A high body mass index and female gender are associated with an increased risk of nodular hyperplasia of parathyroid glands in chronic uraemia

Parathyroidectomy reduces the costs of medication in patients with secondary hyperparathyroidism

INTRODUCTION

Subtotal Parathyroidectomy (S-PTx) and total Parathyroidectomy with immediate Autograft (PTx-AG) are well-established techniques for the treatment of refractory Secondary Hyperparathyroidism (SHPT), with comparable improvements in patients' quality of life and survival. However, the long-term costs after these operations may impact the choice of surgical technique. The objective of the study is to analyze the impact of surgical treatment on medication costs and whether there is any difference between medication use after each procedure, considering impacts on the health system.

MATERIAL AND METHODS

Prospective and randomized study in patients with severe SHPT undergoing S-PTx and PTx-AG. Analysis of prescribed medication costs in the month before the postoperative period at 1-, 3-, 6-, 12-, and 18 months. Costs were estimated according to government payment system values. The medications of 65 patients after PTx-AG were compared with those of 24 patients after S-PTx. A comparison of the total costs of the period between 38 men and 51 women was also made.

RESULTS

There were 89 evaluable cases. Surgery reduced medication costs after 12 months. The median of total drug costs in the analyzed period was R$ 8,375.00 per patient. There was no difference in costs per patient in the S-PTx group compared to the PTx-AG group. The median total costs were R$ 11,063.0 for men and R$ 7,651.0 for women (p = 0.0078).

CONCLUSIONS

The type of parathyroidectomy did not impact costs after surgery. In the first year after surgery, the use of calcium and calcitriol was more significant than the use of other medications. In the following months, the use of sevelamer is responsible for the highest costs. Men have higher costs in outpatient follow-up after surgery.

Sex-Based Differences in Risk Factors and Complications of Chronic Kidney Disease

Globally, females are ∼30% more likely to have pre-dialysis chronic kidney disease (CKD) than males for reasons that are not fully understood. CKD is associated with numerous adverse health outcomes which makes understanding and working to eradicating sex based disparities in CKD prevalence essential. This review maps both what is known, and what is unknown, about the way sex and gender impacts (1) the epidemiology and risk factors for CKD including age, diabetes, hypertension, obesity, smoking, and cerebrovascular disease, and (2) the complications from CKD including kidney disease progression, cardiovascular disease, CKD mineral and bone disorders, anaemia, quality-of-life, cancer and mortality. This mapping can be used to guide future research.

Is There a Gender Difference in Clinical Presentation of Renal Hyperparathyroidism and Outcome after Parathyroidectomy?

Introduction

Gender has been proven to influence the pathophysiology and treatment of numerous diseases, including kidney diseases and hormonal dysfunction like hyperparathyroidism. Thus, higher parathormone levels have been demonstrated in women with end-stage kidney disease, when compared to men.

Objectives

We questioned whether female gender is associated with an increased risk for parathyroid nodular hyperplasia and necessary parathyroidectomy in dialysis patients and assessed demographics as well as outcome data for women and men undergoing parathyroidectomy for renal hyperparathyroidism.

Patients and Methods

One hundred and thirty patients (men = 75, female = 55) with end-stage renal disease on chronic dialysis and advanced secondary hyperparathyroidism who underwent parathyroidectomy between 2008 and 2014 at our center were analyzed retrospectively. Perioperative characteristics and short-term outcome were evaluated with respect to biological gender.

Results

No differences could be demonstrated for patient demography, comorbidities and the perioperative course between males and females. Only preoperative calcium levels were lower in female than in male patients (2.3 ± 0.19 vs. 2.3 ± 0.26, p = 0.04). There were more women, however, with cerebrovascular complications during follow-up (p = 0.04). There was no postoperative mortality, and all complications and comorbidities with exception of cerebrovascular diseases were equally distributed between female and male patients.

Conclusion

Overall, we could not demonstrate many significant differences between male and female patients with end-stage renal diseases, chronic dialysis and operated secondary hyperparathyroidism. Only preoperative electrolyte levels were higher in male than in female patients, and cerebrovascular complications developed more often in females than in males during long-term follow-up.

Personalized Management of Bone and Mineral Disorders and Precision Medicine in End-Stage Kidney Disease

Chronic kidney disease mineral bone disorder (CKD-MBD) is common in end-stage renal disease and is associated with an increased risk of cardiovascular morbidity and mortality. Mainstays of treatment include decreasing serum phosphorus level toward the normal range with dietary interventions and phosphate binders and treating increased parathyroid hormone levels with activated vitamin D and/or calcimimetics. There is significant variation in serum levels of mineral metabolism markers, intestinal absorption of phosphorus, and therapeutic response among individual patients and subgroups of patients with end-stage renal disease. This variation may be partly explained by polymorphisms in genes associated with calcium and phosphorus homeostasis such as the calcium-sensing receptor gene, the vitamin D-binding receptor gene, and genes associated with vascular calcification. In this review, we discuss how personalized medicine may be used for the management of CKD-MBD and how it ultimately may lead to improved clinical outcomes. Although genetic variants may seem attractive targets to tailor CKD-MBD therapy, complete understanding of how these polymorphisms function and their clinical utility and applicability to personalized medicine need to be determined.

Risk-factors for nodular hyperplasia of parathyroid glands in sHPT patients

Introduction

Nodular hyperplasia of parathyroid glands (PG) is the most probable cause of medical treatment failure in secondary hyperparathyroidism (sHPT). This prospective cohort study is located at the interface of medical and surgical consideration of sHPT treatment options and identifies risk-factors for nodular hyperplasia of PG.

Material and methods

One-hundred-eight resected PG of 27 patients with a broad spectrum of sHPT severity were classified according to the degree of hyperplasia by histopathology. Twenty routinely gathered parameters from medical history, ultrasound findings of PG and laboratory results were analyzed for their influence on nodular hyperplasia of PG by risk-adjusted multivariable binary regression. A prognostic model for non-invasive assessment of PG was developed and used to weight the individual impact of identified risk-factors on the probability of nodular hyperplasia of single PG.

Results

Independent risk-factors for nodular hyperplasia of single PG were duration of dialysis in years, PG volume in mm³ determined by ultrasound and serum level of parathyroid hormone in pg/mL. Multivariable analyses computed a model with an Area Under the Receiver Operative Curve of 0.857 (95%-CI:0.773–0.941) when predicting nodular hyperplasia of PG. Theoretical assessment of risk-factor interaction revealed that the duration of dialysis had the strongest influence on the probability of nodular hyperplasia of single PG.

Conclusions

The three identified risk-factors (duration of dialysis, PG volume determined by ultrasound and serum level of parathyroid hormone) can be easily gathered in daily routine and could be used to non-invasively assess the probability of nodular hyperplasia of PG. This assessment would benefit from periodically collected data sets of PG changes during the course of sHPT, so that the choice of medical or surgical sHPT treatment could be adjusted more to the naturally changing type of histological PG lesion on an individually adopted basis in the future.

Negative association between serum parathyroid hormone levels and urinary perchlorate, nitrate, and thiocyanate concentrations in U.S. adults: the National Health and Nutrition Examination Survey 2005-2006

OBJECTIVES

Perchlorate, nitrate, and thiocyanate are well-known inhibitors of the sodium-iodide symporter and may disrupt thyroid function. This exploratory study investigated the association among urinary perchlorate, nitrate, and thiocyanate concentrations and parathyroid hormone (PTH) levels in the general U.S. population.

METHODS

We analyzed data on 4265 adults (aged 20 years and older) from the National Health and Nutrition Examination Survey in 2005 through 2006 to evaluate the relationship among urinary perchlorate, nitrate, and thiocyanate concentration and PTH levels and the presence of hyperparathyroidism cross-sectionally.

RESULTS

The geometric means and 95% confidence interval (95% CI) concentrations of urinary perchlorate, nitrate, and thiocyanate were 3.38 (3.15-3.62), 40363 (37512-43431), and 1129 (1029-1239) ng/mL, respectively. After adjusting for confounding variables and sample weights, creatinine-corrected urinary perchlorate was negatively associated with serum PTH levels in women (P = 0.001), and creatinine-corrected urinary nitrate and thiocyanate were negatively associated with serum PTH levels in both sex groups (P = 0.001 and P<0.001 for men, P = 0.018 and P<0.001 for women, respectively). Similar results were obtained from sensitivity analyses performed for exposure variables unadjusted for creatinine with urinary creatinine added as a separate covariate. There was a negative relationship between hyperparathyroidism and urinary nitrate and thiocyanate [odds ratio (95% CI) = 0.77 (0.60-0.98) and 0.69 (0.61-0.79), respectively].

CONCLUSIONS

A higher urinary concentration of perchlorate, nitrate, and thiocyanate is associated with lower serum PTH levels. Future studies are needed to determine the pathophysiological background of the observation.

Cinacalcet upregulates calcium-sensing receptors of parathyroid glands in hemodialysis patients

BACKGROUND

Cinacalcet hydrochloride (cinacalcet), a calcimimetic, has been shown to upregulate calcium-sensing receptor (CaSR) expression in parathyroid glands of rats with chronic renal insufficiency. However, the effect of cinacalcet on the reduced CaSR expression in human parathyroid glands remains to be elucidated.

METHODS

Four normal parathyroid glands and 71 hyperplastic parathyroid glands from 18 hemodialysis patients with refractory secondary hyperparathyroidism (SHPT) treated with (n = 10; cinacalcet group) or without (n = 8; conventional group) cinacalcet were examined immunohistochemically with a specific antibody against CaSR. The expression level of CaSR was analyzed semiquantitatively.

RESULTS

Compared with normal glands, the immunohistochemical expression of CaSR was decreased significantly in both the cinacalcet and conventional groups. In the cinacalcet group, the expression of CaSR was increased significantly compared with that in the conventional group (1.83 ± 0.14 vs. 0.87 ± 0.15, p < 0.001), even though the proportion of patients using vitamin D sterols and the mean administered dose of calcitriol equivalents were not significantly different between the two groups. The expression of CaSR was significantly decreased in the larger glands (>500 mg) compared with that in the smaller glands (<500 mg) in both groups; furthermore, it was markedly decreased in areas of nodular hyperplasia compared with diffuse hyperplasia in the cinacalcet group.

CONCLUSIONS

Our results indicate that cinacalcet upregulates the depressed expression of CaSR in hemodialysis patients with SHPT, and that insufficient expression of CaSR, especially in larger glands with advanced nodular hyperplasia, underlies the pathogenesis of SHPT in patients who are resistant to cinacalcet.

Residual renal function is an independent determinant of serum FGF-23 levels in dialysis patients

BACKGROUND

Both poor residual renal function (RRF) and high fibroblast growth factor 23 (FGF-23) levels are associated with arterial stiffness, left ventricular hypertrophy and increased (cardiovascular) mortality. Whether FGF-23 and RRF are interrelated is unknown.

METHODS

We performed a prospective observational cohort study in 35 peritoneal dialysis (PD) patients with evaluation at 1, 6, 12 and 24 months after start of PD. In addition, the role of RRF was assessed in a cross-sectional observational cohort study including 68 prevalent haemodialysis patients.

RESULTS

RRF significantly declined over time in PD patients. This decline was parallelled by a significant increase of both serum phosphorus and FGF-23 levels. In the prevalent dialysis cohort, RRF was found to be inversely associated with serum FGF-23 levels, independent of dialysis vintage, dialytic creatinine clearance, estimates of dietary phosphate intake (i.e. normalized protein nitrogen appearance), active vitamin D therapy and serum phosphorus and calcium levels. RRF, serum phosphorus and calcium levels and active vitamin D therapy explain 69% of the variation in FGF-23. The 38 anuric patients had higher FGF-23 levels but similar serum phosphorus levels.

CONCLUSIONS

We demonstrate an important association between RRF and FGF-23, independent of classical determinants. This favours the hypothesis that the ailing kidney directly contributes to the raised FGF-23 levels. Whether FGF-23 is associated with poor outcomes independent of RRF, or vice versa, remains to be clarified.

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.

Does vitamin D receptor and calcium receptor activation therapy play a role in the histopathologic alterations of parathyroid glands in refractory uremic hyperparathyroidism?

BACKGROUND AND OBJECTIVES

Vitamin D receptor activation by vitamin D sterols and calcium-sensing receptor stimulation by cinacalcet are the most powerful treatments of secondary hyperparathyroidism. This study was aimed to assess a possible association between histopathologic changes of parathyroid tissue and treatment modality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Studies were performed on 82 parathyroids of 22 adult white hemodialysis patients undergoing first parathyroidectomy. The type of hyperplasia and the distribution of chief and oxyphil cells, expressed as oxyphil/chief cell ratio, were assessed. Three groups could be studied according to treatment modality: group A consisted of 6 patients who were treated with cinacalcet, intravenous calcitriol, and phosphate binders; group B consisted of 6 patients who were treated with intravenous calcitriol and phosphate binders, and group C consisted of 10 patients who were treated with phosphate binders alone.

RESULTS

Sixty-eight (82.9%) out of 82 glands removed showed nodular hyperplasia. It was more frequent in groups A and B than in group C. A stepwise forward logistic regression model showed that the probability of nodular hyperplasia was higher in patients who were on calcitriol and/or cinacalcet therapy, in female gender and in patients with a higher body mass index. Oxyphil/chief cell ratio also was significantly different among the three groups. Cinacalcet treatment was the only predictor of this ratio.

CONCLUSIONS

An association was found between calcitriol and/or cinacalcet therapy and a high prevalence of nodular hyperplasia, and between cinacalcet therapy and high oxyphil/chief cell ratio. The meaning of the observed associations remains uncertain.

The effect of binge fetal alcohol exposure on the number of vasoactive intestinal peptide-producing neurons in fetal sheep brain

Previously we demonstrated that fetal alcohol exposure attenuates hypoxic cerebral vasodilation in fetal and neonatal sheep. One mechanism may be altered expression of brain vasoactive substances. We hypothesized that early fetal alcohol exposure alters the number of fetal neurons expressing vasoactive intestinal peptide (VIP), a potent cerebral vasodilator. Thirteen pregnant ewes received daily i.v. infusions of alcohol (1.5 g/kg) or saline on days 30-54 of gestation (term = 145 days). Fourteen fetal brains (6 alcohol-exposed, 8 saline control) were obtained on gestational day 126. Using unbiased stereology, we counted immunohistochemically-labeled VIP neurons in one half of each forebrain with an optical fractionator. The total NeuN-labeled neurons were similarly counted. Alcohol-exposed fetal sheep brains had fewer VIP-immunopositive neurons per hemisphere, 14.6 x 10(6), compared to saline controls, 19.8 x 10(6). The total neuron number was not different, 1.19 x 10(9) versus 1.23 x 10(9) respectively, indicating a selective decrease in VIP neurons as a result of alcohol exposure. In sheep, alcohol exposure early in gestation is associated with fewer VIP-producing neurons later in gestation compared to saline controls; therefore, alcohol-related changes in the number of VIP-expressing neurons may be responsible in part for the attenuated hypoxic cerebral vasodilation described in fetal and neonatal sheep exposed to alcohol earlier in gestation.

Sestamibi Scintigraphy, Topography, and Histopathology of Parathyroid Glands in Secondary Hyperparathyroidism

BACKGROUND

Several imaging techniques presently are available to assess the location of hyperplastic parathyroid glands. The purpose of the present study is to assess the place of dual-phase technetium Tc 99m-sestamibi (MIBI) scintigraphy in the preoperative localization of hyperplastic parathyroid glands in patients with severe secondary hyperparathyroidism (SHPT).

METHODS

We studied 35 consecutive adult white hemodialysis patients undergoing a first parathyroidectomy after performing MIBI scintigraphy. Hyperplasia of the parathyroid glands was classified as diffuse (DH) or nodular (NH). Statistical analysis was conducted by comparing patients with MIBI-negative (no focal area of increased uptake) with MIBI-positive (> or = 1 focal area of increased uptake) results and stratifying parathyroid glands according to location (superior and inferior).

RESULTS

MIBI scintigraphy showed focal areas of increased uptake in at least 1 gland in 25 patients (71.4%). Total number of focal areas of increased uptake was 42 of 121 glands removed (sensitivity, 34.7%; specificity, 100%). One hundred one glands showed NH and 20 glands showed DH. The 25 patients with MIBI-positive results had 85 pathological glands removed, and the 10 patients with MIBI-negative results had 36 pathological glands removed: in the former, most glands showed NH (77 of 85 glands; 90.6%), and in the latter, 24 of 36 glands showed NH (66.7%; P = 0.004 at chi-square test). The sensitivity of MIBI scintigraphy for distinguishing specific subtypes of hyperplasia was 37.6% (38 of 101 glands) for NH and 20.0% (4 of 20 glands) for DH (P = 0.0005). The following values were significantly greater in inferior compared with superior glands: (1) estimated weight (2.1 +/- 0.8 versus 1.6 +/- 1.2 g; P = 0.04), (2) percentage of MIBI positivity (34 of 42 inferior glands [80.9%] versus 8 of 42 superior glands [19.1%]; P = 0.0001), and (3) percentage of localization permitted by MIBI scintigraphy (34 of 63 inferior glands [54.0%] versus 8 of 58 superior glands [13.8%]; P = 0.0001). Thus, NH, although equally distributed between inferior (53 of 63 glands) and superior (48 of 58 glands) glands, showed a percentage of MIBI positivity significantly greater in inferior (34 of 53 glands [64.1%]) compared with superior glands (8 of 48 glands [16.7%]; P = 0.0001).

CONCLUSION

MIBI scintigraphy did not show high sensitivity in identifying hyperplastic glands, although it was able to identify those with NH better than those with DH. Thus, MIBI scintigraphy has limited value preoperatively for patients with SHPT. Estimated weight, percentage of MIBI positivity, and percentage of localization permitted by MIBI scintigraphy were significantly greater in inferior glands.