Validating the risk of hypoparathyroidism after total thyroidectomy in a population-based cohort: plea for improved follow-up.

BACKGROUND: A previous nationwide study from Sweden showed that the rate of permanent hypoparathyroidism is high and under-rated in the Swedish Quality Register. This retrospective population-based study aimed to validate the rate and diagnosis of permanent hypoparathyroidism found in the previous study. A secondary aim was to assess the relationship between the rate of low parathyroid hormone (PTH) levels within 24 h after surgery and the rate of permanent hypoparathyroidism. METHODS: All patients who underwent total thyroidectomy from 2005 to 2015 in a region of Sweden were included. Data were retrieved from local health records, the National Patient Registry, the Swedish Prescribed Drug Registry, and the Swedish Quality Register. A strict definition of permanent hypoparathyroidism was used, including biochemical data and attempts to stop the treatment. RESULTS: A total of 1636 patients were included. Altogether, 143 patients (8.7 per cent) developed permanent hypoparathyroidism. Of these, 102 (6.2 per cent) had definitive permanent hypoparathyroidism, whereas 41 (2.5 per cent) had possible permanent hypoparathyroidism, because attempts to stop the treatment were lacking (28) or patients were lost to follow-up (13). The agreement between the Swedish Quality Register and the chart review was 29.3 per cent. A proportion of 23.2 per cent with a PTH level below the reference value corresponded to a 6.7 per cent rate of permanent hypoparathyroidism. CONCLUSION: The risk of permanent hypoparathyroidism after total thyroidectomy is high. Some patients are overtreated because attempts to stop the treatment are lacking. Quality registers might underestimate the risk of permanent hypoparathyroidism. Approximately one-quarter of all patients with low PTH levels immediately after surgery developed permanent hypoparathyroidism.

The parathyroid glands control calcium levels in the blood. If they do not make enough hormone, calcium levels are low. Parathyroid dysfunction can happen after thyroid surgery, if the glands are hurt or removed by mistake. This is a problem because people with this condition may have symptoms and need ongoing treatment with vitamin D and calcium. They might also face other health issues and need regular visits to their doctor. Finding out how often long-term parathyroid dysfunction happens can be tricky because it requires a full year of follow-up and attempts to stop the treatment. This information is often missing from many studies and registers. Some recent studies have shown that this condition is more common than previously thought. It would be helpful to have a quick way to know how common long-term parathyroid gland dysfunction will be within a unit or hospital, without having to wait for the follow-up. This would help doctors to assess how good they are at taking care of patients. It would also support research on new methods to avoid parathyroid dysfunction. The goal of the study was to see how often long-term parathyroid dysfunction occurs after thyroid surgery, using a strict definition and complete long-term follow-up. Another aim was to assess the link between low parathyroid hormone levels right after surgery and the rate of long-term parathyroid dysfunction. All individuals who had the entire thyroid gland removed for benign disease between 2005 and 2015 in a region of Sweden were included. Data were collected from local health records at six hospitals. Patient information, surgical details, blood tests, and treatment details were gathered from the medical charts. Data were also collected from the national quality register. A high rate of long-term parathyroid dysfunction was seen in this large study of 1636 patients, Some patients may have been overtreated, because no attempts had been made to stop the treatment. The rate of long-term parathyroid dysfunction in patients with a normal early parathyroid hormone level was very low. About 23 per cent of all patients had a low early parathyroid hormone level, which corresponded to a 6.7 per cent rate of long-term parathyroid dysfunction. The authors believe that parathyroid hormone measurement could help predict the rate of permanent hypoparathyroidism, but more studies are needed to be sure.

Left-shifted relation between calcium and parathyroid hormone in Graves' disease.

BACKGROUND: Patients with Graves' disease (GD) have disturbances in calcium regulation with manifestations such as postoperative hypocalcemia. We have investigated the thyroid as well as the parathyroid function in detail. MATERIALS AND METHOD: A series of patients undergoing total thyroidectomy for GD (n = 56) or multinodular goiter (MNG; n = 50) were scrutinized for postoperative hypocalcemia and a need for calcium and/or vitamin D substitution. A citrate-calcium (CiCa) clamp was used in 14 patients and 21 controls to quantify the secretion of PTH in relation to the ionized plasma calcium level. The set point, equal to the plasma-ionized calcium concentration at which 50% of the maximal secretion of PTH is inhibited, as well as other CiCa-related parameters were calculated. RESULTS: Hypocalcemia was present in 48% of GD and 41.2% of patients with MNG postoperatively. Patients with GD had lower calcium levels, 18% had serum Ca less than 2.00 mmol/L compared with 4.0% in the MNG group (P = .02). A higher degree of GD patients were given parenteral calcium substitution during the hospital stay (3.6% vs 0 %) and oral calcium substitution at discharge (48% vs 10%), although they had normal vitamin D3 levels. The GD group showed a significantly left-shifted set point compared with the normal group on the CiCa clamp, 1.16 mmol/L vs 1.20 mmol/L (P < .001) as well as an increased PTH release to hypocalcemic stimulus. GD patients also show an association between degree of subclinical toxicosis at time of surgery and risk for developing postoperative hypocalcemia. CONCLUSION: Patients with GD demonstrate dysregulation of the calcium homeostasis by several parameters. GD patients have lower postoperative serum calcium compared with patients with MNG, lower calcium/PTH set point, and a significantly increased release of PTH to hypocalcemic stimulus compared with controls. The CiCa clamp response in GD patients with normal 25-hydroxyvitamin D3 levels mimics that of obese patients in which vitamin D insufficiency has been proposed as an underlying cause.

Management of Grave's disease is improved by total thyroidectomy.

BACKGROUND: A retrospective analysis was performed on 267 consecutive patients with Graves' disease (GD). The principal aim of this study was to evaluate the risk for recurrence and complications when changing the surgical method from subtotal (ST) to total thyroidectomy (TT). METHODS: Information from 267 consecutive patients operated on for GD between 2000 and 2006 was collected at Uppsala University Hospital (143) and Falun County Hospital (128). There were 229 women and 38 men. Four patients were operated on twice. A total of 40 STs and 229 TTs were performed. Results were compared to those of a previous cohort from the same hospital, with a majority of STs (157/176) performed from 1980 to 1992. RESULTS: The risk for relapse of GD was reduced from 20 to 3.3 % after the shift from ST to TT. In terms of surgical complications, 2.2 % demonstrated permanent vocal cord paralysis and 4.5 % had persistent hypocalcemia, not significant when compared to the previous cohort. In spite of TT, there were four recurrences, all due to remnant thyroid tissue high up at the hyoid bone. Changing the surgical method did not affect postoperative progression of dysthyroid ophthalmopathy (DO, 7.0 vs. 7.5 %). There were no differences in outcome with respect to which hospital the patients had their operation. CONCLUSION: Change from ST to TT dramatically reduced the risk for recurrence of GD without increasing the rate of complications. TT is not more effective than ST in hampering progression of DO as has been advocated by some. Careful surgical dissection up to the hyoid bone is necessary to avoid recurrence.