Performance of Hospitals When Assessing Disease-Based Mortality Compared With Procedural Mortality for Patients With Acute Myocardial Infarction

Abstract [from journal]

Importance: Quality of percutaneous coronary intervention (PCI) is commonly assessed by risk-adjusted mortality. However, this metric may result in procedural risk aversion, especially for high-risk patients.

Objective: To determine correlation and reclassification between hospital-level disease-specific mortality and PCI procedural mortality among patients with acute myocardial infarction (AMI).

Design, Setting, and Participants: This hospital-level observational cross-sectional multicenter analysis included hospitals participating in the Chest Pain-MI Registry, which enrolled consecutive adult patients admitted with a diagnosis of type I non-ST-segment elevation myocardial infarction (NSTEMI) or ST-segment elevation myocardial infarction (STEMI), and hospitals in the CathPCI Registry, which enrolled consecutive adult patients treated with PCI with an indication of NSTEMI or STEMI, between April 1, 2011, and December 31, 2017.

Exposures: Inclusion into the National Cardiovascular Data Registry Chest Pain-MI and CathPCI registries.

Main Outcomes and Measures: For each hospital in each registry, a disease-based excess mortality ratio (EMR-D) for AMI was calculated, which represents a risk-adjusted observed to expected rate of mortality for AMI as a disease using the Chest Pain-MI Registry, and a procedure-based excess mortality ratio (EMR-P) for PCI was calculated using the CathPCI Registry.

Results: A subset of 625 sites participated in both registries, with a final count of 776 890 patients from the Chest Pain-MI Registry (509 576 men [65.6%]; 620 981 white [80.0%]; and median age, 64 years [interquartile range, 55-74 years]) and 853 386 patients from the CathPCI Registry (582 701 men [68.3%]; 691 236 white [81.0%]; and median age, 63 years [interquartile range, 54-73 years]). Among the 625 linked hospitals, the Spearman rank correlation coefficient between EMR-D and EMR-P produced a ρ of 0.53 (95% CI, 0.47-0.58), suggesting moderate correlation. Among the highest-performing tertile for disease-based risk-adjusted mortality, 90 of 208 sites (43.3%) were classified into a lower category for procedural risk-adjusted mortality. Among the lowest-performing tertile for disease-based risk-adjusted mortality, 92 of 208 sites (44.2%) were classified into a higher category for procedural risk-adjusted mortality. Bland-Altman plots for the overall linked cohort demonstrate a mean difference between EMR-P and EMR-D of 0.49% (95% CI, -1.61% to 2.58%; P < .001), with procedural mortality higher than disease-based mortality. However, among patients with AMI complicated by cardiogenic shock or cardiac arrest, the mean difference between EMR-P and EMR-D was -0.64% (95% CI, -4.41% to 3.12%; P < .001), with procedural mortality lower than disease-based mortality.

Conclusions and Relevance: This study suggests that, for hospitals treating patients with AMI, there is only a moderate correlation between procedural outcomes and disease-based outcomes. Nearly half of hospitals in the highest tertile of performance for PCI performance were reclassified into a lower performance tertile when judged by disease-based metrics. Higher rates of mortality were observed when using disease-based metrics compared with procedural metrics when assessing patients with cardiogenic shock and/or cardiac arrest, signifying what appears to be potential risk avoidance among this highest-risk subset of patients.