Is thymectomy necessary during parathyroidectomy for secondary hyperparathyroidism in patients with end-stage kidney disease?

Guidelines recommend thymectomy at the time of parathyroidectomy for secondary hyperparathyroidism to reduce the likelihood of persistent or recurrent disease. We sought to determine the frequency of thymectomy and explore its impact on recurrence of secondary hyperparathyroidism. Using TriNetX, a multi-institutional electronic health record and insurance claims network, we conducted a retrospective cohort study of adults with secondary hyperparathyroidism who underwent parathyroidectomy with or without thymectomy from 2005 to 2023. Rates of thymectomy, repeat parathyroidectomy, and calcimimetic use were compared between cohorts. Recurrence was defined by parathyroid hormone ≥600 pg/mL, reoperation, or calcimimetic use. Current Procedural Terminology and SNOMED codes for parathyroidectomy did not distinguish between subtotal compared with total parathyroidectomy. Among 2,564 patients underwent surgery for secondary hyperparathyroidism, 2,272 (88.8%) underwent parathyroidectomy and 287 (11.2%) underwent parathyroidectomy + thymectomy. Rates of parathyroidectomy + thymectomydecreased over time, from 25.5% in 2005 to 10.1% in 2023. Preoperatively, there was no difference in mean preoperative parathyroid hormone levels, serum calcium or calcidiol, or cinacalcet use. Postoperatively, there was no difference in the mean parathyroid hormone level (183 pg/mL vs 180 pg/mL, P = .88), odds of calcimimetic use (odds ratio, 0.94, 95% confidence interval, 0.64–1.39), reoperation within 5 years postoperatively (odds ratio 0.72, 95% confidence interval 0.39-1.36), or rates of kidney transplantation (odds ratio 1.03, 95% confidence interval 0.67-1.60) between parathyroidectomy and parathyroidectomy + thymectomy groups. Thymectomy is infrequently performed during parathyroidectomy for secondary hyperparathyroidism, and rates continue to decline. Although thymectomy at time of parathyroidectomy did not appear to decrease recurrence, future studies should include extent of parathyroidectomy to determine impact of thymectomy on recurrence in secondary hyperparathyroidism.