Early identification of risk factors for refractory secondary hyperparathyroidism in patients with long-term renal replacement therapy

Prognosis and factors related to severe secondary hyperparathyroidism in long-term peritoneal dialysis patients

Secondary hyperparathyroidism (SHPT) can progress to severe SHPT (sSHPT), which affects the survival rate and quality of life of patients. This retrospective cohort study investigated risk factors for sSHPT and the association between SHPT and mortality (all-cause and infection-related) among 771 clinically stable patients (421 male patients; mean age, 51.2 years; median dialysis vintage, 28.3 months) who underwent >3 months of regular peritoneal dialysis (PD) between January 2013 and March 2021. The sSHPT and non-sSHPT groups comprised 75 (9.7%) (median progression, 35 months) and 696 patients, respectively. sSHPT was defined as a serum intact parathyroid hormone (PTH) level >800 pg/mL observed three times after active vitamin D pulse therapy. The influence of sSHPT on the prognosis of and risk factors for sSHPT progression were evaluated using logistic and Cox regression analyses. After adjusting for confounding factors, higher (each 100-pg/mL increase) baseline PTH levels (95% confidence interval (CI) 1.206-1.649, p < .001), longer (each 1-year increase) dialysis vintages (95% CI 1.013-1.060, p = .002), higher concomitant diabetes rates (95% CI 1.375-10.374, p = .010), and lower (each 1-absolute unit decrease) Kt/V values (95% CI 0.859-0.984, p = .015) were independent risk factors for progression to sSHPT in patients on PD. During follow-up, 211 deaths occurred (sSHPT group, n = 35; non-sSHPT group, n = 176). The sSHPT group had significantly higher infection-related mortality rates than the non-sSHPT group (12.0% vs. 4.3%; p < .05), and sSHPT was associated with increased infection-related mortality. In conclusion, patients with sSHPT are at higher risk for death and infection-related mortality than patients without sSHPT.

Shear Wave Elastography in Diagnosing Secondary Hyperparathyroidism

This study evaluates the diagnostic value of two-dimensional shear wave elastography (2 D-SWE) technique in the evaluation of hyperplastic parathyroid glands in cases with secondary and tertiary hyperparathyroidism. A total of 59 patients (end-stage renal disease, under supplemental dialysis program) with visible parathyroid hyperplastic glands on ultrasound, confirmed by biochemical assay and scintigraphy, were enrolled; they were examined on grayscale ultrasound and 2 D shear wave elastography. We determined the elasticity index (EI) in the parathyroid gland, thyroid parenchyma and surrounding muscles, and the elasticity ratio of hyperplastic parathyroid glands compared to muscle, specifically sternocleidomastoid muscle. Patients presented fibrocystic bone disease with secondary hyperparathyroidism induced by end-stage chronic kidney disease; being on prolonged chronic dialysis therapy, they had positive sestamibi scintigraphy and high values of serum parathormone (1141.04 pg/mL). Nodules placed posterior to the thyroid capsule that were cystic, had a hypoechoic aspect, and were homogenous with an independent afferent artery were found. Mean EI in the parathyroid gland was 7.83 kPa, the median value in thyroid parenchyma was 13.76 kPa, and mean muscle EI value was 15.78 kPa. The observed mean parathyroid/muscle SWE ratio was 0.5356 and the value for parathyroid/normal thyroid parenchyma was 0.5995. Using receiver operating characteristic (ROC) analysis, we found that EI below 9.74 kPa correctly identifies parathyroid tissue, with a sensitivity of 94.8%, specificity of 90.7%, and accuracy of 92.26% when compared to normal thyroid tissue. Compared with the muscle tissue, we identified that EI below 9.98 kPa has a sensitivity, specificity, and accuracy of 93.8%, 90.7%, and 91.75%, respectively. Ultrasound elastography is a helpful tool in identifying parathyroid hyperplasia in patients with chronic kidney disease. A cutoff value of 9.98 kPa can be used in 2 D-SWE for accurate diagnosis of parathyroid disease.

Influence of Parathyroidectomy on Bone Metabolism and Bone Pain in Patients with Secondary Hyperparathyroidism

BACKGROUND

After parathyroidectomy (PTX), hungry bone syndrome leads to hypocalcemia due to bone remineralization. The aim of this pilot study was to analyze changes in markers of bone metabolism in patients with secondary hyperparathyroidism (sHPT) after PTX and to correlate these markers with bone pain measured with a validated questionnaire.

MATERIALS AND METHODS

All patients who underwent PTX for sHPT between March 2010 and February 2012 at out institution were included in this prospective observational pilot study. At the day before surgery and on the 3rd day thereafter, levels of parathyroid hormone (PTH), calcium, osteocalcin, alkaline phosphatase (AP), bone-specific AP (BAP), tartrate-resistant acid phosphatase 5b (TRAP5b), osteoprotegerin (OPG), sclerostin, fibroblast growth factor 23, and Klotho were measured. Additionally, all patients were requested to answer the Brief Pain Inventory preoperatively and on the 5th postoperative day.

RESULTS

A total of 35 patients with a mean age of 49.8 years were analyzed. A significant difference between the pre- and postoperative values could be detected in PTH, calcium, BAP, TRAP5b, and sclerostin. The highest correlation of laboratory markers with bone pain was found for preoperative PTH (r = 0.3), postoperative OPG (r = 0.4), postoperative BAP (r = -0.4), and postoperative Klotho (r = -0.4).

CONCLUSIONS

The present study revealed significant perioperative changes in PTH, BAP, sclerostin, and TRAP5b after PTX. These markers may serve as laboratory markers to monitor bone metabolism in patients with sHPT. PTH, OPG, and sclerostin were the parameters with the closest correlation to bone pain. However, larger prospective trials with a longer follow-up are required to confirm these results.

Roles of Serum Calcium, Phosphorus, PTH and ALP on Mortality in Peritoneal Dialysis Patients: A Nationwide, Population-based Longitudinal Study Using TWRDS 2005-2012

Biomarkers of chronic kidney disease-mineral and bone disorder (CKD-MBD) correlate with morbidity and mortality in dialysis patients. However, the comparative roles of each CKD-MBD biomarker remained undetermined on long-term peritoneal dialysis (PD) patients. This retrospective study, employing a population-based database, aimed to evaluate the performance and provide the best evidence of each biomarker of CKD-MBD as predictor of all-cause mortality. Throughout the 8-year study period, total 12,116 PD patients were included in this study. Cox proportional regression and Kaplan-Meier method were used for survival analysis. For Cox regression model, baseline measurements and time-varying covariates were used for analysis. In Cox regression model using time-dependent covariates, serum calcium level of ≧9.5 mg/dL was associated with increased mortality. For phosphorus, serum levels of either ≧6.5 mg/dL or <3.5 mg/dL were associated with increased mortality. For parathyroid hormone (PTH), higher serum levels were not associated increased mortality. For alkaline phosphatase (ALP), mortality increased at levels ≧100 IU/L. Our findings suggested that the detrimental effect of ALP on survival was more consistent, while serum calcium, phosphorus and PTH may have a less prominent effect on mortality. This study provided additional information for manipulating CKD-MBD biomarkers in PD patients.

Evaluation of Parathyroidectomy for Secondary and Tertiary Hyperparathyroidism by the Parathyroid Surgeons' Society of Japan

Secondary hyperparathyroidism (SHPT) remains a serious complication in patients with chronic kidney disease, and some patients require parathyroidectomy. The Parathyroid Surgeons' Society of Japan (PSSJ) evaluated parathyroidectomy for SHPT and tertiary hyperparathyroidism (THPT) in Japan. The annual numbers of parathyroidectomies between 2004 and 2013 were evaluated using questionnaires. Since 2010, the PSSJ has registered the patients. In total, 826 patients from 42 institutions were registered. The annual number of parathyroidectomies for SHPT and THPT in Japan increased from 2004 to 2007 and then decreased markedly after 2007, with 296 operations performed in 2013. The number of women and men was almost equal (397/427). Median (interquartile range) age of these patients was 59.0 (24-87) years, the duration of hemodialysis before parathyroidectomy was 10.83 (0.0-38.7) years, and diabetic nephropathy was 87/826 (10.5%). Of these patients 59.6% were treated with cinacalcet at undergoing parathyroidectomy. In 75.3% of patients, a total parathyroidectomy with forearm autograft was performed. In 77.7% of patients, four or more parathyroid glands were removed during the initial operation. The incidences of husky voice and wound hemorrhage were 2.9% and 1.1%, respectively. The number of parathyroidectomies for SHPT in Japan decreased markedly after the introduction of cinacalcet. Based on the evaluation of registered patients, parathyroidectomies have been successfully performed at the institutions participating in the PSSJ.

Medical and Surgical Treatment for Secondary and Tertiary Hyperparathyroidism

Prevention and treatment of secondary hyperparathyroidism (SHPT) in patients on chronic maintenance hemodialysis and of tertiary hyperparathyroidism (THPT) in patients after kidney transplantation is a challenge for the nephrologist and for the surgeon. Indication and results of medical and surgical therapy for SHPT and THPT have remained under discussion during the last decades. This review resumes the current medical and surgical strategies for patients with SHPT and THPT.

Parathyroidectomy Associates with Reduced Mortality in Taiwanese Dialysis Patients with Hyperparathyroidism: Evidence for the Controversy of Current Guidelines

Parathyroidectomy is recommended by the clinical guidelines for dialysis patients with unremitting secondary hyperparathyroidism (SHPT). However, the survival advantage of parathyroidectomy is debated because of the selection bias in previous studies. To minimize potential bias in the present nationwide cohort study, we enrolled only dialysis patients who had undergone radionuclide parathyroid scanning to ensure all patients had severe SHPT. The parathyroidectomized patients were matched with the controls based on propensity score for parathyroidectomy. Mortality hazard was estimated using multivariate Cox proportional hazard models adjusting for comorbidities before scanning (model 1) or over the whole study period (model 2). Our results showed that among the 2786 enrolled patients, 1707 underwent parathyroidectomy, and the other 1079 were controls. The crude mortality rates were lower in the parathyroidectomized patients than in the controls. In adjusted analyses for the population matched on propensity score, parathyroidectomy was associated with a significant 20% to 25% lower risk for all-cause mortality (model 1: hazard ratio 0.76, 95% confidence interval 0.61 to 0.94; model 2: hazard ratio 0.80, 95% confidence internal 0.64 to 0.98). We concluded that parathyroidectomy was associated with a reduced long-term mortality risk in dialysis patients with severe SHPT.

Associations between renal hyperfiltration and serum alkaline phosphatase

Renal hyperfiltration, which is associated with renal injury, occurs in diabetic or obese individuals. Serum alkaline phosphatase (ALP) level is also elevated in patients with diabetes (DM) or metabolic syndrome (MS), and increased urinary excretion of ALP has been demonstrated in patients who have hyperfiltration and tubular damage. However, little was investigated about the association between hyperfiltration and serum ALP level. A retrospective observational study of the 21,308 adults in the Korea National Health and Nutrition Examination Survey IV-V databases (2008–2011) was performed. Renal hyperfiltration was defined as exceeding the age- and sex-specific 97.5^th percentile. We divided participants into 4 groups according to their estimated glomerular filtration rate (eGFR): >120, 90–119, 60–89, and <60 mL/min/1.73 m². The participants with eGFR >120 mL/min/1.73 m² showed the highest risk for MS, in the highest ALP quartiles (3.848, 95% CI, 1.876–7.892), compared to the lowest quartile. Similarly, the highest risk for DM, in the highest ALP quartiles, was observed in participants with eGFR >120 ml/min/1.73 m² (2.166, 95% CI, 1.084–4.329). ALP quartiles were significantly associated with albuminuria in participants with eGFR ≥ 60 ml/min/1.73m². The highest ALP quartile had a 1.631-fold risk elevation for albuminuria with adjustment of age and sex. (95% CI, 1.158-2.297, P = 0.005). After adjustment, the highest ALP quartile had a 1.624-fold risk elevation, for renal hyperfiltration (95% CI, 1.204–2.192, P = 0.002). In addition, hyperfiltration was significantly associated with hemoglobin, triglyceride, white blood cell count, DM, smoking, and alcohol consumption (P<0.05). The relationship between serum ALP and metabolic disorders is stronger in participants with an upper-normal range of eGFR. Higher ALP levels are significantly associated with renal hyperfiltration in Korean general population.

Influence of the use of phosphate binders on serum levels of calcium phosphate in patients with chronic kidney disease undergoing hemodialysis: A retrospective and prospective study

Hypercalcemia-hyperphosphatemia is an unavoidable consequence of end-stage chronic kidney disease and common in hemodialytic patients. Calcium carbonate (CaCO3) is one type of phosphate binder used widely and prescribed in patients undergoing hemodialysis, aiming to control the levels of calcium and phosphate. These drugs are most effective if taken with meals. This study aimed to evaluate the use of phosphate binders in hemodialysis patients and the factors that influence the success of phosphate binder therapy by experimental studies with retrospective data collection through the medical records and prospectively through the questionnaire and interviews with patients. The research was conducted in the Unit Hemodialysis building floor 8 of Cipto Mangunkusumo Hospital, Jakarta. The data were collected in a retrospective way for two months (January-February 2013) and a prospective study in March-April 2013. Patients included were stage 5 chronic kidney disease patients who underwent hemodialysis in hemodialysis ward of Cipto Mangunkusumo Hospital. Patients who had data of serum levels at the beginning of the use of calcium phosphate and the final data in 2013 got the phosphate binder therapy.

RESULTS

Ninety six patients with stage 5 chronic kidney disease who underwent hemodialysis had been using phosphate binder for 3 years in average. Patient evaluation showed that hypocalcemia was obtained in 23%; normokalemia in 42.7% and hypercalcemia in 34.3%. While the percentage of patients with hipofosfatemia14, 6%, normofosfatemia 32.3% and 53.1% hyperphosphatemia. Results obtained by the prospective analysis of factors that affect the success of the use of phosphate binder therapy are related to how the routine use of phosphate binders is made by the patient. Chi square test showed a significance of 0.000 (p < 0.05), the effect of 54%.

CONCLUSION

We can conclude there are many events happening such as hyperphosphatemia in hemodialysis patients that use phosphate binders. Monitoring of serum levels of calcium phosphate in patients with chronic kidney disease undergoing hemodialysis should be performed every month. Education and the role of clinical staff required to assist compliance and therapeutic efficacy of phosphate binder are necessary.

Removal of autografted parathyroid tissue for recurrent renal hyperparathyroidism in hemodialysis patients

BACKGROUND

Recurrent renal hyperparathyroidism (HPT) is a serious problem after parathyroidectomy (PTx). We evaluated the frequency of graft-dependent recurrent HPT and the clinical outcomes after removal of the autograft.

METHODS

Between March 1980 and January 2009, 2660 patients underwent total PTx with forearm autograft. After resection of all parathyroid glands, 30 pieces of 1 x 1 x 3 mm parathyroid tissue from diffuse hyperplasia, if possible, were autografted into brachioradial muscle. Graft-dependent recurrence of HPT was diagnosed by a high PTH gradient and detection of swollen autografts by palpation and/or MRI or US.

RESULTS

In 248/2660 (9.3%) patients, removal of the graft was required a total of 327 times (53 patients required removal of the autograft several times). The cumulative frequency of graft-dependent recurrent HPT was 17.4% ten years after the initial PTx. Thirty-two patients underwent both resection of missed glands located in the neck or mediastinum and removal of the graft. En-bloc resection of autograft with surrounding muscle was required to avoid reoperation. When the intact PTH level dropped under 300 pg/ml, in the majority of patients renal HPT could be medically managed after the operation. The mean weight of the resected parathyroid tissue was 1583.7 mg. No specimen had histopathologically malignant features. Three patients suffered from hematoma in the wound.

CONCLUSIONS

Graft-dependent recurrent renal HPT is not negligible. However, in the majority of patients, renal HPT can be controlled by removal of the autograft noninvasively. Total PTx with forearm autograft is preferable for hemodialysis patients, especially when long-term survival is expected.

High alkaline phosphatase levels in hemodialysis patients are associated with higher risk of hospitalization and death

We evaluated risks associated with elevated alkaline phosphatase in hemodialysis patients using longitudinal data from the Dialysis Outcomes and Practice Patterns Study, a prospective observational study of hemodialysis patients in 12 countries. Alkaline phosphatase levels were normalized by the upper limit of the laboratory-reported reference range. Cause-specific hospitalization and mortality risks were evaluated using Cox proportional hazards models, stratified by region and adjusted for phosphorus, calcium, albumin, parathyroid hormone, case mix, and numerous comorbidities. The odds of high normalized alkaline phosphatase were increased twofold in the United States in comparison to Japan. Elevations of normalized alkaline phosphatase were significantly associated with several comorbid conditions, increased fractures, parathyroidectomy, risk of hospitalization due to major adverse cardiac events, higher all-cause cardiovascular, and infection-related mortality risk. Our results also show that elevated serum normalized alkaline phosphatase was associated with higher risks of hospitalization and death in hemodialysis patients, independent of calcium, phosphorus, and parathyroid hormone levels.

Utility of an intraoperative gamma probe in the surgical management of secondary or tertiary hyperparathyroidism

BACKGROUND

In primary hyperparathyroidism the gamma probe is effective, but its role in secondary hyperparathyroidism is unclear. We investigated the utility of the probe in the surgical management of secondary and tertiary hyperparathyroidism.

METHODS

The value of the probe in guiding resection of parathyroids was determined prospectively in 29 patients with secondary or tertiary hyperparathyroidism. Resected tissues with radioactivity of greater than 20% as compared with the wound bed was considered hyperfunctional parathyroid and was confirmed histologically.

RESULTS

The probe was helpful in guiding resection in 13% of the hyperplastic glands, including ectopic glands and those not detected preoperatively. The gamma probe confirmed the presence of hyperfunctional parathyroid after resection with a sensitivity and specificity of 97% and 92%, respectively.

CONCLUSIONS

The probe is particularly useful in confirming the presence of hyperfunctional parathyroids after resection. It also is useful in identifying ectopic localizations, but its value is limited in guiding surgery for secondary or tertiary disease.