Association of Work Measures and Specialty With Assigned Work Relative Value Units Among Surgeons

Abstract

Importance: The primary data sources used to generate and update work relative value units (RVUs) are surveys of small groups of specialists who are asked to estimate the time and intensity needed to perform surgical procedures. Because these surveys are conducted by specialty societies and rely on subjective data, these sources have been challenged as potentially biased.

Objective: To assess whether objective work measures are associated with a surgical procedure's assigned work RVUs and whether differences exist by surgical specialty.

Design, setting, and participants: This cross-sectional study obtained data from the 2016 and 2017 participant use files of the American College of Surgeons National Surgical Quality Improvement Program. The 2017 physician fee schedule of the Centers for Medicare & Medicaid Services was a secondary data source. Procedures were included if they had at least 100 patient-level observations over the 2-year period. Data were analyzed from August 29, 2018, to April 2, 2019.

Main outcomes and measures: The dependent variable was a procedure's assigned work RVU. Independent variables of work RVUs were 4 procedure-level work measures (median operative time, median postoperative length of stay, all-cause 30-day readmission rate, and all-cause 30-day reoperation rate) and surgeon specialty (10-level category using general surgery as the reference).

Results: The data set included 628 unique Current Procedural Terminology (CPT) codes and 726 CPT-specialty combinations from 1 239 991 patient observations. Statistically significant associations were found between each work measure and assigned work RVU, as follows: median operative time (R2 = 0.74; 95% CI, 0.71-0.78), postoperative length of stay (R2 = 0.42; 95% CI, 0.36-0.48), rate of readmission (R2 = 0.18; 95% CI, 0.13-0.23), and rate of reoperation (R2 = 0.15; 95% CI, 0.10-0.20). Including all 4 measures explained 80.2% (95% CI, 77.3%-83.1%) of the variation. Adding the surgical specialty improved the overall fit of the model (likelihood ratio test χ2 = 231.27; P < .001). Cardiac (7.78; 95% CI, 4.25-11.31; P < .001) and neurosurgery (2.46; 95% CI, 1.08-3.83; P < .001) had higher work RVUs compared with general surgery, whereas orthopedics (-1.53; 95% CI, -2.48 to -0.59; P = .002), urology (-1.58; 95% CI, -2.88 to -0.29; P = .02), plastics (-2.70; 95% CI, -4.39 to -1.01; P = .002), and otolaryngology (-3.05; 95% CI, -4.69 to -1.42; P < .001) had lower work RVUs compared with general surgery.

Conclusions and relevance: Objective work measures appeared to be associated with assigned work RVUs, predominantly with operative time; registry data can be used to augment and inform the generation and updating processes of the work RVUs.

Figure 1.. Flow Diagram of the Study Sample

CPT indicates Current Procedural Terminology.

Figure 2.. Bivariate Associations Between Procedure-Level Surgeon Work Measures and Assigned Work Relative Value Units (RVUs)

Because more than 1 specialty may perform a given surgical procedure, some Current Procedural Terminology (CPT) codes are duplicated. These CPT codes have the same assigned work RVUs but may have different work measures, depending on a specialty’s specific work measures.

Figure 3.. Association of Surgeon Specialty With Assigned Work Relative Value Units (RVUs)

Shown is a linear regression model with the assigned work RVU as the dependent variable with a 10-level categorical variable for specialty (reference: general surgery) as the primary independent variable. Covariates included the specialty-specific procedure median operative time; median postoperative length of stay; reoperation rate; and readmission rate, including quadratic terms when appropriate (full model is included in eTable 2 in the Supplement). Error bars represent the 95% CI around the point estimate. A specialty with an error bar completely to the right of the dotted vertical line may be interpreted as, after controlling for the available surgeon work measures, having higher mean work RVU values compared with general surgery. A specialty with an error bar entirely to the left of the dotted vertical line may be interpreted as, after controlling for the available surgeon work measures, having lower mean work RVU values compared with general surgery.