Urologist-Level Correlation in the Use of Observation for Low- and High-Risk Prostate Cancer.

Importance: The reporting of individual urologist rates of observation for localized prostate cancer may be a valuable performance measure with important downstream implications for patient and payer stakeholder groups. However, few studies have examined the urologist-level variation in the use of observation across all risk strata of prostate cancer.
Objectives: To measure variation in the use of observation at the urologist level by disease risk strata and to evaluate the association between the urologist-level rates of observation for men with low-risk and high-risk prostate cancer. Design, Setting, and Participants: With the use of linked Surveillance, Epidemiology, and End Results (SEER)-Medicare data, a population-based study of men diagnosed with prostate cancer from January 1, 2004, to December 31, 2009, was performed in SEER catchment areas of the United States. A total of 57 639 men with prostate cancer with 1884 diagnosing urologists were identified. Data were analyzed from October 1 to December 31, 2015. Main Outcomes and Measures: The main outcome was observation, which is defined as the absence of definitive treatment within 1 year of diagnosis. In each risk stratum, a multivariable mixed-effects model was fit to characterize associations between observation and selected patient characteristics. From these models, the estimated probability of observation was calculated for each urologist within each risk stratum, and the association between the physician-level estimated rates of observation for low-risk and high-risk disease was assessed.
Results: Among the 57 639 men included in the study, the estimated probability of observation for low-risk disease varied impressively (mean, 27.8%; range, 5.1%-71.2%) at the individual urologist level. Considerably less urologist-level variation was seen in the use of observation for intermediate-risk disease (11.1%; range, 4.8%-31.5%) and high-risk disease (5.8%; range, 3.2%-16.5%). Furthermore, the estimated rates of observation for low- and high-risk disease were correlated at the urologist level (Spearman ρ = 0.17; P < .001). A comparable correlation was likewise observed among urologists with high-volume prostate cancer practices (Spearman ρ = 0.24; P < .001). Conclusions and Relevance: Considerable urologist-level variation is seen in the use of observation for men with low-risk prostate cancer. More important, the use of observation for low-risk and high-risk patients with prostate cancer is correlated at the urologist level. This study reveals the strikingly variable use of observation among US urologists and establishes a framework for the use of urologist-level treatment signatures as a quality measure in the emerging value-based health care environment.