criteria for surgery in PHPT patients

 Typical primary hyperparathyroidism (PHPT) is characterized by high parathyroid hormone concentration, high serum and urine calcium content, low serum phosphate (P) concentration, and detection of serum calcium (Ca) level for the diagnosis of PHPT It is very important and is included in the standard of asymptomatic PHPT (aPHPT) surgical treatment recommended by the latest international guidelines together with 24-hour urinary calcium (UCa)

The two-site immunochemiluminescence assay (Immulite 2000; DPC, Los Angeles, CA) was used to measure the serum intact PTH concentration until 2012, and the inter-assay and intra-assay coefficients of variation were 6.
3% to 8.
8% and 4.
2% to 5.
7%, respectively
.

After 2012, the new second-generation immunochemiluminescence assay (Cobas e411, Roche Diagnostics) was used to measure the serum intact PTH concentration, and the inter-assay and intra-assay coefficients of variation were 3.

The radioimmunoassay (DIAsource 25OHVit) was used to determine the serum 25-hydroxyvitamin D (25OHD) level
.

D3-Ria-CT kit-DIAsource immunoassay (Nivelles, Belgium), the detection limit is 0.

Throughout the study, the same instrument (DXA QDR-4500, Holoch, Bedford, Massachusetts) was used to measure the bone mineral density of the lumbar spine (L2-L4), proximal femur, and distal radius of the non-dominant
.

The slight upgrade of the bone densitometer, especially in terms of reporting and process duration, did not significantly affect the results

All patients underwent a standard renal ultrasound examination, using a 2-5 MHz broadband convex transducer
.

In order to confirm the diagnosis of stones, so that patients can be classified as positive or negative for kidney stones, radiologists look for hyperechoic spots with a diameter of more than 2 mm and perform multi-planar evaluation of specific signs, such as echo, posterior acoustic shadow, or positive Flickering signs

Results: 198/472 patients had P levels lower than 2.
5 mg/dL (HypoP), accounting for 41.
9%
.

Mild (2-2.

The P level of men is lower than that of women .

Table 1 Comparison of P levels (mg/dL) in 472 PHPT patients based on demographic and clinical characteristics

Table 1 Comparison of P levels (mg/dL) in 472 PHPT patients based on demographic and clinical characteristics

Table 2 Comparison of P levels (mg/dL) among PHPT patients subdivided according to demographic and clinical characteristics

Table 2 Comparison of P levels (mg/dL) among PHPT patients subdivided according to demographic and clinical characteristics

Table 3 Comparison of PHPT patients with and without hypophosphatemia

Table 3 Comparison of PHPT patients with and without hypophosphatemia

Table 4 Single-factor correlation analysis of blood phosphorus levels and demographic and clinical parameters in PHPT patients

Table 4 Single-factor correlation analysis of blood phosphorus levels and demographic and clinical parameters in PHPT patients

Conclusion: We observed the relationship between P level and the biochemical and clinical characteristics of PHPT severity
.

In asymptomatic PHPT patients, even moderate HypoP can predict surgical indications regardless of age and severity of hypercalcemia

We observed a relationship between P levels and the biochemical and clinical characteristics of PHPT severity
.
In asymptomatic PHPT patients, even moderate HypoP can predict surgical indications regardless of age and severity of hypercalcemia
.

Original source:

Castellano E, Attanasio R, Boriano A, Pellegrino M, Borretta G, Serum Phosphate: A Neglected Test In The Clinical Management Of Primary Hyperparathyroidism .
J Clin Endocrinol Metab 2021 Sep 14

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