Faculty Bibliography

BACKGROUND:Radiofrequency ablation is an alternative strategy for the management of benign thyroid conditions. We analyzed the proportion of patients who underwent thyroid surgery for benign conditions who would be potentially eligible for radiofrequency ablation. METHODS:We identified patients who underwent thyroid surgery from 2015 to 2019 at the study institution for Bethesda II cytopathology or toxic adenoma. Patients were considered potentially eligible for radiofrequency ablation if they had a dominant nodule >2 cm with or without compression symptoms, a dominant nodule <2 cm with compression symptoms, or a toxic adenoma. RESULTS:Of 411 patients in total, 284 (69.1%) would be eligible to consider thyroid radiofrequency ablation. In the radiofrequency ablation-eligible group, 20 (7.0%) experienced voice change after surgery, and 2 (0.7%) were dissatisfied or concerned about their scar. In the radiofrequency ablation-eligible group, 70 patients (24.6%) had malignancy diagnosed by final pathology, and 23 patients (8.1%) had cancers that were equal to or larger than 1 cm in size. CONCLUSION/CONCLUSIONS:Many patients who undergo surgery for benign thyroid disease could be considered for radiofrequency ablation as an alternative treatment modality. Given the rate of occult malignancy, optimal evaluation of nondominant nodules before radiofrequency ablation and long-term thyroid surveillance for patients who undergo radiofrequency ablation should be further studied.

BACKGROUND:Primary hyperparathyroidism historically necessitated bilateral neck exploration to remove abnormal parathyroid tissue. Improved localization allows for focused parathyroidectomy with lower complication risks. Recently, positron emission tomography using radiolabeled 18F-fluorocholine demonstrated high accuracy in detecting these lesions, but its cost-effectiveness has not been studied in the United States. METHODS:A decision tree modeled patients who underwent parathyroidectomy for primary hyperparathyroidism using single preoperative localization modalities: (1) positron emission tomography using radiolabeled 18F-fluorocholine, (2) 4-dimensional computed tomography, (3) ultrasound, and (4) sestamibi single photon emission computed tomography (SPECT). All patients underwent either focused parathyroidectomy versus bilateral neck exploration, with associated cost ($) and clinical outcomes measured in quality-adjusted life-years gained. Model parameters were informed by literature review and Medicare costs. Incremental cost-utility ratios were calculated in US dollars/quality-adjusted life-years gained, with a willingness-to-pay threshold set at $100,000/quality-adjusted life-year. One-way, 2-way, and threshold sensitivity analyses were performed. RESULTS:Positron emission tomography using radiolabeled 18F-fluorocholine gained the most quality-adjusted life-years (23.9) and was the costliest ($2,096), with a total treatment cost of $11,245 or $470/quality-adjusted life-year gained. Sestamibi single photon emission computed tomography and ultrasound were dominated strategies. Compared with 4-dimentional computed tomography, the incremental cost-utility ratio for positron emission tomography using radiolabeled 18F-fluorocholine was $91,066/quality-adjusted life-year gained in our base case analysis, which was below the willingness-to-pay threshold. In 1-way sensitivity analysis, the incremental cost-utility ratio was sensitive to test accuracy, positron emission tomography using radiolabeled 18F-fluorocholine price, postoperative complication probabilities, proportion of bilateral neck exploration patients needing overnight hospitalization, and life expectancy. CONCLUSION/CONCLUSIONS:Our model elucidates scenarios in which positron emission tomography using radiolabeled 18F-fluorocholine can potentially be a cost-effective imaging option for primary hyperparathyroidism in the United States. Further investigation is needed to determine the maximal cost-effectiveness for positron emission tomography using radiolabeled 18F-fluorocholine in selected populations.

BACKGROUND:F-fluorocholine positron emission tomography for preoperative parathyroid localization on patients with primary hyperparathyroidism. METHODS:F-fluorocholine positron emission tomography imaging was assessed using 3 anatomic locations (left neck, right neck, and mediastinum), with surgery as the gold standard. RESULTS:F-fluorocholine positron emission tomography (88.9%) outperformed both ultrasound (37.1%) and sestamibi (27.5%), as well as ultrasound and sestamibi combined (47.8%). CONCLUSION/CONCLUSIONS:F-fluorocholine positron emission tomography for parathyroid localization confirm its utility in a challenging cohort, with better sensitivity than ultrasound or sestamibi.

BACKGROUND:Guidelines recommend screening for primary aldosteronism in patients diagnosed with hypertension and obstructive sleep apnea. Recent studies have shown that adherence to these recommendations is extremely low. It has been suggested that cost is a barrier to implementation. No analysis has been done to rigorously evaluate the cost-effectiveness of widespread implementation of these guidelines. METHODS:We constructed a decision-analytic model to evaluate screening of the hypertensive obstructive sleep apnea population for primary aldosteronism as per guideline recommendations in comparison with current rates of screening. Probabilities, utility values, and costs were identified in the literature. Threshold and sensitivity analyses assessed robustness of the model. Costs were represented in 2020 US dollars and health outcomes in quality-adjusted life-years. The model assumed a societal perspective with a lifetime time horizon. RESULTS:Screening per guideline recommendations had an expected cost of $47,016 and 35.27 quality-adjusted life-years. Continuing at current rates of screening had an expected cost of $48,350 and 34.86 quality-adjusted life-years. Screening was dominant, as it was both less costly and more effective. These results were robust to sensitivity analysis of disease prevalence, test sensitivity, patient age, and expected outcome of medical or surgical treatment of primary aldosteronism. The screening strategy remained cost-effective even if screening were conservatively presumed to identify only 3% of new primary aldosteronism cases. CONCLUSIONS:For patients with hypertension and obstructive sleep apnea, rigorous screening for primary aldosteronism is cost-saving due to cardiovascular risk averted. Cost should not be a barrier to improving primary aldosteronism screening adherence.

BACKGROUND:Resistant hypertension is common in patients with primary aldosteronism and in those with obstructive sleep apnea. Primary aldosteronism treatment improves sleep apnea. Despite Endocrine Society guidelines' inclusion of sleep apnea and hypertension co-diagnosis as a primary aldosteronism screening indication, the state of screening implementation is unknown. METHODS:All hypertensive adult patients with obstructive sleep apnea (n = 4751) at one institution between 2012 and 2020 were compared with a control cohort without sleep apnea (n = 117,815). We compared the association of primary aldosteronism diagnoses, risk factors, and screening between both groups. Patients were considered to have screening if they had a primary aldosteronism diagnosis or serum aldosterone or plasma renin activity evaluation. RESULTS:Obstructive sleep apnea patients were predominantly men and had higher body mass index. On multivariable analysis, hypertensive sleep apnea patients had higher odds of drug-resistant hypertension (odds ratio [OR] 2.70; P < .001) and hypokalemia (OR 1.26; P < .001) independent of body mass index, sex, and number of antihypertensive medications. Overall, sleep apnea patients were more likely to be screened for primary aldosteronism (OR 1.45; P < .001); however, few patients underwent screening whether they had sleep apnea or not (pre-guideline publication 7.8% vs 4.6%; post-guidelines 3.6% vs 4.6%; P < .01). Screening among eligible sleep apnea patients remained low prior to and after guideline publication (4.4% vs 3.4%). CONCLUSIONS:Obstructive sleep apnea is associated with primary aldosteronism risk factors without formal diagnosis, suggesting screening underutilization and underdiagnosis. Strategies are needed to increase screening adherence, as patients may benefit from treatment of concomitant primary aldosteronism to reduce sleep apnea severity and its associated cardiopulmonary morbidity.

The purpose of this prospective study was to determine the correct localization rate (CLR) of ¹⁸F-fluorocholine PET for the detection of parathyroid adenomas in comparison to ^99mTc-sestamibi imaging. Methods: This was a single-arm prospective trial. Ninety-eight patients with biochemical evidence of primary hyperparathyroidism were imaged before parathyroidectomy using ¹⁸F-fluorocholine PET/MRI. ^99mTc-sestamibi imaging performed separately from the study was evaluated for comparison. The primary endpoint of the study was the CLR on a patient level. Each imaging study was interpreted by 3 masked readers on a per-region basis. Lesions were validated by histopathologic analysis of surgical specimens. Results: Of the 98 patients who underwent ¹⁸F-fluorocholine PET, 77 subsequently underwent parathyroidectomy and 60 of those had ^99mTc-sestamibi imaging. For ¹⁸F-fluorocholine PET in patients who underwent parathyroidectomy, the CLR based on the masked reader consensus was 75% (95% CI, 0.63-0.82). In patients who underwent surgery and had an available ^99mTc-sestamibi study, the CLR increased from 17% (95% CI, 0.10-0.27) for ^99mTc-sestamibi imaging to 70% (95% CI, 0.59-0.79) for ¹⁸F-fluorocholine PET. Conclusion: In this prospective study using masked readers, the CLR for ¹⁸F-fluorocholine PET was 75%. In patients with a paired ^99mTc-sestamibi study, the use of ¹⁸F-fluorocholine PET increased the CLR from 17% to 70%. ¹⁸F-fluorocholine PET is a superior imaging modality for the localization of parathyroid adenomas.

CONTEXT/BACKGROUND:The biochemical basis for clinical variability in primary hyperparathyroidism (PHPT) is poorly understood. OBJECTIVES/OBJECTIVE:To define parathyroid tumor biochemical properties associated with calcium sensing failure in PHPT patients, and to relate differences in these profiles to variations in clinical presentation. DESIGN/METHODS:Pre-operative clinical data were evaluated for correlation to parathyroid tumor biochemical behavior. SETTING/METHODS:An endocrine surgery referral center at a large, public university hospital. PATIENTS AND OTHER PARTICIPANTS/METHODS:A sequential series of 39 patients undergoing surgery for PHPT. MAIN OUTCOME MEASURES/METHODS:An intact tissue, ex vivo interrogative assay was employed to evaluate the calcium-sensing capacity of parathyroid adenomas relative to normal donor glands. Tumors were functionally classified based on calcium dose-response curve profiles, and clinical parameters were compared among the respective classes. Changes in the relative expression of CASR, RGS5, and RCAN1, three key components in the calcium/PTH signaling axis were evaluated as potential mechanisms for calcium-sensing failure. RESULTS:Parathyroid adenomas grouped into three distinct functional classes. Tumors with diminished calcium sensitivity were the most common (18 of 39) and were strongly associated with reduced bone mineral density (p=0.0009). Tumors with no calcium sensing deficit (11 of 39) were associated with higher pre-operative PTH (p = 0.036). A third group (6/39) displayed a non-sigmoid calcium/PTH response curve; four of these six tumors expressed elevated RCAN1. CONCLUSIONS:Calcium-sensing capacity varies among parathyroid tumors but down-regulation of the calcium sensing receptor (CASR) is not an obligate underlying mechanism. Differences in tumor calcium responsiveness may contribute to variations in PHPT clinical presentation.

OBJECTIVE:Patients with primary hyperparathyroidism (PHPT) are at increased risk of kidney stones. Guidelines recommend parathyroidectomy in patients with PHPT with a history of stone disease. This study aimed to compare the 5-year incidence of clinically significant kidney stone events in patients with PHPT treated with parathyroidectomy versus nonoperative management. METHODS:We performed a longitudinal cohort study of patients with PHPT in a national commercial insurance claims database (2006-2019). Propensity score inverse probability weighting-adjusted multivariable regression models were calculated. RESULTS:We identified 7623 patients aged ≥35 years old with continuous enrollment >1 year before and >5 years after PHPT diagnosis. A total of 2933 patients (38.5%) were treated with parathyroidectomy. The cohort had a mean age of 66.5 years, 5953 (78.1%) were female, and 5520 (72.4%) were White. Over 5 years, the unadjusted incidence of ≥1 kidney stone event was higher in patients who were managed with parathyroidectomy compared with those who were managed nonoperatively overall (5.4% vs 4.1%, respectively) and among those with a history of kidney stones at PHPT diagnosis (17.9% vs 16.4%, respectively). On multivariable analysis, parathyroidectomy was associated with no statistically significant difference in the odds of a 5-year kidney stone event among patients with a history of kidney stones (odds ratio, 1.03; 95% CI, 0.71-1.50) or those without a history of kidney stones (odds ratio, 1.16; 95% CI, 0.84-1.60). CONCLUSION/CONCLUSIONS:Based on this claim analysis, there was no difference in the odds of 5-year kidney stone events in patients with PHPT who were treated with parathyroidectomy versus nonoperative management. Time horizon for benefit should be considered when making treatment decisions for PHPT based on the risk of kidney stone events.

BACKGROUND:Accurate prediction of thyroidectomy complications is necessary to inform treatment decisions. Ensemble machine learning provides one approach to improve prediction. METHODS:We applied the Super Learner (SL) algorithm to the 2016-2018 thyroidectomy-specific NSQIP database to predict complications following thyroidectomy. Cross-validation was used to assess model discrimination and precision. RESULTS:For the 17,987 patients undergoing thyroidectomy, rates of recurrent laryngeal nerve injury, post-operative hypocalcemia prior to discharge or within 30 days, and neck hematoma were 6.1%, 6.4%, 9.0%, and 1.8%, respectively. SL improved prediction of thyroidectomy-specific outcomes when compared with benchmark logistic regression approaches. For postoperative hypocalcemia prior to discharge, SL improved the cross-validated AUROC to 0.72 (95%CI 0.70-0.74) compared to 0.70 (95%CI 0.68-0.72; p < 0.001) when using a manually curated logistic regression algorithm. CONCLUSION/CONCLUSIONS:Ensemble machine learning modestly improves prediction for thyroidectomy-specific outcomes. SL holds promise to provide more accurate patient-level risk prediction to inform treatment decisions.

Importance/UNASSIGNED:Parathyroidectomy provides definitive management for primary hyperparathyroidism (PHPT), reducing the risk of subsequent fracture, nephrolithiasis, and chronic kidney disease (CKD), but its use among older adults in the US is unknown. Objective/UNASSIGNED:To identify patient characteristics associated with the use of parathyroidectomy for the management of PHPT in older adults. Design, Setting, and Participants/UNASSIGNED:This population-based, retrospective cohort study used 100% Medicare claims from beneficiaries with an initial diagnosis of PHPT from January 1, 2006, to December 31, 2016. Patients were considered to meet consensus guideline criteria for parathyroidectomy based on diagnosis codes indicating osteoporosis, nephrolithiasis, or stage 3 CKD. Multivariable logistic regression was used to identify patient characteristics associated with parathyroidectomy. Data were analyzed from February 11, 2020, to October 8, 2020. Main Outcomes and Measures/UNASSIGNED:The primary outcome was parathyroidectomy within 1 year of diagnosis. Results/UNASSIGNED:Among 210 206 beneficiaries with an incident diagnosis of PHPT (78.8% women; mean [SD] age, 75.3 [6.8] years), 63 136 (30.0%) underwent parathyroidectomy within 1 year of diagnosis. Among the subset of patients who met consensus guideline criteria for operative management (n = 131 723), 38 983 (29.6%) were treated with parathyroidectomy. Patients treated operatively were younger (mean [SD] age, 73.5 [5.7] vs 76.0 [7.1] years) and more likely to be White (90.1% vs 86.0%), to be robust or prefrail (92.1% vs 85.7%), and to have fewer comorbidities (Charlson Comorbidity Index score of 0 or 1, 54.6% vs 44.1%), in addition to being more likely to live in socioeconomically disadvantaged (46.9% vs 40.3%) and rural (18.1% vs 13.6%) areas (all P < .001). On multivariable analysis, increasing age had a strong inverse association with parathyroidectomy among patients aged 76 to 85 years (unadjusted rate, 25.9%; odds ratio [OR], 0.68 [95% CI, 0.67-0.70]) and older than 85 years (unadjusted rate, 11.2%; OR, 0.27 [95% CI, 0.26-0.29]) compared with those aged 66 to 75 years (unadjusted rate, 35.6%), as did patients with moderate to severe frailty (unadjusted rate, 18.9%; OR, 0.60 [95% CI, 0.56-0.64]) compared with robust patients (unadjusted rate, 36.1%) and those with a Charlson Comorbidity Index score of 2 or greater (unadjusted rate, 25.9%; OR, 0.77 [95% CI, 0.75-0.79]) compared with a Charlson Comorbidity Index score of 0 (unadjusted rate, 37.0%). With regard to operative guidelines, a history of nephrolithiasis increased the odds of parathyroidectomy (OR, 1.43 [95% CI, 1.39-1.47]); stage 3 CKD decreased the odds of parathyroidectomy (OR, 0.71 [95% CI, 0.68-0.74]); and osteoporosis showed no association (OR, 1.01 [95% CI, 0.99-1.03]). Conclusions and Relevance/UNASSIGNED:In this cohort study, most older adults with PHPT did not receive definitive treatment with parathyroidectomy. Older age, frailty, and multimorbidity were associated with nonoperative management, and guideline recommendations had minimal effect on treatment decisions. Further research is needed to identify barriers to surgical care and develop tools to target parathyroidectomy to older adults most likely to benefit.