Epidemiological and Economic Trends in Inpatient and Outpatient Thyroidectomy in the United States, 1996-2006

Background: Traditionally, thyroid surgery has been an inpatient procedure due to the risk of several well-documented complications. Recent research suggests that for selected patients, outpatient thyroid surgery is safe and feasible, with the additional potential benefit of cost savings. In recognition of these observations, we hypothesized that there would be an increase in U.S. outpatient thyroidectomies with a concurrent decline in inpatient thyroidectomies over time. Methods: Comparative cross-sectional analyses of the National Survey of Ambulatory Surgery (NSAS) and Nationwide Inpatient Sample (NIS) databases from 1996 and 2006 were performed. All cases of thyroid surgery were extracted, as well as data on age, sex, and insurance status. Diagnoses and surgical cases were identified using International Classification of Diseases, Ninth Revision (ICD-9) diagnostic and treatment codes. Hospital charges were acquired from the NIS 1996 and 2006 and NSAS 2006 releases, using imputed data where necessary. After survey weights were applied, patient characteristics, diagnoses, and procedures were compared for inpatient versus outpatient procedures. Results: The total number of thyroidectomies increased 39%, from 66,864 to 92,931 cases per year during the study timeframe. Outpatient procedures increased by 61%, while inpatient procedures increased by 30%. The proportion of privately insured inpatients declined slightly from 63.8% to 60.1%, while those covered by Medicare increased from 22.8% to 25.8%. In contrast, the proportion of privately insured outpatients declined sharply from 76.8% to 39.9%, while those covered by Medicare rose from 17.2% to 45.7%. These trends coincided with a small increase in the mean inpatient age from 50.2 to 52.3 years and a larger increase in the mean outpatient age from 50.7 to 58.1 years. Inflation-adjusted per-capita charges for inpatient thyroidectomies more than doubled from $9,934 in 1996 to $22,537 in 2006, while aggregate national inpatient charges tripled from $464 million to $1.37 billion. By comparison, per-capita charges for outpatient thyroidectomy totaled $7,222 in 2006. Conclusions: From 1996 to 2006, there has been a concurrent modest increase in inpatient and pronounced increase in outpatient thyroidectomies in the United States, with a consequential demographic shift and economic impact.