Positive Effect of Parathyroidectomy Compared to Observation on BMD in a Randomized Controlled Trial of Mild Primary Hyperparathyroidism

Mild or asymptomatic disease is now the dominating presentation of primary hyperparathyroidism (PHPT). However, bone involvement with decreased bone mineral density (BMD) and an increased risk of fractures has been demonstrated. Indications for parathyroidectomy (PTX) in mild PHPT have been debated for years. There is a need of long-term randomized studies comparing PTX with observation without intervention (OBS). Here, we present bone health data from the Scandinavian Investigation of Primary Hyperparathyroidism (SIPH), a randomized controlled trial, comparing PTX to OBS. This study included 191 patients (96 OBS/95 PTX), and 129 patients (64 OBS/65 PTX) were followed for 10 years to the end of study (EOS). BMD was measured with dual-energy X-ray absorptiometry (DXA), peripheral fractures were noted, and spine radiographs were obtained for vertebral fracture assessment. There was a significant treatment effect of PTX on BMD compared with OBS for all analyzed compartments, most explicit for the lumbar spine (LS) and femoral neck (FN) (p < 0.001). The mean changes in T-score from baseline to 10 years were from 0.41 for radius 33% (Rad33) to 0.58 for LS greater in the PTX group than in the OBS group. There was a significant decrease in BMD for all compartments in the OBS group, most pronounced for FN, Rad33, and ultradistal radius (UDR) (p < 0.001). Even though there was a significant treatment effect of PTX compared with OBS, there was only a significant increase in BMD over time for LS (p < 0.001). We found no difference between groups in fracture frequency in the 10-year cohort, neither with modified intention-to-treat (mITT) analysis nor per protocol analysis. Because BMD is only a surrogate endpoint of bone health and PTX did not reduce fracture risk, observation could be considered a safe option for many patients with mild PHPT regarding bone health in a 10-year perspective. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Mortality and Morbidity in Mild Primary Hyperparathyroidism: Results From a 10-Year Prospective Randomized Controlled Trial of Parathyroidectomy Versus Observation

BACKGROUND

Primary hyperparathyroidism (PHPT) is a common endocrine disorder associated with increased risk for fractures, cardiovascular disease, kidney disease, and cancer and increased mortality. In mild PHPT with modest hypercalcemia and without known morbidities, parathyroidectomy (PTX) is debated because no long-term randomized trials have been performed.

OBJECTIVE

To examine the effect of PTX on mild PHPT with regard to mortality (primary end point) and key morbidities (secondary end point).

DESIGN

Prospective randomized controlled trial. (ClinicalTrials.gov: NCT00522028).

SETTING

Eight Scandinavian referral centers.

PATIENTS

From 1998 to 2005, 191 patients with mild PHPT were included.

INTERVENTION

Ninety-five patients were randomly assigned to PTX, and 96 were assigned to observation without intervention (OBS).

MEASUREMENTS

Date and causes of death were obtained from the Swedish and Norwegian Cause of Death Registries 10 years after randomization and after an extended observation period lasting until 2018. Morbidity events were prospectively registered annually.

RESULTS

After 10 years, 15 patients had died (8 in the PTX group and 7 in the OBS group). Within the extended observation period, 44 deaths occurred, which were evenly distributed between groups (24 in the PTX group and 20 in the OBS group). A total of 101 morbidity events (cardiovascular events, cerebrovascular events, cancer, peripheral fractures, and renal stones) were also similarly distributed between groups (52 in the PTX group and 49 in the OBS group). During the study, a total of 16 vertebral fractures occurred in 14 patients (7 in each group).

LIMITATION

During the study period, 23 patients in the PTX group and 27 in the OBS group withdrew.

CONCLUSION

Parathyroidectomy does not appear to reduce morbidity or mortality in mild PHPT. Thus, no evidence of adverse effects of observation was seen for at least a decade with respect to mortality, fractures, cancer, cardiovascular and cerebrovascular events, or renal morbidities.

PRIMARY FUNDING SOURCE

Swedish government, Norwegian Research Council, and South-Eastern Norway Regional Health Authority.

Effects of Parathyroidectomy on Quality of Life: 10 Years of Data From a Prospective Randomized Controlled Trial on Primary Hyperparathyroidism (the SIPH-Study)

Primary hyperparathyroidism (PHPT) was previously considered a disease presenting with multiorgan involvement and a wide range of symptoms. Today, the disease presents with no symptoms or mild symptomatology in most patients. Data regarding nonspecific symptoms such as pain, fatigue, memory loss, depression, and other neuropsychiatric signs have been ambiguous, and results from prospective long-term randomized control trials are lacking. The Scandinavian Investigation on Primary Hyperparathyroidism (SIPH) is a prospective randomized controlled trial (RCT) with 10-year follow up, comparing parathyroidectomy (PTX) to observation without any treatment (OBS). From 1998 to 2005, 191 patients with mild PHPT were included from Sweden, Norway, and Denmark. A total of 95 patients were randomized to PTX and 96 to OBS. The generic Short Form-36 survey (SF-36) and the Comprehensive Psychopathological Rating Scale (CPRS) were studied at baseline, 2, 5, and 10 years after randomization. After 10 years, the PTX group scored significantly better on vitality (PTX 65.1 ± 20.2 versus OBS 57.4 ± 22.7; p = .017) compared to the OBS group in SF-36. We found no differences between the groups in the physical subscales. The OBS group had no significant change in any of the SF-36 scores throughout the study. The CPRS showed an improvement of symptoms in both groups for single items and sum scores after 10 years compared to baseline. There were, however, no significant differences between the two groups in the CPRS data. The results of this large and long-term RCT indicate improvement in some of the mental domains of SF-36 following PTX. However, the treatment effects between the groups were subtle with uncertain clinical significance. The observation group had stable SF-36 values and improvement in CPRS symptom-scores. Thus, in considering only quality of life (QoL) and in the absence of declines in renal and skeletal parameters, it may be safe to observe patients with mild PHPT for a decade. © 2020 American Society for Bone and Mineral Research (ASBMR).

The effect of surgery on fat mass, lipid and glucose metabolism in mild primary hyperparathyroidism

CONTEXT

Mild primary hyperparathyroidism has been associated with increased body fat mass and unfavorable cardiovascular risk factors.

OBJECTIVE

To assess the effect of parathyroidectomy on fat mass, glucose and lipid metabolism.

DESIGN, PATIENTS, INTERVENTIONS, MAIN OUTCOME MEASURES

119 patients previously randomized to observation (OBS; n = 58) or parathyroidectomy (PTX; n = 61) within the Scandinavian Investigation of Primary Hyperparathyroidism (SIPH) trial, an open randomized multicenter study, were included. Main outcome measures for this study were the differences in fat mass, markers for lipid and glucose metabolism between OBS and PTX 5 years after randomization.

RESULTS

In the OBS group, total cholesterol (Total-C) decreased from mean 5.9 (±1.1) to 5.6 (±1.0) mmol/L (P = 0.037) and LDL cholesterol (LDL-C) decreased from 3.7 (±1.0) to 3.3 (±0.9) mmol/L (P = 0.010). In the PTX group, the Total-C and LDL-C remained unchanged resulting in a significant between-group difference over time (P = 0.013 and P = 0.026, respectively). This difference was driven by patients who started with lipid-lowering medication during the study period (OBS: 5; PTX: 1). There was an increase in trunk fat mass in the OBS group, but no between-group differences over time. Mean 25(OH) vitamin D increased in the PTX group (P < 0.001), but did not change in the OBS group. No difference in parameters of glucose metabolism was detected.

CONCLUSION

In mild PHPT, the measured metabolic and cardiovascular risk factors were not modified by PTX. Observation seems safe and cardiovascular risk reduction should not be regarded as a separate indication for parathyroidectomy based on the results from this study.

Effect of Surgery Versus Observation: Skeletal 5-Year Outcomes in a Randomized Trial of Patients With Primary HPT (the SIPH Study)

Mild primary hyperparathyroidism (PHPT) is known to affect the skeleton, even though patients usually are asymptomatic. Treatment strategies have been widely discussed. However, long-term randomized studies comparing parathyroidectomy to observation are lacking. The objective was to study the effect of parathyroidectomy (PTX) compared with observation (OBS) on bone mineral density (BMD) in g/cm² and T-scores and on biochemical markers of bone turnover (P1NP and CTX-1) in a prospective randomized controlled study of patients with mild PHPT after 5 years of follow-up. Of 191 patients with mild PHPT randomized to either PTX or OBS, 145 patients remained for analysis after 5 years (110 with validated DXA scans). A significant decrease in P1NP (p < 0.001) and CTX-1 (p < 0.001) was found in the PTX group only. A significant positive treatment effect of surgery compared with observation on BMD (g/cm² ) was found for the lumbar spine (LS) (p = 0.011), the femoral neck (FN) (p < 0.001), the ultradistal radius (UDR) (p = 0.042), and for the total body (TB) (p < 0.001) but not for the radius 33% (Rad33), where BMD decreased significantly also in the PTX group (p = 0.012). However, compared with baseline values, there was no significant BMD increase in the PTX group, except for the lumbar spine. In the OBS group, there was a significant decrease in BMD (g/cm² ) for all compartments (FN, p < 0.001; Rad33, p = 0.001; UDR, p = 0.006; TB, p < 0.001) with the exception of the LS, where BMD was stable. In conclusion, parathyroidectomy improves BMD and observation leads to a small but statistically significant decrease in BMD after 5 years. Thus, bone health appears to be a clinical concern with long-term observation in patients with mild PHPT. © 2017 American Society for Bone and Mineral Research.

Effects of parathyroidectomy versus observation on the development of vertebral fractures in mild primary hyperparathyroidism

CONTEXT

Mild primary hyperparathyroidism (PHPT) is a common disease especially in middle-aged and elderly women. The diagnosis is frequently made incidentally and treatment strategies are widely discussed.

OBJECTIVE

To study the effect of parathyroidectomy (PTX) compared with observation (OBS) on biochemistry, safety, bone mineral density (BMD), and new fractures.

DESIGN

Prospective, randomized controlled study (SIPH study), with a 5-year follow-up.

SETTING

The study was conducted at multicenter, tertiary referral centers.

PATIENTS

Of 191 randomized patients with mild PHPT, biochemical data were available for 145 patients after 5 years, with a mean age at inclusion of 62.8 years (OBS group, 9 males) and 62.1 years (PTX group, 10 males).

INTERVENTION

Parathyroidectomy vs observation.

MAIN OUTCOME MEASURES

Biochemistry, BMD, and new radiographic vertebral fractures.

RESULTS

Serum-calcium and PTH-levels normalized after surgery and did not deteriorate by observation. BMD Z-scores were normal at inclusion in the lumbar spine (LS) and femoral neck (FN). For LS, BMD Z-scores were stable for 5 years with observation, but decreased in FN (P < .02). After surgery, BMD Z-scores increased significantly in both compartments (P < .02 for both), with a highly significant treatment effect of surgery compared to observation (P < .001). During follow-up, five new clinically unrecognized vertebral fractures were found in 5 females, all in the OBS group (P = .058).

CONCLUSION

Even though new vertebral fractures occurred only in the observation group, the frequency was not significantly different from the surgery group. Longer follow-up is needed before firm conclusions can be drawn about the long-term safety of observation, as opposed to surgery.

Secretion of parathyroid hormone after surgical trauma

Parathyroid hormone was measured in nine patients subjected to surgery under general anaesthesia not involving operative bone trauma. Total calcium concentration, ionized serum calcium and serum albumin was also analyzed pre- and post-operatively. An increase in serum parathyroid hormone was registered postoperatively without any accompanying decrease in ionized serum calcium. The measured changes are at present unexplained, but can be caused by other mechanisms than bone trauma.

Metabolic response to subtotal thyroidectomy in propranolol-treated thyrotoxic patients

Changes in plasma cortisol, glucose, cyclic AMP, blood leucocytes, pulse rate and body temperature were measured during and for 24 h after subtotal thyroidectomy in eight propranolol-treated (120-160 mg per day) mild to moderate thyrotoxic patients and eight patients with a non-toxic goitre. The results showed a similar metabolic response to surgery in the two groups without any trends towards a hypermetabolic response in the toxic group. The accumulating evidence of the safety of preoperative preparation with propranolol in patients with mild to moderate thyrotoxicosis is thus supported by our results.

Possible antagonists to gastrin in parathyroid adenomas

The high incidence of gastroduodenal ulcers in patients with hyperparathyroidism has been ascribed to gastric hyperacidity induced by hypercalcaemia. In a clinical study comprising 40 patients with solitary parathyroid adenoma, a negative correlation between serum calcium and spontaneous gastric acid secretion was found. At the same time a positive correlation was found between serum calcium and gastrin. It is concluded that gastric hyperacidity is not part of the syndrome provoked by parathyroid adenomas, and that a mechanism inhibitory to gastrin is active in these patients. It is suggested that the inhibitor could be calcitonin.

Glucagon stimulated plasma cyclic adenosine-3',5'-monophosphate in the differential diagnosis of jaundice

The amount of plasma cyclic adenosine-3',5'-monophosphate was estimated before and 15 minutes after the intravenous injection of 1 milligram of glucagon in 34 patients with obstructive and in 23 patients with nonobstructive jaundice. After stimulation with glucagon, the median adenosine-3',5'-monophosphate concentration in obstructive jaundice rose fortyfold or more, while in nonobstructive jaundice, the increase was twentyfold or less. The difference was highly significant. The results indicate that this test can be useful in the differential diagnosis of obstructive and nonobstructive jaundice.