Abstract and Introduction
Abstract
Objective: To determine the number of total thyroidectomies per surgeon per year associated with the lowest risk of complications.
Background: The surgeon volume–outcome association has been established for thyroidectomy; however, a threshold number of cases defining a "high-volume" surgeon remains unclear.
Methods: Adults undergoing total thyroidectomy were identified from the Health Care Utilization Project-National Inpatient Sample (1998–2009). Multivariate logistic regression with restricted cubic splines was utilized to examine the association between the number of annual total thyroidectomies per surgeon and risk of complications.
Results: Among 16,954 patients undergoing total thyroidectomy, 47% had thyroid cancer and 53% benign disease. Median annual surgeon volume was 7 cases; 51% of surgeons performed 1 case/y. Overall, 6% of the patients experienced complications. After adjustment, the likelihood of experiencing a complication decreased with increasing surgeon volume up to 26 cases/y (P < 0.01). Among all patients, 81% had surgery by low-volume surgeons (≤25 cases/y). With adjustment, patients undergoing surgery by low-volume surgeons were more likely to experience complications (odds ratio 1.51, P = 0.002) and longer hospital stays (+12%, P = 0.006). Patients had an 87% increase in the odds of having a complication if the surgeon performed 1 case/y, 68% for 2 to 5 cases/y, 42% for 6 to 10 cases/y, 22% for 11 to 15 cases/y, 10% for 16 to 20 cases/y, and 3% for 21 to 25 cases/y.
Conclusions: This is the first study to identify a surgeon volume threshold (>25 total thyroidectomies/y) that is associated with improved patient outcomes. Identifying a threshold number of cases defining a high-volume thyroid surgeon is important, as it has implications for quality improvement, criteria for referral and reimbursement, and surgical education.
Introduction
Thyroidectomy is one of the most commonly performed surgical procedures, with >130,000 thyroid operations done annually in the United States.[1] The procedure represents the principal treatment modality for both benign and malignant thyroid disease, such as hyperthyroidism, symptomatic goiter, indeterminate thyroid nodules, and thyroid cancer.
Surgical thyroid disease is an important public health issue. Thyroid nodules are now identified in as many as 68% of healthy adults;[2] this, in turn, has led to a significant increase in the number of thyroid biopsies performed and in the utilization of thyroidectomy.[1] The incidence of thyroid cancer has increased at a faster rate than any other malignancy in the United States, with 62,450 new diagnoses anticipated in 2015.[3] It is projected that thyroid cancer incidence will continue to rise to become the third most common cancer among women by 2019, surpassing colorectal and endometrial cancers.[4]
Although total thyroidectomy is generally safe, it can result in life-altering complications, such as recurrent laryngeal nerve injury, hematoma, and symptomatic hypoparathyroidism. Incidence of postoperative complications varies greatly depending on extent of surgery and, importantly, surgeon experience.[5,6] Published data have demonstrated that surgeons who perform more thyroidectomies have superior outcomes, with fewer complications, shorter hospitalization, and lower costs. Therefore, higher surgeon volume has been identified as an important predictor of improved outcomes after thyroidectomy.[7,8] However, the definition of a high-volume thyroid surgeon has remained unclear. Identification of a threshold number of cases defining a high-volume thyroid surgeon would be helpful for surgeons, referring physicians, and patients. Minimum case volume threshold has been incorporated by some professional societies into the credentialing process of physicians in other specialties, such as bariatric surgery and interventional cardiology.[9,10] In addition, identification of a surgeon volume threshold may have direct implications regarding the ongoing efforts for volume-based referral initiatives led by the Leapfrog Group—a growing consortium of >140 large public and private healthcare purchasers providing health benefit to >34 million Americans.[11] More recently, some major health systems in the United States have pledged to impose minimum-volume standards within their systems for certain procedures.[12]
Thus, we sought to determine if there is a minimum number of total thyroidectomies per surgeon per year that is associated, on average, with superior outcomes. Only total thyroidectomies were included in the analysis, as the surgeon volume–outcomes relation is less evident for thyroid lobectomy.[5,6] We hypothesize that there is a number of thyroidectomies performed by a surgeon per year that is associated with the lowest risk of complications.
Annals of Surgery. 2017;265(2):402-407. © 2017 Lippincott Williams & Wilkins
