Association of Public Reporting for Percutaneous Coronary Intervention With Utilization and Outcomes Among Medicare Beneficiaries With Acute Myocardial Infarction FREE

Public reporting of patient outcomes is a key tool to drive improvements in health care delivery. Over the past 20 years, 3 states—New York (1991), Pennsylvania (2001), and Massachusetts (2005)—have instituted mandatory public reporting of outcomes for percutaneous coronary intervention (PCI). The idea behind public reporting is simple: collecting and publicly reporting performance will enable patients to choose high-quality hospitals and motivate clinicians to improve performance.

However, critics worry that public reporting may create disincentives for physicians and hospitals to care for the sickest patients, potentially leading clinicians to avoid offering lifesaving procedures to these patients.^1- 5 Prior research in this area, primarily focused on public reporting of coronary artery bypass graft (CABG) surgery outcomes, is nearly 2 decades old and has yielded mixed results.^6- 8 Over the course of the past 2 decades, PCI has overtaken CABG as a mainstay of therapy for ischemic heart disease.⁹ As a result, many states are now planning to implement public reporting for this procedure¹⁰—yet we are unaware of prior national studies examining whether public reporting of PCI outcomes is associated with lower PCI rates, especially among patients who might benefit from this procedure.

Therefore, we sought to examine the association between public reporting and rates of PCI among patients with acute myocardial infarction (MI). We focused on patients with MI because clinical trial data and guidelines support the use of PCI in this population.^11- 12 We sought to answer 3 questions. First, are patients with an acute MI less likely to receive a PCI in public reporting vs nonreporting states? Second, does this relationship vary with the risk profile of the patient (ie, if the patient presented with cardiogenic shock or cardiac arrest vs not)? Third, given that public reporting is meant to improve outcomes, is public reporting associated with lower mortality for patients with acute MI?

We used Medicare Provider Analysis and Review files from 2002 through 2010 to identify patients older than 65 years with a primary discharge diagnosis of acute MI, initial episode of care, using International Classification of Diseases, Ninth Revision (ICD-9) codes 410.x1. We defined the subgroup with non–ST-segment elevation myocardial infarction (NSTEMI) as patients with a primary diagnosis of subendocardial myocardial infarction (ICD-9 code 410.71), the subgroup with ST-segment elevation myocardial infarction (STEMI) as those with a primary diagnosis of STEMI (ICD-9 codes 410.x1, excluding 410.71), and the subgroup with cardiogenic shock or cardiac arrest as those with additional diagnostic codes for cardiogenic shock or cardiac arrest (ICD-9 codes 785.51 and 427.5, respectively). We also divided the sample into 2 age groups (65-74 and ≥75 years), based on current guidelines for use of PCI in the setting of STEMI.¹²

As is convention with prior work in this area, transferred patients were assigned to the receiving hospital. We only included patients with acute MI who were admitted or transferred to a hospital that was PCI capable in each of the study years.

The study was approved by the Harvard School of Public Health Office of Human Research Administration.

Massachusetts, Pennsylvania, and New York constituted the public reporting states for our primary analysis. Because of wide regional differences in practice patterns, we selected a regional control group consisting of the remaining New England and Mid-Atlantic states (Maine, Vermont, New Hampshire, Connecticut, Rhode Island, Maryland, and Delaware). We excluded New Jersey from our analyses because it has been collecting, but not reporting, data since 2007.

New York began to publicly report performance on PCI more than 2 decades ago (1991), and Pennsylvania began to report in 2001. Over the course of the past decade, only Massachusetts started to publicly report performance for PCI (with the first report coming out in late 2005). Therefore, for our longitudinal analysis, we only examined Massachusetts as our public reporting state, used the same control states as described above, and excluded New York and Pennsylvania from our analyses. We defined the prereporting period for this analysis as 2002 through 2004 and the postreporting period as 2006 through 2010, excluding 2005 because reporting began during that year.

Our primary outcome was receipt of a PCI (procedure codes 0066, 3601, 3602, 3605, 3606, 3607, 3609) during hospitalization for an acute MI. We calculated unadjusted PCI rates and ranked all states by the proportion of patients with acute MI in 2010 who received a PCI during their hospitalization. Then, to examine whether patients with an acute MI were less likely to receive a PCI in public reporting states compared with nonreporting states, we created patient-level hierarchical logistic regression models, first calculating the unadjusted odds of receiving a PCI in reporting vs nonreporting states. We then accounted for clustering of patients within hospitals, included a random effect for hospital, and calculated rates adjusted for age, sex, race, and 29 comorbid medical conditions using the Medicare risk adjustment model developed by the Agency for Healthcare Research and Quality (eTable 1). We repeated these analyses for cardiac catheterization (procedure codes 3722, 3723, 8855, 8856, 8857) and CABG surgery (procedure codes 3610-3619) as well as for a combined end point of PCI or CABG surgery.

In our longitudinal analysis, we again used patient-level hierarchical logistic regression models, first calculating unadjusted rates and odds and then creating fully adjusted models, and examined changes between the prereporting and postreporting periods in Massachusetts vs nonreporting states. We tested for interaction and repeated both the cross-sectional and the longitudinal models in each of our 3 cohorts based on risk (NSTEMI, STEMI, and cardiogenic shock or cardiac arrest) and the 2 cohorts based on age (65-74 years and ≥75 years), as well as for each of the procedural outcomes (PCI, catheterization, CABG surgery, and the combined end point of PCI or CABG).

We were also interested in whether public reporting led to better outcomes for the overall population of patients with acute MI as well as for the patients with acute MI who underwent PCI. Therefore, we calculated 30-day mortality rates using hierarchical logistic regression models, again both with and without adjustment for age, sex, race, and medical comorbid conditions using the Agency for Healthcare Research and Quality method. Unadjusted analyses account for concerns that public reporting states code comorbid conditions more aggressively, thus making patients in the public reporting states appear sicker than similar patients in the nonreporting states. We compared outcomes in public reporting vs nonreporting states in 2010. Next, we repeated longitudinal analyses, comparing outcomes in Massachusetts vs nonreporting states. In both cases, we repeated these models for all 3 risk cohorts and both age groups. Last, we repeated the mortality analyses stratified by receipt of PCI. We also performed sensitivity analyses using national controls (eTables 2–5).

Based on the baseline mortality rates in our data set, we had 90% power to detect a difference of 1.7% between the reporting states in cross-sectional analyses and 90% power to detect a difference in differences of 0.9% in longitudinal analyses. P < .05 was considered statistically significant. All analyses were conducted using SAS version 9.3.

Our patient population consisted of 97 802 discharges with a primary diagnosis of acute MI. In our cross-sectional cohort, patients in reporting states were slightly older; medical comorbid conditions were well-matched (Table 1). There were similar proportions of patients with NSTEMI, STEMI, and cardiogenic shock or cardiac arrest in public reporting and nonreporting states. Patient characteristics for the longitudinal cohort, as well as patient characteristics stratified by receipt of PCI, are available in eTables 6–8.

When we ranked the 50 US states and the District of Columbia by their proportion of patients with acute MI who received a PCI in 2010, the 3 public reporting states ranked 42nd (Pennsylvania), 48th (Massachusetts), and 50th (New York) (eFigure 1); patterns were similar for patients with cardiogenic shock or cardiac arrest (eFigure 2).

Among all patients admitted for an acute MI in 2010, those in public reporting states were significantly less likely to receive a PCI compared with the regional control group of patients in nonreporting states (unadjusted rates, 37.7% vs 42.7%; adjusted odds ratio [OR], 0.82 [95% CI, 0.71-0.93]; P = .003) (Table 2). This was most pronounced in the STEMI and the cardiogenic shock or cardiac arrest groups (P < .001 for interaction). The odds of receiving a PCI for patients in the NSTEMI group in public reporting states vs nonreporting states were similar (30.3% vs 33.7%; OR, 0.87 [95% CI, 0.73-1.04]; P = .12), whereas for the STEMI group (61.8% vs 68.0%; OR, 0.73 [95% CI, 0.59-0.89]; P = .002) and the cardiogenic shock or cardiac arrest group (41.5% vs 46.7%; OR, 0.79 [95% CI, 0.64-0.98]; P = .03), the odds were significantly lower. These differences were similar in the older (≥75 years) age group.

Patterns were very similar for the odds of receiving cardiac catheterization (unadjusted rates, 58.0% vs 62.8%; adjusted OR, 0.82 [95% CI 0.69-0.99]; P = .04) (eTable 9). There were no differences between reporting and nonreporting states in the odds of receiving CABG surgery (unadjusted rates, 8.3% vs 9.3%; adjusted OR, 1.01 [95% CI, 0.80-1.26]; P = .95) (Table 3).

We next examined changes in PCI rates in Massachusetts, the only state that initiated public reporting for PCI in the recent era. We found that through 2004, patients in Massachusetts and nonreporting states appeared to have comparable PCI rates. However, in 2005, the year in which Massachusetts began public reporting, the patterns began to diverge. By 2010, patients in Massachusetts appeared to have a lower likelihood of receiving a PCI than did patients in nonreporting states (Figure 1).

Using a difference-in-differences model, we found that the risk-adjusted odds of receiving a PCI changed in Massachusetts (compared with nonreporting states) after the advent of public reporting. In the prereporting period, patients in Massachusetts were similarly likely to undergo PCI when compared with patients in nonreporting states (unadjusted rates, 40.6% vs 41.8%; adjusted OR, 1.00 [95% CI, 0.71-1.41]) (Table 4). However, by the postreporting period, the odds of receiving PCI had decreased in Massachusetts relative to nonreporting states (41.1% vs 45.6%; OR, 0.81 [95% CI, 0.47-1.38]; P = .03 for difference in differences). These associations were most pronounced for patients with cardiogenic shock or cardiac arrest (P < .001 for interaction); for these patients, the relative odds of receiving a PCI in Massachusetts vs nonreporting states decreased significantly from the prereporting period (44.2% vs 36.6%; OR, 1.40 [95% CI, 0.85-2.32]) to the postreporting period (43.9% vs 44.8%; OR, 0.92 [95% CI, 0.38-2.22]) (P = .03 for difference in differences). We found comparable relationships in our group of older patients.

Patterns were similar for the odds of receiving cardiac catheterization (prereporting: unadjusted rates, 59.7% vs 63.2%; adjusted OR, 0.94 [95% CI, 0.63-1.42]; postreporting: 59.0% vs 67.0%; adjusted OR, 0.71 [95% CI, 0.38-1.31]; P = .006 for difference in differences) (eTable 10), suggesting that some decisions not to proceed took place prior to seeing patients' coronary anatomy. Over this same period, there was an increase in the odds of receiving CABG surgery in Massachusetts compared with nonreporting states (prereporting: unadjusted rates, 10.8% vs 12.9%; adjusted OR, 0.90 [95% CI, 0.64-1.21]; postreporting: 10.8% vs 11.1%; adjusted OR, 1.16 [95% CI, 0.67-1.90]; P = .01 for difference in differences) (Table 5 and Figure 2). This trend was driven primarily by a relative increase in the use of CABG surgery in the NSTEMI group (Table 5). When we summed the rates of PCI and CABG surgery, the differences in trends between Massachusetts and nonreporting states were somewhat attenuated (Figure 3).

We found no overall difference in 30-day mortality among patients with acute MI in public reporting vs nonreporting states (unadjusted rates, 12.8% vs 12.1%; adjusted OR, 1.08 [95% CI, 0.96-1.20]; P = .20) (Table 6). However, we did note higher mortality in the STEMI subgroup (13.5% vs 11.0%; OR, 1.35 [95% CI, 1.10-1.66]; P = .004).

Mortality was comparable in Massachusetts and nonreporting states prior to public reporting (unadjusted rates, 13.1% vs 13.9%; adjusted OR, 0.89 [95% CI, 0.77-1.02]) (Table 7). After the initiation of public reporting, we found no significant difference between Massachusetts and nonreporting states (11.7% vs 12.1%; OR, 0.99 [95% CI, 0.76-1.30]; P = .10 for difference in differences). These results were consistent across risk groups, in our older cohort, and in patients both undergoing and not undergoing PCI (eTable 11 and eTable 12).

We examined mandatory public reporting of patient outcomes for PCI and found that, compared with states without public reporting, states with reporting programs in place had substantially lower rates of PCI among patients with acute MI. The lower PCI rates were particularly pronounced for patients with STEMI, cardiogenic shock, or cardiac arrest. In Massachusetts, which adopted public reporting relatively recently, the initiation of public reporting was associated with a significant decrease in the odds of receiving PCI. We found no evidence that public reporting was associated with lower overall 30-day mortality rates for patients with acute MI.

There are at least 2 possible explanations for why public reporting was associated with lower rates of PCI for patients admitted for an acute MI. It is possible that many of the foregone procedures were futile or unnecessary, and public reporting focused clinicians on ensuring that only the most appropriate procedures were performed. Alternatively, public reporting may have led clinicians to avoid PCI in eligible patients because of concern over the risk of poor outcomes. Although policy makers have made efforts to ensure that risk adjustment models account for patient complexity, prior qualitative work suggests that clinicians remain concerned about receiving adequate “credit” for the comorbid conditions of their own patient population.¹ Our data cannot definitively differentiate between these 2 potential mechanisms.

Our findings of a relative increase in CABG rate in Massachusetts, in the setting of a decrease in PCI rate, suggests that there was at least a degree of substitution of one procedure for the other. This was particularly evident in the NSTEMI group, for whom CABG may be more easily substituted for PCI because of the lesser acuity of the patient population.

One way to ascertain whether the foregone procedures were appropriate is to examine mortality rates for patients with acute MI. In our analyses, we found that patients admitted for an acute MI had a somewhat higher mortality rate in public reporting states, although the differences were small, inconsistent, and usually not statistically significant. The weakness of this association suggests that the foregone procedures might have been a mix of appropriate and inappropriate PCIs. Another potential explanation for our mortality findings is that physicians in reporting states may have changed their coding practices in ways that made patients appear sicker than they actually were. These changes would likely bias our analyses away from finding an association between public reporting and worse outcomes. Therefore, although the lack of such an association is reassuring, new approaches are needed to definitively understand whether outcomes were different in public reporting states.

Strategies to help clinicians differentiate between patients likely to benefit from PCI and those for whom it would be futile are critically important. Promising work in this area is already under way.^13- 14 Providing real-time models of both risk and benefit may help physicians, patients, and families make more informed decisions about when to pursue PCI. Similarly, strategies to provide adequate credit for taking care of the sickest patients would also be useful. Massachusetts recently introduced a “compassionate use” category in their PCI reporting program that more accurately classifies patients at extremely high risk,¹⁵ and in 2008, New York began excluding patients in cardiogenic shock from its publicly reported outcomes.¹⁵ Whether these changes, instituted only recently, have been effective is not yet known. Follow-up data will be critical for determining if and how these policy changes influence patient selection for PCI.

Our findings are consistent with prior reports from single-state public reporting experiences. A study examining public reporting in the 1990s found that patients in New York were significantly less likely to undergo PCI after an acute MI than comparable patients in Michigan, a state without reporting.¹⁶ A more recent analysis of a small registry of patients in cardiogenic shock found that New York patients in shock were less likely than non–New York patients in shock to undergo PCI; in that study, the lower access to PCI was associated with higher mortality, although in a significantly younger population than in our study.³ Studies examining public reporting and access to CABG surgery have yielded more mixed results, with some studies suggesting decreased access^6,8 and others not demonstrating this relationship.⁷

Our study has several limitations. Although we focused our analyses on patients admitted for an acute MI, public reporting targeted all patients undergoing PCI, and we could not determine whether public reporting was associated with a mortality benefit for patients without MI. Of course, patients undergoing PCI for indications other than acute MI have very low mortality rates (0.65% in data from the National Cardiovascular Data Registry).¹⁴ There was substantial heterogeneity within the public reporting states. For example, 2 of the 3 states only reported outcomes for hospitals, whereas the third also reported outcomes for individual clinicians. Each state's system for adjudication and monitoring of data are different. One of the 3 reporting states (Massachusetts) expanded access to health insurance during the study period, which could have increased demand for PCI. Therefore, whether our results would be generalizable to all other states contemplating public reporting is unclear.

Because we used administrative data, we were unable to determine whether PCI was the most appropriate treatment in any specific clinical situation. However, indications for PCI should not be substantively different in public reporting states than in nonreporting states and should not have changed over time in Massachusetts. Furthermore, our use of administrative data limited our ability to fully account for potential up-coding by hospitals in public reporting states. We attempted to address this limitation by examining unadjusted outcomes. Additionally, any up-coding in the public reporting states should bias toward finding better outcomes after the advent of public reporting. Thus, our findings may actually underestimate the relationship between public reporting and PCI utilization or outcomes. Last, our analysis was limited to Medicare patients older than 65 years. Whether our findings would extend to a younger patient population is unclear.

We found that, among Medicare beneficiaries with acute MI, the use of PCI was lower for patients treated in 3 states with public reporting of PCI outcomes compared with patients treated in 7 regional control states without public reporting. These differences were particularly large in the highest-risk patients. However, we found no evidence that public reporting was associated with better overall mortality for patients with acute MI.