Higher Hospital Readmission Rates Linked to Adverse Effects in Pneumonia

Randy Dotinga

June 29, 2022

Adding to the debate over the value of hospital readmission rates, a new study links the data to higher rates of adverse events in patients treated for pneumonia.

For each interquartile range increase in the readmission rate in a sample of 46,047 patients, the odds of adverse events grew by 13% (adjusted odds ratio, 1.13; 95% CI, 1.08-1.17), according to research that was published on May 31 in JAMA Network Open .

"The link between patient safety and overall hospital quality has not been explored in detail. This study supplements that knowledge and more specifically links readmission rate, which has been criticized as a measure of quality, with patient safety," said pulmonologist Mark Metersky, MD, of UConn Health, in an interview.

According to Metersky, it's clear that readmissions are extensive and expensive. "We also know that many are not preventable and that efforts to lower readmission rates have not been highly successful overall, although there have been some positive studies," he said. "We also know that CMS [Centers for Medicare & Medicaid Services] does use readmission rates to adjust payments to hospitals, and many are penalized financially. We do not know how effective financial penalties are in driving quality improvement. In fact, the evidence is not strong."

For the new study, he said, the researchers sought to understand more about readmission rates and pneumonia. "Both readmissions and patient safety are associated with the quality of hospital care, but it is unknown whether patients admitted to hospitals with higher risk-standardized readmission rates had a higher risk of in-hospital adverse events."

The researchers tracked patients with pneumonia across 2590 hospitals from 2010-2019 (mean age, 71; 52% women; 82% White persons; 12% Black persons; 46% with chronic obstructive pulmonary disease; 7% with in-hospital mortality).

"The median hospital-specific risk-standardized readmission rate was 17.0% (95% CI, 16.3%-17.7%), the occurrence rate of adverse events was 2.6% (95% CI, 2.54%-2.65%), and the number of adverse events per 1000 discharges was 157.3 (95% CI, 152.3-162.5)," the researchers reported.

In addition to the findings about adverse events in patients, the researchers linked each interquartile range increase to 5.0 more adverse events per 1000 discharges at the hospital level (95% CI, 2.8-7.2).

"Patients with pneumonia admitted to a hospital with a high readmission rate were more likely to suffer an adverse event while hospitalized, and hospitals with high readmission rates had higher rates of adverse events among their patients," Metersky said.

Although the 13% increase of adverse events at the patient level may not seem like much, "when considered on a hospital level (several hundred pneumonia admissions per year for larger hospitals) or at the national level (over 1.5 million admissions per year pre-COVID), a 13% increase in the number of adverse events becomes very large," he said. "And we know from prior work that these adverse events are important. They are associated with increased mortality and increased hospital length of stay."

The study notes that the data lack information about the severity of patient illnesses, but "the effect is probably not huge," Metersky noted.

The message of the study is that "readmission rates likely do reflect overall hospital quality, and factors that contribute to readmission rates might also contribute to patient safety/adverse event rates," he said.

Brad Wright, PhD, chair of the Department of Health Services Policy & Management at the University of South Carolina, said the study was "rigorously conducted" but is also limited. "They suggest that being admitted to a hospital with a higher readmission rate is associated with a higher probability of experiencing an adverse event during the hospitalization, but they are unable to speak to the causal mechanism."

Also, he said, "the authors only looked at pneumonia, so it is quite possible that the association they identify does not hold for other conditions."

Wright said clinicians and hospital administrators "should evaluate whether there are things that they are or are not doing during a patient's hospitalization that may be contributing to both adverse events and readmissions."

However, he added, "without further studies, I would generally be very reluctant to conclude from this that readmission rates should be used as a proxy for hospital quality or patient safety. There may be an association, but this study does not have the ability to tell us what is behind it."

The study is funded by the Agency for Healthcare Research. The study authors report various disclosures, including federal grant funding. Wright reported no relevant financial disclosures.

JAMA Network Open. 2022;5:e2214586. Full text

Randy Dotinga is a freelance journalist who specializes in health and medicine.

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