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Age may impact hospital mortality rates in patients with acute MI

Hospital mortality rates for older patients with acute myocardial infarction do not always reflect the rates for younger patients, suggesting that younger adults should be incorporated into assessment of hospital outcomes to achieve the most accurate mortality ranking, according to recent findings published in Annals of Internal Medicine.

“Although 30-day [risk-standardized mortality rates (RSMRs)] indicate hospital quality for older patients, whether they also reflect quality for patients aged 64 years or younger is unknown. Despite this uncertainty, outcomes for Medicare beneficiaries are often used as a proxy for hospital quality,” Kumar Dharmarajan, MD, MBA, from Clover Health, Jersey City, N.J., and colleagues wrote. “If data from older patients do not reflect hospital quality more broadly, expanding quality and outcome measurement to include younger patients may be warranted.”

In the retrospective cohort study, researchers assessed the relationship between hospital 30-day RSMRs for older patients aged 65 years and older, younger patients aged 18 to 64 years, and all patients aged over 18 years with acute MI. They enrolled patients admitted to 986 hospitals in the ACTION Registry–Get With the Guidelines from Oct. 1, 2010, to Sept. 30, 2014.

Researchers used an electronic health record measure of acute MI mortality to calculate hospital 30-day RSMRs and also determined the hospital AMI achievement scores for all age groups. They ranked hospitals by their 30-day RSMRs, grouping hospitals as either top 20%, middle 60% and bottom 20%; top 10%, middle 80%, and bottom 10%; or better than expected, as expected and worse than expected per the CMS measurement algorithm.

Results showed 267,763 acute MI hospitalizations occurred in older patients and 276,031 occurred in younger patients. Median hospital 30-day RSMRs were 9.4% for older patients, 3% for younger patients and 6.2% for all patients.

Researchers also found that most top- and bottom-performing hospitals for older patients were not top or bottom performers for younger patients; however, most top and bottom performers for older patients were top and bottom performers for all patients. Hospital acute MI achievement scores for older patients correlated weakly with those for younger patients (r = 0.30), but correlated strongly with those for all patients (r = 0.92), according to the results.

The researchers concluded that hospital mortality rankings for older patients with acute MI inconsistently reflected those for younger patients.

“Our results support the need to incorporate younger patients into hospital outcome assessment. Data from younger patients are needed to examine the presence and effect of age-related differences in hospital quality,” Dharmarajan and colleagues wrote, adding that estimates of hospital quality using data from Medicare beneficiaries should not be assumed to reflect quality for younger persons, who constitute almost half of patients with acute MI.

In a related editorial, David W. Baker, MD, MPH, of the Joint Commission, Oakbrook, Ill., wrote that the poor correlation observed between hospital scores for older and younger patients with AMI may be due to a lack of variation in RSMRs for younger patients.

“Although the conclusion that hospital mortality rankings for older patients with [acute] MI inconsistently reflect those for younger patients is true, it belies the fact that hospital RSMR rankings for younger patients with [acute] MI are likely to be unstable and overly influenced by random variation because there are fewer deaths in this group,” Baker wrote.

“Although we should strive to include all patients in hospital measures of quality of care regardless of payer or data source, we must remember that measures should meet rigorous criteria for use in accountability programs before they are used at all,” he added. – by Savannah Demko

Disclosures: Baker reports no relevant financial disclosures. Dharmarajan reports a work contract with CMS and being a consultant and advisory board member for Clover Health. Please see the study for all other researchers’ relevant financial disclosures.