Trends in utilization of adrenalectomy in the United States: have indications changed?

Abstract

Minimally invasive approaches have dramatically reduced morbidity associated with adrenalectomy. There has been concern that an increased frequency of adrenal imaging along with the advantages of less morbidity could influence the indications for adrenalectomy. We tested the hypothesis that adrenalectomy has become more common over time and that benign diseases have been increasingly represented among procedural indications. The Nationwide Inpatient Sample (NIS) database was utilized to determine the incidence of adrenalectomy and the associated surgical indications in the United States between 1988 and 2000. All discharged patients were identified whose primary ICD-9-CM procedure code was for adrenalectomy, regardless of the specific surgical approach (laparoscopic adrenalectomy was not reliably coded). This subset was then queried for associated ICD-9-CM diagnostic codes. Linear regression and t-tests were utilized to determine the significance of trends. The total number of adrenalectomies increased significantly, from 12.9 per 100,000 discharges in 1988 to 18.5 per 100,000 discharges in 2000 (p = 0.000003). The total number of adrenalectomies with a primary ICD-9-CM code for malignant adrenal neoplasm did not increase significantly: from 1.2 per 100,000 discharges in 1988 to 1.6 per 100,000 discharges in 2000 (p = 0.47). The total number of adrenalectomies with a primary ICD-9-CM diagnostic code for benign adrenal neoplasm increased significantly, from 2.8 per 100,000 discharges in 1988 to 4.8 per 100,000 discharges in 2000 (p = 0.00002). The average percentage of adrenalectomies performed for malignant neoplasm was significantly higher during the period 1988--1993 when compared to 1994--2000 (11% vs. 9%; p = 0.002). The average percentage of adrenalectomies performed for benign neoplasm was significantly lower during 1988--1993 when compared to 1994--2000 (25% vs. 28%; p = 0.015). Adrenalectomy is being performed with increasing frequency. This is associated with an increase in the proportion of adrenalectomies performed for benign neoplasms. Assuming no significant change in disease prevalence during the study period, these data suggest that indications for adrenalectomy may have changed somewhat over that period.