To elucidate the evolving trends in subspecialization related to individual practice within inpatient urology over a 31-year period spanning from 1982 to 2012.

We conducted a retrospective cohort study by querying the centralized New York State data on partial nephrectomy, radical nephrectomy, radical prostatectomy, and radical cystectomy procedures for all inpatient encounters in the state of New York for the years 1982-2012 using the Statewide Planning and Research Cooperative System dataset. All encounters involving 1 of the procedures were identified and the AMA Masterfile was used to identify all physicians who have completed residencies in urology. We performed descriptive analyses to determine the quantity of cases, quantity of patients, and distribution of the cases among operating physicians. High-volume urologists, defined as the top 5% of urologists in terms of caseload, were identified, and the distributions of their procedures was analyzed.

The proportion of procedures completed by high-volume urologists increased significantly for all procedures. The number of identified urologists involved in radical cystectomy and radical nephrectomy has declined since 1982, with the number of identified urologists involved in partial nephrectomy and radical prostatectomy beginning a continuous decline from 2004 to 1999, respectively. During the 31-year time period, the number of cases increased for all procedures.

A smaller group of urologists is performing a larger proportion of cases for each studied procedure, reflecting a trend toward subspecialization.