The Epidemiology of Hypoparathyroidism in Italy: An 8-Year Register-Based Study

Quality of life in patients with hypoparathyroidism receiving standard treatment: an updated systematic review

PURPOSE

Hypoparathyroidism is defined by hypocalcemia with inappropriately normal or low parathyroid hormone levels. The current standard treatment consists of lifelong calcium and/ or vitamin D supplementation. Even while on stable treatment regimens, hypoparathyroid patients might still suffer from symptoms that can negatively impact their quality of life.

METHODS

A systematic literature review to identify the current knowledge regarding quality of life in patients with hypoparathyroidism receiving standard treatment was performed on November 1st, 2023. PubMed as well as Web of Science were searched. The systematic review is registered in PROSPERO (#CRD42023470924).

RESULTS

After removal of duplicates, 398 studies remained for title and abstract screening, after which 30 were included for full-text screening. After exclusion of seven studies with five studies lacking a control population, one using a non-validated questionnaire, and one being a subsample of the larger included study, 23 studies were included in this systematic review. The majority of the included studies used a guideline-conform definition of hypoparathyroidism, and the SF-36 was the most often applied tool. Almost all studies (87%) reported statistically significantly lower scores in at least one quality of life domain compared to a norm population or controls.

CONCLUSION

Patients with hypoparathyroidism receiving standard treatment report impairments in quality of life. The reasons for these impairments are probably multifaceted, making regular monitoring and the inclusion of various professionals necessary.

Presentation of hypoparathyroidism in Italy: a nationwide register-based study

PURPOSE

We sought to assess the clinical presentation of hypoparathyroidism (HypoPT) in Italy.

METHODS

We performed a nationwide study retrieving data from the hospital discharge ICD-9 codes database of the Italian Health Ministry, from 2007 through 2017. The codes corresponding to diagnosis of cardiovascular disease, cancer, infection, renal failure, psychiatric disease, upper airway tract infection and pneumonia, seizures, nephrolithiasis, cognitive impairment, cerebral calcifications, skin disorders, fracture, and cataract were retrieved when associated with the diagnosis of HypoPT (252.1). We excluded codes corresponding to diagnoses of cancer of the neck region. In-hospital mortality rate was calculated. We retrieved the same data from an age- and sex-matched non-HypoPT control population.

RESULTS

Fourteen thousand five hundred seventy-nine hospitalizations for HypoPT and controls were analyzed. Hospitalization for cardiovascular disease, cancer, infection, renal failure, seizures, nephrolithiasis, cerebral calcifications (p < 0.0001), and cognitive impairment (p < 0.05) were more common in HypoPT compared to controls. Mean age of HypoPT with cardiovascular disease, cancer, and renal failure was younger compared to controls (p < 0.0001). The OR of hospitalization for cardiovascular disease, cancer, renal failure, seizures (OR 2, 40, 48  and 1.6, respectively), and nephrolithiasis (OR 1.6) were significant in HypoPT compared to non-HypoPT. The OR of hospitalization for infection and cognitive impairment were significant only in HypoPT women (OR 1.3 and 2.3, respectively). In-hospital mortality rate was lower in HypoPT vs controls (0.5% and 3.7%; p < 0.0001).

CONCLUSION

Hospitalizations for cardiovascular disease, cancer, and renal failure are more prevalent and occur at a younger age in HypoPT vs non-HypoPT. Hospitalizations for seizures and nephrolithiasis are frequent in HypoPT; those for infection and cognitive impairment are more common in HypoPT women.

Microencapsulation of parathyroid cells via electric field and non-surgical transplantation approach

PURPOSE

Hypoparathyroidism is a rare disease with low PTH, mostly seen as a consequence of neck surgery. Current management is the prescription of calcium and vitamin D, but the definitive treatment is parathyroid allotransplantation, which frequently triggers an immune response, thus cannot achieve the expected success. To overcome this problem, encapsulation of allogeneic cells is the most promising method. By optimizing the standard alginate cell encapsulation technique with parathyroid cells under high-voltage application, the authors reduced the size of parathyroid-encapsulated beads and evaluated these samples in vitro and in vivo.

METHODS

Parathyroid cells were isolated, and standard-sized alginate macrobeads were prepared without any electrical field application, while microbeads in smaller sizes (< 500 µm), by the application of 13 kV. Bead morphologies, cell viability, and PTH secretion were evaluated in vitro for four weeks. For the in vivo part, beads were transplanted into Sprague-Dawley rats, and after retrieval, immunohistochemistry and PTH release were evaluated in addition to the assessment of cytokine/chemokine levels.

RESULTS

The viability of parathyroid cells in micro- and macrobeads did not differ significantly. However, the amount of in vitro PTH secretion from microencapsulated cells was significantly lower than that from macroencapsulated cells, although it increased throughout the incubation period. Immunohistochemistry of PTH staining in both of the encapsulated cells identified as positive after retrieval.

CONCLUSION

Contrary to the literature, a minimal in vivo immune response was developed for alginate-encapsulated parathyroid cells, regardless of bead size. Our findings suggest that injectable, micro-sized beads obtained using high-voltage may be a promising method for a non-surgical transplantation approach.

Hypoparathyroidism - management, information needs, and impact on daily living from the patients' perspective: results from a population-based survey

PURPOSE

Hypoparathyriodism (hypoPT) is a rare endocrine disorder. It is not known how hypoPT is managed in Germany or whether patients have unmet information needs or impairments in their daily living.

METHODS

HypoPT patients at a minimum of 6 months' post-diagnosis were invited to participate in an online survey through their treating physician or through patient organizations. An extensive questionnaire, which was developed and pilot-tested with hypoPT patients, was administered.

RESULTS

A total of 264 patients with a mean age of 54.5 years (SD: 13.3), 85.2% female and 92% with postsurgical hypoPT, participated in the study. In total, 74% of the patients reported regular monitoring of serum calcium at least every 6 months, with lower control frequencies for phosphate (47%), magnesium (36%), creatinine (54%), and parathyroid hormone (50%), and 24-h urine calcium excretion (36%) on a yearly basis. Information on symptoms of hypo- and hypercalcemia was available in 72 and 45% of the patients. Information needs were related to the disease and its treatment as well as to nutrition, physical activities/sports, and support opportunities. Statistically significant differences for all information needs in association with symptom burden were observed. Hospitalization for hypocalcemia was reported by 32%, nutritional impairments (38%) or impact on work ability (52%) was available among patients with hypoPT.

CONCLUSION

HypoPT patients experience impairments in daily living and report unmet information needs. Patient and physician education regarding hypoPT is one of the key concepts for improving the management of patients with hypoPT.

Recent Trends in Hypoparathyroidism-Related Inpatient and Emergency Department Admissions and Costs in the United States

Hypoparathyroidism (HypoPT) is a rare disease associated with high morbidity. Its economic impact is not well understood. This retrospective, cross-sectional study used data from the United States-based National Inpatient Sample and the Nationwide Emergency Department Sample from 2010 to 2018 to quantify overall trends in number, cost, charges, and length of stay (LOS) for inpatient hospitalizations and number and charges for emergency department (ED) visits for HypoPT-related and for non-HypoPT-related causes. Additionally, the study estimated the marginal effect of HypoPT on total inpatient hospitalization costs and LOS as well as ED visit charges. Over the observed period, a mean of 56.8-66.6 HypoPT-related hospitalizations and 14.6-19.5 HypoPT-related ED visits were recorded per 100 000 visits per year. Over this period, the rate of HypoPT-related inpatient hospitalizations and ED visits increased by 13.5% and 33.6%, respectively. The mean LOS for HypoPT-related hospitalizations was consistently higher than for non-HypoPT-related causes. Total annual HypoPT-related inpatient hospitalization costs increased by 33.6%, and ED visit charges increased by 96.3%. During the same period, the annual costs for non-HypoPT-related hospitalizations and charges for ED visits increased by 5.2% and 80.3%, respectively. In all years, HypoPT-related hospital encounters resulted in higher charges and costs per individual visit than non-HypoPT-related encounters. The marginal effect of HypoPT on inpatient hospitalization costs and LOS, and on ED charges, increased over the period of observation. This study demonstrated that HypoPT was associated with substantial and increasing healthcare utilization in the United States between 2010 and 2018.

Epidemiology and Financial Burden of Adult Chronic Hypoparathyroidism

Chronic hypoparathyroidism is characterized by low serum calcium, increased serum phosphorus, and inappropriately low or decreased serum parathyroid hormone. This rare disorder is associated with a variety of complications. The prevalence, incidence, mortality, financial burden, and epidemiology of complications of this disorder are not well understood. This narrative review summarizes current information on the epidemiology and complications of chronic hypoparathyroidism. The reported prevalence of chronic hypoparathyroidism ranges from 6.4-37/100,000, and the incidence is reported to be 0.8-2.3/100,000/year. Mortality is not increased in studies from Denmark or South Korea but was increased in studies from Scotland and Sweden. The financial burden of this disorder is substantial because of increased health care resource utilization in two studies but not well quantitated. Recognized complications include hypercalciuria, nephrocalcinosis, kidney stones, and chronic kidney disease; low bone turnover and possibly upper extremity fractures; cardiac and vascular calcifications; basal ganglia calcifications, cataracts, infections, neuropsychiatric complications, and difficulties with pregnancy. This review concludes that chronic hypoparathyroidism is a rare disorder associated with significant morbidity that may not increase overall mortality but is associated with a substantial financial burden. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Kidney Complications and Hospitalization in Patients With Chronic Hypoparathyroidism: A Cohort Study in Sweden

CONTEXT

Kidney complications may be considerably higher in patients with chronic hypoparathyroidism (hypoPT) treated with activated vitamin D and calcium supplementation.

OBJECTIVE

We aimed to investigate the risk of chronic kidney disease (CKD), urolithiasis, and hospitalization in patients with chronic hypoPT.

METHODS

In this population-based cohort study in Sweden, national registries (Swedish National Patient Register, Swedish Prescribed Drug Register, and Total Population Register, 1997-2018) were used to identify patients with chronic hypoPT and controls matched by sex, age, and county of residence. We determined time to CKD and urolithiasis diagnosis, and incidence rates of hospitalization.

RESULTS

A total of 1562 patients with chronic hypoPT without preexisting CKD and 15 620 controls were included. The risk of developing CKD was higher in patients with chronic hypoPT compared with controls (hazard ratio [HR] 4.45; 95% CI, 3.66-5.41). In people without prior urolithiasis (n = 1810 chronic hypoPT and n = 18 100 controls), the risk of developing urolithiasis was higher in patients with chronic hypoPT (HR 3.55; 95% CI, 2.84-4.44) compared with controls. Patients with chronic hypoPT had higher incidence rates for all-cause hospitalization (49.59; 95% CI, 48.50-50.70, per 100 person-years vs 28.43; 95% CI, 28.15-28.71, respectively) and for CKD (3.46; 95% CI, 3.18-3.76, per 100 person-years vs 0.72; 95% CI, 0.68-0.77, respectively), compared with controls. Men with hypoPT appear to have a higher risk of CKD than women.

CONCLUSION

Patients with chronic hypoPT had an increased risk of CKD, urolithiasis, and hospitalization compared with controls.

Effect of postsurgical chronic hypoparathyroidism on morbidity and mortality: a systematic review and meta-analysis

Background

Hypoparathyroidism (HypoPT) is a common sequela of anterior neck surgeries. While the acute risks of HypoPT are well known, emerging evidence is beginning to define the risks chronic HypoPT poses to patients. This meta-analysis aims to evaluate that risk and give more insight into its consequences.

Methods

A systematic review and meta-analysis were performed, searching EMBASE, Web of Science, and Scopus for studies published up to July 1, 2020 and reported following PRISMA guidelines. Pooled analysis was estimated using the Mantel-Haenszel method and a random-effects model. A sub-analysis of the pooled data for each morbidity was performed and demonstrated in forest plots.

Results

Patients with postsurgical chronic HypoPT had a high risk of cardiac morbidities [odds ratio (OR) =1.43; 95% confidence interval (95% CI): 1.21 to 1.70; P<0.001] in the absence of elevated risk of cardiac arrhythmias (OR =1.35, 95% CI: 0.96 to 1.79, P=0.08). Analysis also showed higher odds of developing renal disease (OR =4.85, 95% CI: 3.54 to 6.67, P<0.001), renal stones (OR =3.86, 95% CI: 1.81 to 8.23, P<0.001), seizures (OR =2.41, 95% CI: 1.66 to 3.5, P<0.001), mental health problems (OR =1.46, 95% CI: 1.21 to 1.77, P<0.001), and infections (OR =1.51, 95% CI: 1.28 to 1.78, P<0.001). Conversely, HypoPT has no effect on mortality risk (OR =1.19, 95% CI: 0.96 to 1.49, P=0.12).

Conclusions

Postsurgical HypoPT patients are vulnerable to a variety of medical and psychiatric diseases. This meta-analysis should guide surgeons in preoperative counseling and postoperative care for patients undergoing anterior neck surgeries.

Burden of illness in patients with chronic hypoparathyroidism not adequately controlled with conventional therapy: a Belgium and the Netherlands survey

PURPOSE

To determine the burden of illness in patients with not adequately controlled chronic hypoparathyroidism receiving conventional therapy in Belgium and the Netherlands.

METHODS

Data were generated from a cross-sectional, two-part online survey where endocrinologists from both countries and nephrologists from Belgium were invited by phone to participate. Part 1 included collecting data on general management of patients with hypoparathyroidism. In Part 2, physicians were requested to provide data on one or two current cases of patients with chronic hypoparathyroidism not adequately controlled on conventional therapy. Data collected included aetiology of hypoparathyroidism, clinical manifestations, comorbidities, results of laboratory and other investigations used for diagnosis and screening for complications, therapy received, and physician's perception of impaired quality of life (QoL).

RESULTS

Thirty-six endocrinologists and 29 nephrologists from Belgium and 28 endocrinologists from the Netherlands participated in the survey. Data included clinical symptoms, biochemical parameters, and QoL for 97 current patients with not adequately controlled chronic hypoparathyroidism on conventional therapy. Median duration of not adequately controlled hypoparathyroidism was 2.2 years, range 0.17-20.0. Most patients had neuromuscular (85%) and/or neurological (67%) symptoms, 71% had abnormal biochemical parameters, 10% were overweight, and physicians perceived that 71% had impaired QoL. Most frequently reported comorbidities included hypertension (25%), renal comorbidity (20%), diabetes mellitus (12%), and dyslipidaemia (11%).

CONCLUSION

Patients with chronic hypoparathyroidism not adequately controlled on conventional therapy experience a substantial burden of illness, mainly due to persistence of symptoms and presence of multiple comorbidities.

The association between hypoparathyroidism and cognitive impairment: a systematic review

CONTEXT AND PURPOSE

Hypocalcemia and low parathyroid hormone levels have been commonly suggested as factors able to induce central nervous system disturbances. However, evidences on the occurrence of cognitive impairment are limited or underestimated. The aim of this review is, therefore, to systematically summarize the available evidence concerning the occurrence of cognitive impairment among subjects suffering from idiopathic or secondary hypoparathyroidism.

METHODS

A systematic selection of the available literature was performed by searching the online databases PubMed, Scopus and Web of Knowledge.

RESULTS

The present systematic review included sixteen case report articles and one cross-sectional controlled study. Case reports were the most representative literature sources and involved ten women and seven men. The presence of cognitive impairment was mostly discussed in association with idiopathic hypoparathyroidism (HPT); five articles described the occurrence of cognitive impairment following postsurgical HPT. The case-controlled study reported a significant presence of peculiar cognitive deficits (e.g. reduced inhibitory control, impairment in visuo-spatial functioning among, and psychomotor retardation) among HPT subjects compared to healthy controls, with serum total calcium and its product with phosphorus as independent predictors of neuropsychological dysfunctions.

CONCLUSION

Even though mostly based on single case reports, the presence of neuropsychological dysfunctions in the context of HPT appears to be a consistent core finding.

Vertebral Fracture Assessment in Postmenopausal Women With Postsurgical Hypoparathyroidism

CONTEXT

Hypoparathyroidism is a rare endocrine disorder whose skeletal features include suppression of bone turnover and greater volume and width of the trabecular compartment. Few and inconsistent data are available on the prevalence of vertebral fractures (VF).

OBJECTIVE

To evaluate the prevalence of VF assessed by vertebral fracture assessment (VFA) in postmenopausal women with chronic postsurgical hypoparathyroidism.

DESIGN

Cross-sectional study.

SETTING

Ambulatory referral center.

PATIENTS OR OTHER PARTICIPANTS

Fifty postmenopausal women (mean age 65.4 ± 9 years) with chronic postsurgical hypoparathyroidism and 40 age-matched healthy postmenopausal women (mean age 64.2 ± 8.6).

MAIN OUTCOME MEASURES

Lumbar spine, femoral neck, and total hip bone mineral density were measured by dual X-ray absorptiometry (Hologic Inc., USA) in all subjects. Site-matched spine trabecular bone score was calculated by TBS iNsight (Medimaps, Switzerland). Assessment of VF was made by VFA (iDXA, Lunar GE, USA) using the semiquantitative method and the algorithm-based qualitative assessment.

RESULTS

All-site BMD values were higher in the hypoparathyroid vs the control group. By VFA, we observed a 16% prevalence of VF in hypoparathyroid women vs 7.5% in control subjects. Among those with hypoparathyroidism who fractured, 5 (62.5%) had grade 1 wedge, 2 (25%) had grade 2 wedge, and 1 (12.5%) had grade 2 wedge and grade 2 biconcave VF. In the hypoparathyroid group, 57% with VFs and 32% without VFs had symptoms of hypoparathyroidism.

CONCLUSION

We demonstrate for the first time that in postmenopausal women with chronic postsurgical hypoparathyroidism, VFs are demonstrable by VFA despite normal BMD.

Chronic hypoparathyroidism and treatment with teriparatide

PURPOSE

Chronic hypoparathyroidism is usually treated with calcium and active vitamin D metabolites or analogs, despite the fact that their chronic use can lead to long-term complications. The use of hormone replacement therapy with PTH peptides [teriparatide and rhPTH (1-84)] has therefore been proposed. The main purpose of this study was to investigate the efficacy of teriparatide dose at 20 µg once or twice daily, in order to maintain normocalcemia reducing standard treatment, in adult patients with chronic hypoparathyroidism not well controlled with conventional treatment.

METHODS

The study was a Phase III, open-label, non-comparative, clinical investigation (study period: 3 months), at a tertiary care clinical research center. Thirty patients with chronic hypoparathyroidism were screened, and 12 started teriparatide. After the optimization phase (0-4 weeks), calcium and calcitriol supplements were progressively reduced, while teriparatide 20 µg once daily was administered (5-7 weeks), and then could be titrated up to 20 µg twice daily (7-17 weeks). The main outcome measures included serum and urinary biochemical exams and Rand 36-Item Short Form Health Survey.

RESULTS

This study showed that teriparatide 20 µg once daily was insufficient to discontinue calcium and calcitriol supplements to maintain normal serum calcium concentrations. Conversely, for more than half of patients treated with teriparatide 20 µg twice daily, calcium and calcitriol administration was avoidable, but in some cases at the expense of serum calcium and phosphate oscillations.

CONCLUSIONS

Since intervention trials evaluating the efficacy and safety of teriparatide in hypoparathyroid patients are not yet available, the routine use of this molecule poses some doubts.

Diagnosis and management of hypocalcemia

The aim of this clinical narrative review is to summarize and critically appraise the literature on the differential diagnosis of hypocalcemia and to provide its correct management. Calcium is essential for muscle contraction and neurotransmitter release, but clinical manifestations of hypocalcaemia (serum calcium level <8 mg/dl; 2.12 mmol/L) may involve almost any organ and system and may range from asymptomatic to life-threating conditions. Disorders causing hypocalcemia can be divided into parathyroid hormone (PTH) and non-PTH mediated. The most frequent cause of hypocalcemia is postsurgical hypoparathyroidism, while a more comprehensive search for other causes is needed for appropriate treatment in the non PTH-mediated forms. Intravenous calcium infusion is essential to raise calcium levels and resolve or minimize symptoms in the setting of acute hypocalcemia. Oral calcium and/or vitamin D supplementation is the most frequently used as treatment of chronic hypocalcemia. In hypoparathyroidism, providing the missing hormone with the use of the recombinant human (rh) PTH(1-84) has been recently approved both by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA). This new therapy has the advantage of being effective for correcting serum calcium levels and significantly reducing the daily requirements of calcium and active vitamin D supplements. However, due to the high cost, a strict selection of candidates to this therapy is necessary. More challenging is the long-term hypocalcemia treatment, due to its associated complications. The development of long-acting recombinant human PTH will probably modify the management of chronic hypoparathyroidism in the future.

A registry for patients with chronic hypoparathyroidism in Russian adults

Hypoparathyroidism and pseudohypoparathyroidism are rare endocrine disorders, characterized by low serum calcium due to inappropriate parathyroid hormone (PTH) levels or resistance to its action. There is little epidemiological information regarding chronic hypoparathyroidism in Russia. This study aims to build a registry database of Russian patients with chronic hypoparathyroidism who were referred for hospital treatment in order to conduct initial analysis of clinical presentations and hospital management. The Italian registry model was taken to be able to integrate our data in the future. Two hundred patients with hypoparathyroidism (n = 194) and pseudohypoparathyroidism (n = 6) were enrolled over 2 years (2017-2019). The most frequent cause of hypoparathyroidism was neck surgery (82.5%, mostly females), followed by idiopathic hypoparathyroidism (10%), syndromic forms of genetic hypoparathyroidism (4.5%) and forms of defective PTH action (3%). Calcium supplements and alfacalcidol were prescribed in most cases. However, a minority of patients (n = 6) needed to receive teriparatide as the only way to maintain calcium levels and to prevent symptoms of hypocalcemia. Consequently, substitution treatment with parathyroid hormone should be available in certain cases of hypoparathyroidism. This database will be useful to estimate the potential requirement for recombinant PTH in Russia and standards for clinical and therapeutic approaches.

Hypoparathyroidism

BACKGROUND

Hypoparathyroidism is a rare endocrine disorder characterized by hypocalcemia and low or undetectable levels of parathyroid hormone.

METHODS

This review is an evidence-based summary of hypoparathyroidism in terms of relevant pathophysiological, clinical, and therapeutic concepts.

RESULTS

Many clinical manifestations of hypoparathyroidism are due to the lack of the physiological actions of parathyroid hormone on its 2 major target organs: the skeleton and the kidney. The skeleton is inactive, accruing bone without remodeling it. The kidneys lose the calcium-conserving actions of parathyroid hormone and, thus, excrete a greater fraction of calcium. Biochemical manifestations, besides hypocalcemia and low or undetectable levels of parathyroid hormone, include hyperphosphatemia and low levels of 1,25-dihydroxyvitamin D. Calcifications in the kidney, brain, and other soft tissues are common. Removal of, or damage to, the parathyroid glands at the time of anterior neck surgery is, by far, the most likely etiology. Autoimmune destruction of the parathyroid glands and other genetic causes represent most of the other etiologies. Conventional treatment with calcium and active vitamin D can maintain the serum calcium level but high doses may be required, adding to the risk of long-term soft tissue calcifications. The advent of replacement therapy with recombinant human PTH(1-84) represents a major step in the therapeutics of this disease.

CONCLUSIONS

Advances in our knowledge of hypoparathyroidism have led to greater understanding of the disease itself and our approach to it.

Characteristics of hypoparathyroidism in Colombia: data from a single center in the city of Medellín

OBJECTIVE

Hypoparathyroidism is a rare condition, whose most common etiology is complications of neck surgery. The aim of the study was to identify the clinical and biochemical profile of the patients with diagnosis of hypoparathyroidism, including the frequency of symptoms, clinical signs, long-term complications and disease control. Additionally, the study sought to know what the medication profile was, and the doses required by the patients.

SUBJECTS AND METHOD

A retrospective cohort study was conducted wherein all patients with ICD-10 codes associated with hypoparathyroidism between 2011 and 2018 at the Hospital Universitario San Vicente Fundación were included. We investigated the etiology of the disease; biochemical profile including lowest serum calcium, highest serum phosphorus, 25OHD levels, calciuria and calcium/phosphorus product; medication doses, disease control, and presence of complications, especially renal and neurologic complications were also evaluated.

RESULTS

The cohort included 108 patients (99 women/9 men) with a mean age of 51.6 ± 15.6 years. The main etiology was postoperative (93.5%), the dose of elemental calcium received was relatively low (mean 1,164 mg/day), and in only 9.2% of cases more than 2,500 mg/day of elemental calcium was necessary. We were able to evaluate the follow-up in 89 patients, and found that only 57.3% met the criteria for controlled disease.

CONCLUSION

The clinical profile of patients with hypoparathyroidism in our cohort is similar to that described in other international studies, with predominantly postoperative etiology. With standard therapy, only adequate control is achieved in a little more than half of patients. Arch Endocrinol Metab. 2020;64(3):282-9.

Update on hypoparathyroidism

PURPOSE OF REVIEW

Hypoparathyroidism is a rare endocrine disorder characterized by low or insufficient parathyroid hormone (PTH) concentrations leading to hypocalcemia, hyperphosphatemia, and markedly reduced bone turnover. Despite being a rare disease, hypoparathyroidism has a profound impact on affected patients.

RECENT FINDINGS

Recent epidemiologic surveys demonstrate a prevalence of between 5.3 and 40/100 000, confirming the orphan status of this disease. There is a female predominance, and anterior neck surgery is the most common etiology. Recent studies have better elucidated the chronic manifestations of the disease, impacting quality of life and multiple organ systems including the renal, cardiovascular, and skeletal systems. There are now data on longer term use of parathyroid hormone (PTH) and PTH analogs.

SUMMARY

This review focuses on recent contributions to the literature on the prevalence and epidemiology of the disease, risk of chronic manifestations, and treatment with PTH(1-34) and rhPTH(1-84). Further research is needed to determine the pathophysiology of complications in hypoparathyroidism and whether interventions can decrease future risk of these complications. In addition, further data are needed with regards to more physiologic dosing regimens and long-term treatment with PTH and PTH analogs.

[Hypoparathyroidism - un underestimated problem?]

BACKGROUND

Hypoparathyroidism is a rare and disabilitating disorder characterized by hypocalcemia and low parathyroid hormone levels. Most of the cases occur as a result of the removal of parathyroid glands or damage to the glands during neck surgery. More rare causes include nonsurgical causes such as autoimmune or genetic diseases.

METHOD

In this review, a panel of experts presents the current state of diagnosis and therapy of hypoparathyroidism and explains practical aspects of caring for the affected patients.

RESULTS

Common signs and symptoms are abnormal sensations and increased excitability in the lower limbs, paresthesia of perioral areas and nocturnal leg cramps. Renal complications frequently occur, but also basal ganglia calcification. Treatment consists of administration of vitamin D analogs in combination with 0.5-1.0 g calcium daily. An adjunctive treatment with the in April 2017 approved recombinant human parathyroid hormone (1-84) is an option for patients whose hypoparathyroidism is difficult to control by conventional treatment alone. Initially and after dose changes follow-up controls should be performed at least every 2 weeks, in well-controlled patients or in the case of chronic progression every 3-6 months.

Concordance Between ICD-10 Codes and Clinical Diagnosis of Hypoparathyroidism in Sweden

Introduction

Chronic hypoparathyroidism is a rare disorder. The disease is characterized by low serum calcium, high serum phosphate, and deficient production of parathyroid hormone. The most common etiology is unintentional damage and intentional removal to the parathyroid glands during anterior neck surgery. Other causes include genetic disorders and autoimmune diseases. Knowledge about the epidemiology of chronic hypoparathyroidism is sparse and the prevalence in Sweden is unknown. It is of importance to know the validity of the registers used to study the epidemiology of hypoparathyroidism in Sweden.

The purpose of this study was to validate the International Classification of Diseases - 10th revision (ICD-10) diagnosis of hypoparathyroidism in the Swedish National Patient Register.

Methods

We included patients with the ICD-10 diagnosis of hypoparathyroidism that were found in the Swedish National Patient Register during 2004 to 2016. Through the unique national registration number assigned to all Swedish inhabitants, we could link this information to the Swedish Prescribed Drug Register. We included patients with an ICD-10 diagnosis for hypoparathyroidism and on concurrent conventional treatment for the disease. The validation of the diagnosis was assessed through review of medical records of 120 patients.

Results

A total of 958 patients, 70% women (n=671) and 30% men (n=287) met the inclusion criteria. In total, 120 randomly chosen medical records were reviewed and 109 cases were confirmed. This corresponds to an overall positive predictive value of 91%.

Conclusion

The validity of the ICD-10 diagnosis of hypoparathyroidism in the Swedish National Patient Register is high and the register is a reliable source for further research. There is a risk of miscoding when assigning an ICD-code to the medical records. We urge clinicians to be aware of this risk, especially the risk of mix-ups with the more common diagnosis of hyperparathyroidism.

Epidemiology and Complications of Hypoparathyroidism

Until recently, very few studies have described the epidemiology of this rare disorder. Several large population-based studies have recently been published describing the prevalence and incidence of hypoparathyroidism in various countries. Some of these studies have described the epidemiology of both postsurgical and nonsurgical hypoparathyroidism. In addition, a number of studies have now been published describing the prevalence of complications of this disorder. This article summarizes the published medical literature regarding the prevalence and incidence of this disorder, and the risk of known complications of hypoparathyroidism.

Causes and pathophysiology of hypoparathyroidism

Hypoparathyroidism, a disorder characterized by hypocalcemia ensuing from inadequate parathyroid hormone secretion, is a rather rare disorder caused by multiple etiologies. When not caused by inadvertent damage or removal of the parathyroids during neck surgery, it is usually genetically determined. Epidemiological figures of this disease are still scarce and mainly limited to countries where non-anonymous databases are available and to surgical case series. Both the surgical and non-surgical forms pose diagnostic challenges. For surgical hypoparathyroidism, transient forms have to be ruled out even in the long term, in order to avoid unnecessary chronic replacement therapy with calcium and calcitriol. Regarding non-surgical hypoparathyroidism, once referred to as idiopathic, a systematic clinically and genetically-driven approach to define the precise diagnosis have to be pursued. In the case of syndromic hypoparathyroidism, patients have to be screened for associated abnormalities. Autoimmune, non-genetic hypoparathyroidism is still a diagnosis of exclusion, since no specific autoantibodies are specific for this condition.

Prevalence of Chronic Hypoparathyroidism in a Mediterranean Region as Estimated by the Analysis of Anonymous Healthcare Database

Epidemiological data on prevalence and incidence of chronic hypoparathyroidism are still scarce. This study aimed to establish prevalence of chronic hypoparathyroidism and incidence of surgical hypoparathyroidism using the analysis of electronic anonymous public health care database. Data referred to a 5-year period (2009-2013, Region of Tuscany, Italy, as a sample representative of the whole Mediterranean/European population, estimated mean population: 3,750,000 inhabitants) were retrieved by the analysis of pharmaceutical distribution dataset, containing data related to drugs reimbursed by public health system, hospital discharge and procedures codes, and ICD9 exemption codes for chronic diseases. The application of a specific algorithm was applied to indirectly identify people with chronic hypoparathyroidism as assuming chronic therapy with active vitamin D metabolites (AVDM). The number of people taking AVDM for a period equal to or longer than 6 months till the end of the study period, with ICD9 exemption code for hypoparathyroidism, and with a disease-related discharge code were identified. Within this restricted group, patients with chronic kidney disease and osteoporosis were excluded. The indirect estimate of chronic hypoparathyroidism in a European Mediterranean subpopulation by means of the analysis of chronic therapy with AVDM was 27/100,000 inhabitants (female:male ratio = 2.2:1), with a mean age of 63.5 ± 16.7 years. The risk of developing hypoparathyroidism after neck surgery was 1.5%. While the epidemiological approaches based on disease code and hospital discharge code greatly underestimates the prevalence of hypoparathyroidism, the indirect estimate of this disease through the analysis of prescriptions of AVDM in a European region is in line with the results of studies performed in other regions of the world.

HypoparaNet: A Database of Chronic Hypoparathyroidism Based on Expert Medical-Surgical Centers in Italy

Hypoparathyroidism is a rare disease characterized by low serum calcium levels and absent or deficient parathyroid hormone level. Regarding the epidemiology of chronic hypoparathyroidism, there are limited data in Italy and worldwide. Therefore, the purpose of this study was to build a unique database of patients with chronic hypoparathyroidism, derived from the databases of 16 referral centers for endocrinological diseases, affiliated with the Italian Society of Endocrinology, and four centers for endocrine surgery with expertise in hypoparathyroidism, to conduct an epidemiological analysis of chronic hypoparathyroidism in Italy. The study was approved by the Institutional Review Board. A total of 537 patients with chronic hypoparathyroidism were identified. The leading etiology was represented by postsurgical hypoparathyroidism (67.6%), followed by idiopathic hypoparathyroidism (14.6%), syndromic forms of genetic hypoparathyroidism (11%), forms of defective PTH action (5.2%), non-syndromic forms of genetic hypoparathyroidism (0.9%), and, finally, other forms of acquired hypoparathyroidism, due to infiltrative diseases, copper or iron overload, or ionizing radiation exposure (0.7%). This study represents one of the first large-scale epidemiological assessments of chronic hypoparathyroidism based on data collected at medical and/or surgical centers with expertise in hypoparathyroidism in Italy. Although the study presents some limitations, it introduces the possibility of a large-scale national survey, with the final aim of defining not only the prevalence of chronic hypoparathyroidism in Italy, but also standards for clinical and therapeutic approaches.

A Population-Based Study of the Epidemiology of Chronic Hypoparathyroidism

There are very few reports on the epidemiology of chronic hypoparathyroidism. A population-based study was undertaken to describe the prevalence and incidence of hypoparathyroidism in Tayside, Scotland. Data on biochemistry, hospital admissions, prescribing, and death records in Tayside, Scotland, from 1988 to 2015 were linked electronically. Patients with at least three serum albumin-corrected calcium concentrations below the reference range that were taken in an outpatient setting were included in the study. Patients with severe chronic kidney disease before low calcium were excluded from the study. Patients with hypocalcemia were included if they had either previous neck surgery/irradiation, a low serum parathyroid hormone (PTH), or were treated with vitamin D. Patients were identified as having either a postsurgical or a nonsurgical cause or had secondary hypoparathyroidism, eg, hypomagnesemia. Overall, 18,955 patients were identified with hypocalcemia. Of these, 222 patients had primary hypoparathyroidism, 116 with postsurgical and 106 with nonsurgical chronic hypoparathyroidism. In 2015, the prevalence of primary hypoparathyroidism was 40 per 100,000, with a rate of 23 and 17 per 100,000, respectively, for postsurgical and nonsurgical. Eighty percent of the former and 64% of the latter were female. The mean serum calcium at diagnosis was 1.82 mmol/L (SD ± 0.24) and the annual incidence varied from 1-4 per 100,000. Overall, 71% of patients were prescribed vitamin D and/or calcium, whereas activated vitamin D was used in 48% of postsurgical cases and 43% of nonsurgical cases. Thyroxine and/or hydrocortisone were prescribed in more than 90% of postsurgical and 64% of nonsurgical cases. In conclusion, the prevalence of nonsurgical chronic hypoparathyroidism was greater than previously reported using this population-based approach. Many had mild hypocalcemia and did not receive any treatment. © 2017 American Society for Bone and Mineral Research.

Hypoparathyroidism

Hypoparathyroidism is a disease characterized by inadequately low circulating concentrations of parathyroid hormone (PTH) resulting in low calcium levels and increased phosphate levels in the blood. Symptoms of the disease result from increased neuromuscular irritability caused by hypocalcaemia and include tingling, muscle cramps and seizures. The most common cause of the disease is inadvertent removal of, or injury to, the parathyroid glands during neck surgery, followed by genetic, idiopathic and autoimmune aetiologies. Conventional treatment includes activated vitamin D and/or calcium supplements, but this treatment does not fully replace the functions of PTH and can lead to short-term problems (such as hypocalcaemia, hypercalcaemia and increased urinary calcium excretion) and long-term complications (which include nephrocalcinosis, kidney stones and brain calcifications). PTH replacement has emerged as a new treatment option. Clinical trials using human PTH(1-34) and PTH(1-84) showed that this treatment was safe and effective in studies lasting up to 6 years. Recombinant human PTH(1-84) has been approved in the United States and Europe for the management of hypoparathyroidism; however, its effect on long-term complications is still being evaluated. Clinical practice guidelines, which describe the consensus of experts in the field, have been published and recognize the need for more research to optimize care. In this Primer, we summarize current knowledge of the prevalence, pathophysiology, clinical presentation and management of hypoparathyroidism.