Validity of hospital rankings for MI, readmissions

Summaries from ACP Hospitalist Weekly.

Patient age appears to impact hospital quality rankings for myocardial infarction care

Hospital rankings based on myocardial infarction (MI) mortality rates only for older patients may not be applicable to all patients, according to a recent study.

CMS calculates 30-day risk-standardized mortality rates (RSMRs) after acute MI in Medicare fee-for-service beneficiaries ages 65 years and older to rate the quality of hospitals. Researchers used data from 986 hospitals in the ACTION (Acute Coronary Treatment and Intervention Outcomes Network) Registry-Get With the Guidelines to perform a retrospective cohort study of the relationship between 30-day hospital RSMRs for older patients, younger patients, and all patients with acute MI. Older patients were those ages 65 years and older, younger patients were those ages 18 to 64 years, and all patients were those 18 years of age and older.

The authors calculated RSMRs for each age group using a National Quality Forum-endorsed electronic health record (EHR) measure of acute MI mortality, ranked hospitals accordingly by age group, and plotted agreement in rankings. In addition, correlation in hospital acute MI achievement scores was calculated with the EHR measure using the Hospital Value-Based Purchasing Program method. The study results were published by Annals of Internal Medicine on Sept. 26, 2017.

The analysis included 267,763 hospitalizations for acute MI among older patients and 276,031 among younger patients. The average patient age was 76.3 years for older patients, 53.6 years for younger patients, and 64.8 years for all patients. For older, younger, and all patients, median hospital 30-day RSMRs were 9.4%, 3.0%, and 6.2%, respectively. Hospitals that were good or poor performers among older patients were not necessarily good or poor performers among younger patients, although most were good or poor performers among all patients. In addition, a weak correlation was seen between achievement scores in older patients and younger patients, but a strong correlation was seen between achievement scores in older patients and all patients.

The authors noted that the included hospitals were only a small sample of those in the U.S. that treat acute MI and that mortality rates were low and 30-day RSMR ranges limited in younger patients, among other limitations. However, they concluded that hospital mortality ratings for older patients with acute MI do not consistently reflect rankings for younger patients.

“Estimates of hospital quality using data from Medicare beneficiaries should therefore not be assumed to reflect quality for younger persons, who constitute almost half of patients with [acute] MI,” the authors wrote. “Additional outcome measurement beyond Medicare beneficiaries may be required to understand and report care quality more broadly within hospitals.”

An accompanying editorial by an author from The Joint Commission noted that quality differences might actually reflect differences in acute MI subtype or comorbid conditions, since older patients were less likely to have ST-segment elevation at presentation and much more likely to have acute heart failure. The editorialist also pointed out that the poor correlation between hospital scores for older and younger patients is most likely due to the relative lack of variation in RSMRs in the latter group. It should not be assumed that a hospital's ranking reflects its actual quality of care versus similar hospitals due to possibly inadequate adjustment for differences in case-mix, the editorialist wrote. “Although we should strive to include all patients in hospital measures of quality of care regardless of payer or data source,” he wrote, “we must remember that measures should meet rigorous criteria for use in accountability programs before they are used at all.”

Readmission risk differs when same Medicare patients admitted to different hospitals

Readmission rates are an indicator of hospital quality, according to a recent analysis of patients hospitalized at multiple hospitals.

Researchers created two cohort samples from Medicare beneficiaries 65 years of age and older hospitalized any time from July 2014 through June 2015. The first was used to calculate risk-standardized 30-day readmission rates for each hospital and divide the hospitals into performance quartiles. The second sample included patients who had two admissions for similar diagnoses that occurred more than one month but less than a year apart at different hospitals. Results were published in the Sept. 14, 2017, New England Journal of Medicine.

In the first sample, the median readmission rate was 15.5% (interquartile range, 15.3% to 15.8%). In the second sample, there were 37,508 patients admitted to 4,272 hospitals and their risk of readmission was consistently higher if they were admitted to one of the hospitals in the worse quartiles for readmissions than if they were admitted to a hospital in a better quartile. However, the difference between hospitals achieved significance only when patients had an admission to a hospital in the best quartile and to a hospital in the worst quartile (absolute difference in readmission rate, 2.0 percentage points; 95% CI, 0.4 to 3.5 percentage points; P=0.001).

“This study addresses a persistent concern that national readmission measures may reflect differences in unmeasured factors rather than in hospital performance,” and the results “suggest that hospital quality contributes in part to readmission rates independent of factors involving patients,” the authors said. The two-point difference in readmission risk might seem small, but it works out to an additional readmission for every 50 patients admitted to a hospital in the lowest quartile, they calculated.

The study's results “may reassure the public, policymakers, and health care professionals that the signal of quality from the hospital-wide readmission measure is valid and can be used as a means to benchmark performance,” the authors wrote. “Moreover, there may be opportunities for worse-performing hospitals to improve their care and avert potentially preventable readmissions.”