Post-AMI Hospital Mortality Rates Differ by Age in NCDR Study

Outcomes for older patients who are hospitalized for acute myocardial infarction (AMI) are used by the Centers of Medicare and Medicaid Services (CMS) to calculate and publicly report hospitals' 30-day risk-standardized mortality rates (RSMR). However, a retrospective cohort study published Sept. 26 in Annals of Internal Medicine shows these RSMRs may not be representative of mortality rates for younger patients and may have an impact on a hospital's overall quality improvement efforts for AMI patients.

Led by Kumar Dharmarajan, MD, MBA, et al., the study analyzed data from 968 hospitals in ACC's ACTION Registry. They identified 543,794 adult hospitalizations between Oct. 1, 2010 and Sept. 30, 2014. When stratified by age, the total study population was split in nearly equal halves: 267,763 hospitalizations involved older patients (≥65 years) and 276,031 involved younger patients (18-64 years). The average age was 64.8 years among all patients, 76.3 years among older patients and 53.6 among younger patients. Upon admission, older patients were more likely to have acute heart failure, but less likely to have STEMI compared with younger patients (p < 0.001 each).

Researchers calculated mortality rates within 30 days of readmission based on age and correlated hospital AMI achievement scores for each age group by applying CMS' Hospital Value-Based Purchasing (HVBP) Program method. Older patients had the highest median hospital 30-day RSMRs at 9.4 percent, bringing the total patient population's RSMR up to 6.2 percent. Younger patients had a 3 percent RSMR. A similar correlation was found among resulting HVBP achievement scores; scores for older patients correlated more strongly with those for all patients (R = 0.92) than with score for younger patients (R = 0.30).

Interestingly, most of the top- and bottom-performing hospitals for older patients ranked differently for younger patients. "The assumption that the outcomes of younger patients parallel those of older patients within a hospital does not hold up," says Jeptha Curtis, MD, one of the study co-authors.

"We can't assume signals of quality for older adults are generalizable. We need to understand hospital quality for younger adults as well," adds Kumar Dharmarajan, MD. One reason why more data is more available on older patients is the fact that it is derived from Medicare records. With younger patients, however, clinical data exist in databases of individual health plans or hospitals, making it harder to link. Efforts have begun among states, but no centralized database exists in the United States.

"The lack of focus on hospital outcomes for younger patients is a missed opportunity because initial hospital quality for AMI may influence long-term mortality," state the study authors. "Stratified reporting of quality measures with separate estimates of hospital quality for younger and older patients would permit further examination of the presence and effect of age-related differences in hospital quality."

Clinical Topics: Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: United States, Hospital Mortality, Medicaid, Value-Based Purchasing, Quality Improvement, Patient Readmission, Research Personnel, Centers for Medicare and Medicaid Services (U.S.), Retrospective Studies, Medicare, Hospitalization, Patient Admission, Hospitals, Registries, Heart Failure

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