Clinical outcomes after parathyroidectomy in a nationwide cohort of patients on hemodialysis.

BACKGROUND AND OBJECTIVES: Patients receiving dialysis undergo parathyroidectomy to improve laboratory parameters in resistant hyperparathyroidism with the assumption that clinical outcomes will also improve. However, no randomized clinical trial data demonstrate the benefits of parathyroidectomy. This study aimed to evaluate clinical outcomes up to 1 year after parathyroidectomy in a nationwide sample of patients receiving hemodialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Using data from the US Renal Data System, this study identified prevalent hemodialysis patients aged ≥18 years with Medicare as primary payers who underwent parathyroidectomy from 2007 to 2009. Baseline characteristics and comorbid conditions were assessed in the year preceding parathyroidectomy; clinical events were identified in the year preceding and the year after parathyroidectomy. After parathyroidectomy, patients were censored at death, loss of Medicare coverage, kidney transplant, change in dialysis modality, or 365 days. This study estimated cause-specific event rates for both periods and rate ratios comparing event rates in the postparathyroidectomy versus preparathyroidectomy periods. RESULTS: Of 4435 patients who underwent parathyroidectomy, 2.0% died during the parathyroidectomy hospitalization and the 30 days after discharge. During the 30 days after discharge, 23.8% of patients were rehospitalized; 29.3% of these patients required intensive care. In the year after parathyroidectomy, hospitalizations were higher by 39%, hospital days by 58%, intensive care unit admissions by 69%, and emergency room/observation visits requiring hypocalcemia treatment by 20-fold compared with the preceding year. Cause-specific hospitalizations were higher for acute myocardial infarction (rate ratio, 1.98; 95% confidence interval, 1.60 to 2.46) and dysrhythmia (rate ratio 1.4; 95% confidence interval1.16 to 1.78); fracture rates did not differ (rate ratio 0.82; 95% confidence interval 0.6 to 1.1). CONCLUSIONS: Parathyroidectomy is associated with significant morbidity in the 30 days after hospital discharge and in the year after the procedure. Awareness of clinical events will assist in developing evidence-based risk/benefit determinations for the indication for parathyroidectomy.

[Evaluation assessment of the cut-off point of vitamin D in the population older than 64 years old]. / Valoración del umbral óptimo de vitamina D en la población mayor de 64 años.

BACKGROUND AND OBJECTIVE: Serum 25(OH)D(3) is the best indicator of vitamin D status, although some controversy remains regarding "normal" and "abnormal" values. The objective was to identify the 25(OH)D(3) serum concentration threshold which allows to know the 25(OH)D(3) serum levels correlated to PTH(i) increase and to describe the prevalence of hypovitaminosis D. PATIENTS AND METHOD: Cross-sectional population study in subjects over 64 years of age residing in the basic healthcare areas in our hospital's area of reference. RESULTS: A total of 239 persons -mean age (standard deviation) 72 (5.4) years- were evaluated. Mean serum concentrations of 25(OH)D(3) and PTH(i) were 17 (7.5) ng/ml and 60.5 (26.1) pg/ml, respectively. 32% of the subjects showed an increase in the serum concentration of PTH(i) > 65 pg/ml. 96% of the cases with an increase in PTH(i) had serum concentrations of 25(OH)D(3) < or = 25.5 ng/ml. In 70% of the subjects, the serum concentration levels of 25(OH)D(3) ranged between 11 and 25 ng/ml and in 17% the levels of 25(OH)D(3) were lower than 10 ng/ml. CONCLUSIONS: The normal ranges for our population could correspond to levels of 25(OH)D3 > or = 25 ng/ml, with a 95% of sensibility to detect secondary hyperparathyroidism.

Yield of laboratory testing to identify secondary contributors to osteoporosis in otherwise healthy women.

Our purpose in this study was to determine the prevalence of undetected disorders of bone and mineral metabolism in women with osteoporosis and to identify the most useful and cost-efficient screening tests to detect these disorders. A cross-sectional study was conducted among 664 postmenopausal women with osteoporosis at the Osteoporosis and Metabolic Bone Disease Program at the Mount Sinai Hospital in New York between January 1992 and June 1996. Women without a history of diseases or medications known to adversely affect bone who completed extensive laboratory testing including complete blood count, chemistry profile, 24-h urinary calcium, 25(OH)vitamin D, and PTH were included. Among 173 women who met the inclusion criteria for the study, previously undiagnosed disorders of bone and mineral metabolism were identified in 55 women (32%). Disorders of calcium metabolism and hyperparathyroidism were the most frequent diagnoses. A testing strategy involving measurement of 24-h urine calcium, serum calcium, and serum PTH for all women and serum TSH among women on thyroid replacement therapy would have been sufficient to diagnose 47 of these 55 women (85%) at an estimated cost of $75 per patient screened. Previously undiagnosed disorders affecting the skeleton are common in otherwise healthy women with low bone density. A simple testing strategy is likely to identify most such disorders.

Modern parathyroid surgery: a cost-benefit analysis of localizing strategies.

HYPOTHESIS: Preoperative and intraoperative localizing techniques are more cost-effective than a nondirected bilateral neck exploration in the initial treatment of primary hyperparathyroidism (HPT). DESIGN: A clinical outcome model was developed to simulate the surgical management of primary HPT. Clinical scenarios modeled included a nondirected bilateral neck exploration and surgery using the following localizing strategies: preoperative technetium Tc 99m sestamibi scanning, intraoperative "quick" intact parathyroid hormone assay, or intraoperative radioguidance. Average total charges based on intent to treat were estimated from our practice and from the literature. MAIN OUTCOME MEASURES: Average total charges per patient (for the primary operation and for reexploration for persistent HPT, if needed), incidence of surgical failure (ie, persistent HPT), and risk of recurrent laryngeal nerve injury (cumulative risk of the primary procedure and a subsequent operation for persistent HPT). RESULTS: The use of any localizing strategy reduced total charges, risk of persistent HPT, and cumulative risk of recurrent laryngeal nerve injury compared with a nondirected bilateral neck exploration. The greatest cost savings and the lowest risk of recurrent laryngeal nerve injury were achieved when technetium Tc 99m sestamibi scanning was combined with intraoperative radioguidance. The lowest rate of persistent HPT was found when technetium Tc 99m sestamibi scanning was combined with an intraoperative parathyroid hormone assay. CONCLUSIONS: Limited parathyroid surgery using any localizing strategy is cost-effective, safe, and efficacious in the management of primary HPT. The cost benefit was primarily achieved by reduced operative charges and immediate hospital discharge rather than a lower need for reexploration for persistent HPT.

Screening for primary hyperparathyroidism before thyroid surgery: A prospective study.

BACKGROUND: Misdiagnosed primary hyperparathyroidism (PHPT) during thyroid surgery may lead to a difficult reoperation. Because PHPT is often asymptomatic, calcium measurements have been recommended before thyroid surgery, but no study has focused on the results of a prospective PHPT screening. METHODS: The prospective study of 748 patients consisted of 2-step screening of calcium measurement in all patients (normal range, 2.2 to 2.6 mmol/L, 8.8 to 10.4 mg/dL). If the calcium level was greater than 2.49 mmol/L (9.9 mg/dL), parathyroid hormone level (PTH; normal range, 11 to 65 pg/mL) and second calcium measurements were obtained. Positive screening was defined by 2 calcium levels greater than 2.49 mmol/L (9.9 mg/dL) and PTH level greater than 49 pg/mL. In patients with negative screening, we evaluated the number of parathyroid incidentalomas. In patients with positive screening, we rated parathyroid adenomas discovered as "easily accessible" or "requiring specific dissection." We assumed that the former could have been incidentally found by a surgeon unaware of calcium value. The cost estimation was based on French national health system databases. RESULTS: In the 9 patients with positive screening, 9 had parathyroid adenomas, 3 of them requiring specific dissection. In the 739 patients with negative screening, 12 had surgical incidentalomas and 2 had postoperative PHPT diagnosis. CONCLUSIONS: Our screening was not exhaustive, but it avoided a reoperation for missed PHPT in 3 patients. Population screening cost less than 3 reoperations. Other strategies, more exhaustive and/or cost-effective, should be investigated.

Effects of preoperative parathyroid localisation studies on the cost of operations for persistent hyperparathyroidism.

OBJECTIVE: To find out whether preoperative parathyroid localisation studies are cost-effective in patients with persistent hyperparathyroidism (HPT). DESIGN: Retrospective study. SETTING: University hospital, Sweden. PATIENTS: 29 consecutive patients with persistent HPT who were reoperated on with or without localisation studies. 15 other patients had initial operations for HPT without localisation studies. INTERVENTIONS: Initial or repeat operation for HPT, localisation studies with 99mTc sestamibi scintigraphy, and catheterisation of large cervical and mediastinal veins with measurements of serum concentrations of parathyroid hormone. MAIN OUTCOME MEASURES: Operative time. Cost of operations, frozen section biopsy and localisation studies. RESULTS: The mean durations of reoperation with localisation studies and for the initial operation without them, were 124 and 135 minutes, respectively, while it was 269 minutes for reoperation without studies. For patients who had localisation studies the mean total cost of the investigations, operating time, and frozen section biopsy was 28% less than for patients who were reoperated on without such studies. CONCLUSION: Preoperative localisation studies before repeat operations for HPT were cost-effective. Even if it has not been shown in this series, the reduction in operating time and the extent of dissection by localisation studies has the potential to decrease morbidity.

Unilateral versus bilateral neck exploration in parathyroid surgery: an assessment of 55 cases.

We retrospectively evaluated the cases of 55 patients who had undergone surgery for primary hyperparathyroidism at our institution to determine whether their parathyroid glands were abnormal on both sides. Thirty-six of these patients had undergone a bilateral neck exploration, and 19 had had a unilateral investigation. Of the 36 bilaterally explored patients, 30 had a solitary adenoma and no parathyroid pathology on the opposite side, five patients had hyperplastic glands with more than one gland involved, and one patient had two adenomas. In the unilaterally explored group, all 19 patients had a solitary adenoma. There were no failures in the way of persistent hypercalcemia in either group. Based on our findings, we conclude that a unilateral neck exploration should be performed during surgery for primary hyperparathyroidism whenever a large parathyroid adenoma and a normal parathyroid gland are found on the same side. Bilateral exploration should be reserved for patients in whom pathology cannot be found on the initially explored side during surgery and for patients who have obvious parathyroid hyperplasia.

Minimal incision parathyroidectomy: cure, cosmesis, and cost.

The goals of operative treatment of primary hyperparathyroidism are (1) cure; (2) minimal invasion; and (3) cost-effectiveness. The optimal strategy is controversial. Retrospective review of was undertaken 66 previously unoperated patients having minimal-incision, full-neck exploration by one surgeon over 29 months. A group of 51 women and 15 men had open full neck exploration under general anesthesia through a small (25-40 mm) incision using specifically selected instruments; patients remained hospitalized overnight. Preoperative sestamibi scans were obtained before referral for 17 patients: 11 had localized disease, and 6 did not (65% sensitivity). Four parathyroid glands were identified in 98% of patients; intraoperative frozen section was used selectively on a median of one gland per patient. About 76% of patients had single-gland disease, 6% had two-gland disease, and 18% had four-gland hyperplasia. One patient had four normal cervical parathyroid glands and an aortopulmonary window parathyroid adenoma resected at thoracotomy 1 week later; preoperative sestamibi scans failed to localize his disease. There were no nerve injuries and a 98% cure rate after initial cervical exploration. Excluding the cost of the sestamibi scans, there was no difference between those who had preoperative localization and those who did not; 60% of hospital costs were operating room time-related. Minimal-incision parathyroidectomy is effective for curing hyperparathyroidism and has excellent cosmetic results with negligible scar. Preoperative sestamibi scanning had no impact on cure or treatment costs. Strategies to improve cost-effectiveness must address the substantial costs of anesthesia and operating room services.

Success of preoperative imaging and unilateral neck exploration for primary hyperparathyroidism.

The surgical treatment of hyperparathyroidism has become controversial with the recent advent of reliable preoperative imaging modalities. This study examines the efficacy and economy of using preoperative imaging studies to localize the pathology and allow for unilateral neck exploration. From January 1990 to May 1996, a total of 91 patients with primary hyperparathyroidism were treated at Swedish Medical Center in Seattle, WA, by 2 surgeons. Eighty-six nuclear scintigraphy studies were performed, of which 44 were technetium 99m sestamibi (Tc-99m-sestamibi) scans and 42 were thallium 99m technetium (Th-99m-Tc) scans. The overall sensitivity for Tc-99m-sestamibi was 91% (40/44), and that for Th-99m-Tc scans was 81% (34/42). Ultrasound examination revealed a sensitivity of 80% (66/82). There was a statistically significant difference in surgical time between the unilateral and bilateral neck explorations (45 minutes, P < 0.0001). Unilateral neck exploration for hyperparathyroidism has been successful in curing hypercalcemia 93% (85/91) of the time with the use of preoperative imaging studies. Tc-99m-sestamibi is a reliable tool for planning the initial unilateral neck exploration for treatment of primary hyperparathyroidism.

Controversias en el diagnóstico y tratamiento del hiperparatiroidismo primario / Controversies in the diagnoses and treatment of primary hyperparathyroidism

Antecedentes: Una de las controversias en el manejo del hiperparatiroidismo primario es determinar la necesidad de estudios de localización, a la luz del costo-beneficio intraoperatorio que los mismos ofrecen. Lugar: Hospital de atención terciario dedicado al tratamiento de tumores. Objetivo: Demostrar si existe necesidad y ventajas de estudios previos. Diseño: Retrospectivo. Material y métodos: Se analizan los últimos 30 enfermos consecutivamente tratados. En todos, la calcemia y la paratohormona se hallaban elevados y la fosfatemia descendida. En 25/30 enfermos se realizaron estudios de localización, siendo la ecografía el de elección. En menor proporción se realizó rastreo con Selenio-metionina, TI201 y/o Tc99-Sestamibi. Resultados: Se halló adenoma en 23 e hiperplasia en 5. En 2 no se halló patología durante la 1º operación obligando a realizar estudios complementarios. En aquellos en que había coincidencia entre el estudio preoperatorio y el hallazgo intraoperatorio, la operación fue unilateral y demandó una media de 72 minutos. Cuando la exploración debió hacerse bilateralmente, la duración media fue de 110 minutos. El costo del estudio con Tc99-Sestamibi, es en nuestro medio de $ 150 (u$s 150). Conclusiones: Los estudios de localización no son imprescindibles pero facilitan la labor intraoperatoria. No obstante el porcentaje de éxito resulta similar. Si bien el tiempo operatorio desciende 30-45 minutos, el costo no es diferente con una u otra metodología

Cost implications of different surgical management strategies for primary hyperparathyroidism.

BACKGROUND: Controversy exists about optimal management of patients with primary hyperparathyroidism. To date, no studies have explored the cost implications of variation in practice. METHODS: Results from a national survey of endocrine surgeons were combined with results from a survey of endocrinologists and financial data from Medicare. Patterns of use of resources were identified, annual costs for the surgical management of primary hyperparathyroidism in the United States were calculated, and the financial impact of variation in practice was estimated. RESULTS: Survey respondents (n = 109) were experienced endocrine surgeons, performing an average of 33 parathyroidectomies annually. Seventy-five percent of patients undergo localization before initial exploration for primary hyperparathyroidism. In order of preference, these studies were sestamibi (43%), ultrasonography (28%), and sestamibi with single-photon emission computed tomography (26%). Although there is variation in preoperative and postoperative practice, in-hospital costs have the greatest influence on total cost. An estimated $282 million is spent annually in the United States on operations for primary hyperparathyroidism. National health expenditures could range by more than $70 million, depending on whether management strategies involving low or high use of resources are employed. CONCLUSIONS: Substantial variation among endocrine surgeons in the management of primary hyperparathyroidism has important cost implications. Implementation of evidence-based guidelines to optimize clinical and economic performance should be considered.

Initial cervical exploration for parathyroidectomy is not benefited by preoperative localization studies.

Published data is controversial as to the ability of preoperative localization studies (PLS) to enhance the outcome of initial cervical exploration in patients with primary hyperparathyroidism (PHPT). One surgeon's experience was reviewed to compare surgical success, operative time, and morbidity of initial cervical exploration for PHPT in patients who had undergone PLS versus those who had not. From August 1991 to September 1997, 95 patients who had not undergone prior central cervical exploration presented for surgical management of PHPT. Sixty-seven patients underwent initial cervical exploration without any PLS having been performed (Group A). Twenty-eight patients underwent PLS, either alone or in combination, before surgical intervention (Group B). Analysis of intergroup variability was conducted upon the data available using a two-tailed t test for independent samples. In addition, the sensitivities and positive predictive values of the PLS were calculated using study reports and operative and histologic findings. There was no statistically significant difference in surgical success between those patients who had PLS and those that did not undergo PLS. Sixty-four of 67 patients (95.5%) not having PLS were cured with initial surgery, while 27 of 28 patients (96.4%) who had PLS were surgically cured. Mean postoperative calcium and intact parathormone levels were similar between the two groups, and the mean operative time did not differ. Permanent hypocalcemia occurred in one patient, and five patients had transient hoarseness. Thirty-six total PLS were obtained at an average cost of $752.68/patient, and seven patients underwent multiple tests. Overall, sestamibi scan had the highest positive predictive value (81%). For adenomatous disease alone, sestamibi scan was the most sensitive (83%). Our study shows that for matched groups limited to age, sex, and clinical diagnosis, the use of PLS did not shorten operative time, decrease complication frequency, nor alter the success of the operation as measured by postoperative calcium and parathormone levels. Therefore, routine use of preoperative localization studies before initial cervical exploration for PHPT cannot be recommended.

[Decision analysis and clinical laboratory test in general internal medicine].

OVERVIEW: We demonstrated the quantitative approach to evaluating laboratory test in a patient with hypercalcemia. CASE DESCRIPTION: 43 year-old-woman was referred to our department because of sustained hypercalcemia without subjective symptoms in the past 5 years. Physical examination showed no abnormality with laboratory tests unremarkable except for hypercalcemia (10.8 mg/dl). DIFFERENTIAL DIAGNOSIS AND PRE-TEST PROBABILITY SETTING: Based on history and physical examination, we hypothesized two possible cases of hypercalcemia; primary parathyroidism (PHP) malignant disease (MD). The pre-test probability of PHP was set at 1/3, and that of MD at 2/3. CALCULATION AND ASSESSMENT: The post-test probability using the likelihood ratio of "albumin > 4.0 g/dl", 5.1 was increased to 0.72. However, it was not considered above the test-treatment threshold. We then measured Intact PTH which has a likelihood ratio 14. Intact PTH was increased yielding the post-test probability of 0.97. We considered that this value exceeded test-treatment threshold. The patient was referred to a surgical department. CONCLUSIONS: In daily practice, we, internists have to make clinical decisions quantitatively based on test results. To make a rational and quantitative approach to diagnostic tests clinical routine, it is mandatory to determine sensitivity and specificity of all laboratory tests used in our country.

[Nephrolithiasis--rational etiological assessment]. / Nephrolithiasis--Sinnvolle ätiologische Abklärungen.

Although underlying metabolic abnormalities do not differ fundamentally in patients with either first or recurrent nephrolithiasis and 35% of patients with a first event may have to face a recurrence 5 years later, extended metabolic investigations in patients with a first renal calculus should be restricted to particular, exceptional cases. However, in patients with a first calculus basic investigations with respect to specific causes for a concrement such as primary hyperparathyroidism, incomplete renal-tubular acidosis, recurrent urinary tract infection and cystinuria are mandatory. This includes, in addition to a laboratory investigation of blood and urine after a 2-hour-fasting period, analysis of the stone and a urography. The extended metabolic investigation in patients with recurrences or a first occurrence in a patients with a risk constellation includes evaluation of the most important lithogenic (calcium, oxalate, phosphate, uric acid) and inhibiting components (citrate) in the 24-hour urine, in patients with cystine calculi quantitation of cystine. A metabolic investigation should never be undertaken in the hospital or under standardized diet, but always under accustomed, unrestricted nutrition. At least 2 urine samples should be investigated from each patient, preferably not prior to 3-4 months after the event when homeostasis of the patient is restored analogously to the onset of concrement development.

Cost-effectiveness of preoperative localization studies in primary hyperparathyroid disease.

OBJECTIVE: To evaluate the effect of preoperative localization studies on the surgical management of patients with primary hyperparathyroid disease (PHPT). SUMMARY BACKGROUND DATA: Reported cure rates of initial surgical exploration for PHPT are close to 95%. Preoperative localization studies are frequently obtained to improve surgical success and decrease operative time. METHODS: Initial cervical exploration was performed in 113 patients with PHPT from 1981 to 1993. Twenty-four patients (21%) had surgery without preoperative localization studies. The remaining 89 patients (79%) had 132 noninvasive preoperative localization studies. Success of the localization studies in tumor localization, pathologic findings, postoperative serum calcium levels, and operative times were compared. Patient costs of the studies were calculated. RESULTS: Disease was identified during operation in 23 of 24 patients (96%) having cervical exploration without preoperative localization studies, and they had normal calcium levels after surgery. Eighty-seven of 89 patients (98%) having preoperative localization studies were surgically cured. The highest sensitivity rate (60%) and highest positive predictive value (79%) of the localization studies were found with thallium-technetium scintiscanning. Average cost of the localization studies was $901 per patient. Combination studies were obtained in 32 patients at an average cost of $1,314 per patient without improving sensitivity. Mean operating time did not differ for localized and nonlocalized patients. CONCLUSIONS: Preoperative localization studies did not improve parathyroid localization or cure rate and did not substantially shorten operating time in initial cervical exploration for PHPT. The economic burden of routine preoperative localization studies in these patients is not justified.