RVUs ‘inadequate’ in pediatric cath cases

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The relative value units (RVUs) used to reimburse physicians fall short in their ability to capture the time, skill and stress involved in catheterization procedures in children with congenital heart disease, according to a study published online Jan. 21 in Pediatrics.

RVUs are used by Medicare and often insurers to compensate physicians for their services, based on three components: physician work, practice expenses and cost of malpractice insurance. Services are defined through Current Procedural Terminology (CPT) codes. The RVU system is reassessed every five years to adjust for changes in practice and technology.

The physician work component includes the time spent, cognitive and technical skills and difficulty/stress. Lisa Bergersen, MD, MPH, of the Children’s Hospital Boston, and colleagues speculated that the CPT codes and corresponding RVUs for congenital heart operations might not accurately reflect the complexity involved in the care of pediatric patients.

“We considered that in the relatively young field of pediatric catheterization, where many of the procedures have only become common practice in the period since the inception of the RVU system, the CPT-based RVU system might be uniquely inadequate to measure the intended components of relative value,” they wrote.

To test their theory, they used the prospectively collected database at the Children’s Hospital Boston cath lab and identified quantifiable surrogates for the three components of the work RVU. The database provided patient and procedural characteristics, records of adverse events and a severity ranking that reflects complication. It also linked angiograms, interventions and types of diagnostic procedures performed to CPT codes.

For a time surrogate, they used case time; for cognitive skill, they chose radiation required, which they equated to the amount of information obtained and processed during the procedure; for technical skill, the number of interventions; and for stress, the incidence of adverse events.

They matched 2010 RVU values in the National Physician CMS Fee Schedule Relative Value File to corresponding CPT codes and then calculated RVU values for diagnostic, interventional and biopsy cases in the database that were performed between 2008 and 2010. The final sample totaled 3,557 cases.

They found that most cases involved complex congenital heart disease (39 percent), most were elective (80 percent) and the largest proportion was interventional (55 percent). The lowest risk category (38 percent) were mostly diagnostic cases for patients older than one year or undergoing myocardial biopsy. In the interventional cases, there was no correlation between RVU value, median procedure time, radiation dose or the predicted probability of an adverse event.

“[I]n the field of pediatric cardiac catheterization, RVU values did not capture intended elements of RVU (time, skill and stress) among interventional cases or discriminate among important differences by patient age,” Bergersen and colleagues wrote. “Thus, the established RVU system does not reflect all the intended elements of work for patients undergoing catheterization for congenital heart disease. We propose that either new RVUs are generated or additional metrics be considered when measuring the complexity of work in this pediatric specialty care service.”

They pointed out that there are few codes that capture the complexity and diversity of procedures performed in congenital cardiac catheterization heart disease, and that the codes have been developed for an adult patient population. Variability in intervention types as well as patient populations may explain the gap between RVU values and their findings on case duration, radiation dose and adverse events.  They noted that they also found a disconnect between RVU designations and age-related differences in risk in diagnostic procedures.

“Thus, in pediatric catheterization and perhaps other pediatric disciplines, age adjustment may need to be considered in assigning the relative value of work,” the authors suggested. They called for additional studies to evaluate the time, skill and stress expended in performing these procedures in children.  

The authors listed as limitations the fact that it was a single-center study and a convenience sample.