Study: CABG use decreased between 2001 and 2008
Epstein A. JAMA. 2011;305:1769-1776.
Results from an analysis published in JAMA suggested that CABG use decreased between 2001 and 2008, but also that percutaneous coronary intervention remained at stable levels.
Researchers for the cross-sectional study examined time trends in patients undergoing CABG or PCI between 2001 (n=77,952 for CABG; n=55,483 for PCI) and 2008 (n=151,893 for CABG; n=153,800 for PCI) in the Healthcare Cost and Utilization Project’s Nationwide Inpatient Sample. The data were supplemented by Medicare outpatient hospital claims.
According to the results, there was a 15% decrease in coronary revascularizations, from 5,569 (95% CI, 5,315-5,835) procedures/million-adults in 2001-2002 to 4,748 (95% CI, 4,532-4,975) procedures/million-adults in 2007-2008 (P<.001). Annual rates of annual CABG surgery decreased by 38%, from 1,742 (95% CI, 1,663-1,825) procedures/million-adults in 2001 to 1,081 (95% CI, 1,032-1,133) procedures/million-adults in 2008 (P<.001). The decreases were observed across sex, age racial and regional subgroups.
By contrast, annual rates of PCI decreased by 4%, from 3,827 (95% CI, 3,578-4,092) procedures/million-adults in 2001-2002 to 3,667 (95% CI, 3,429-3,922) procedures/million-adults in 2007-2008 (P=.74).
“Although the total rate of US coronary revascularization decreased modestly between 2001 and 2008, there was a substantial decrease in the CABG surgery rate,” the researchers concluded. “Between 2001 and 2008, the rate of PCI did not significantly change; however, there were continual changes in the frequency of stent types used for PCI.”
As we move forward into an era of limited health care resources, it will become increasingly important to have an accurate estimation of the clinical need and utilization of medical procedures. This information will enable forecasting of needs for resource allocation and decision-making about future investments in clinical infrastructure and training of future physicians.
In the study published by JAMA, Epstein et al estimate that rates of CABG have declined steadily by 15%, while PCI rates have declined only slightly, with a non-significant 4% decrease in 2008 compared with 2001. Although they claim that PCI volumes remained steady, their data show PCI procedures increased from 2001 to 2004, but decreased by 10% from 2005 to 2008.
Our similar study published in Circulation: Cardiovascular Quality and Outcomes also found a steady decrease in CABG, but a more complicated trend in PCI procedures. We reported annual CABG and PCI revascularization rates in the entire Medicare population from the beginning of 2000 through the end of 2009 and found an early increase in PCI procedures from 2000 to the end of 2004, but a steady decrease in PCI procedures from 2004 through 2009. Epstein et al also suggest a rise in multivessel stenting. Our data show that any increase multivessel stenting peaked in 2006, before publication of the SYNTAX study, and has since declined. Based on the rate of decrease in PCI, we concluded the decrease in CABG volume could not be entirely accounted for by a preferential use of PCI.
Epstein et al’s conclusion that PCI rates have remained unchanged must be evaluated closely. Both their study and ours show the changes in PCI volume were not steady over the 2000 to 2008 time period. However, their comparison between the 2001 and 2008 data assumes a linear change and, therefore, does not accurately reflect the trends that occurred in the intervening years.
The minor differences in the procedure rates published in our study result from use of different billing datasets and methodology. We utilized nearly complete Medicare physician billing data on inpatient and outpatient procedures, whereas Epstein et al evaluated all insurance types, but did not have data on outpatient procedures and made estimations of rates for their sample based on the US population, rather than the number of patients actually eligible for treatment in this subset of hospitals.
Importantly, Epstein et al acknowledge that the present study does not provide sufficient patient-level data to form any conclusions regarding procedural appropriateness. These revascularization rates may reflect changing patient demographics and clinical comorbidity within this sample of hospitals, rather than operator or patient preferences. An increase in acute coronary syndromes in numbers of patients with inoperable/high-risk surgical disease or low-risk non-surgical disease or the migration of patients from one hospital to another may explain their findings.
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FDA committees evaluate recent safety data on contrast agents
Members of the Cardiovascular and Renal Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee met today to interpret and discuss safety data for the two approved ultrasound contrast agents, Definity and Optison, as well as the investigational agent SonoVue. The FDA was not seeking advice on a vote to approve or revoke any of the agents but a discussion on current labeling.
The Cardiovascular and Renal Drugs Advisory Committee (CRDAC) had previously gathered in 2008 to examine efficacy and safety issues of those three agents.
According to background provided by the FDA, despite the appearance of a low overall adverse event rate with ultrasound contrast agents, serious adverse events and even fatalities still persist with all three agents. Although the organization noted the difficulty in distinguishing adverse events related to ultrasound contrast agents from concomitant medications and complications due to underlying comorbidities, it also said there is reason to believe ultrasound contrast agents play a contributory role.
In today’s meeting, both the CRDAC and the Drug Safety and Risk Management Advisory Committee convened at the request of the FDA to discuss in detail the safety data that have come to light in the 3 years since the meeting.
During the morning session, industry members from Lantheus Medical Imaging (Definity), GE Healthcare (Optison) and Bracco Diagnostics (SonoVue) presented post-marketing results on the safety studies performed on their respective agents. All of the studies presented showed minimal risk for serious adverse events related to usage of the agents, while also being consistent with the data presented at the previous meeting. As a result, both GE and Lantheus requested changes to the black box warnings, which they said are a barrier to use. The requested changes were either to remove the black lines or remove the warning completely.
Responding to this concern, Allan Coukell, BScPharm, director of medical safety, the Pew Health Group, Washington DC, said during the meeting, “It does seem there was a dip in use [of contrast agents] after the black box warning, but it’s come back up. It also seems clear that these agents are going to be used in ever-expanding settings by more and more people using them for the first time. So it seems to me that you would want them to know there is this [risk for a] rare but potentially very serious event.”
This led to one of the main issues discussed in the afternoon portion of the meeting which was the extent to which the new safety information presented justified modification of the boxed warnings. A consensus was not reached among members.
“The most positive thing I’ve heard today is of the impact of the black box warnings, in that it actually did something, maybe, which is unusual compared to drugs,” said Brian Strom, MD, MPH, chair and professor of biostatistics and epidemiology, University of Pennsylvania, Philadelphia. “But it’s important to keep in mind that black box warnings do not prohibit use. They are simply a way to clarify the risk/benefit balance. We are also in a climate now when more and more black box warnings are being added. Clearly, if you look at now, as opposed to five years ago, there is a lot more of them. To take it away now sends a clear message that we’ve seen data that changes the risk/benefit from what it was before seeing the data, and we haven’t. We’re all very clear on that. So if we haven’t seen anything to change it, it would send a really bad message that these agents are safer than we thought.”
However, Henry Black, MD, clinical professor of medicine, New York University School of Medicine, New York, was still not convinced there was a need for the warning and questioned why the black boxes were even added in the first place.
“It’s like an inflation creep, a grade creep. That’s why there are more black box warnings and why their impact becomes less and less; because they are not used appropriately,” he said. “I wasn’t at the 2008 meeting, [but the labeling’s] already been softened and there isn’t anything here. And I think it has an impact based on what we saw. I don’t think it’s going to affect things very much except in the legal environment we’re in where risk management to a hospital’s lease is so important that they are not going to go against this for obvious reasons that I think we ought to take this away.” – by Brian Ellis